Term
| What does the central nervous system consist of? |
|
Definition
| the brain and spinal cord |
|
|
Term
| What does the peripheral nervous system consist of? |
|
Definition
the peripheral nerves:
efferent: nerves from the brain
afferent: nerves to the brain |
|
|
Term
| What are the two types of cell in the NS? |
|
Definition
| nerve cells and supporting cells |
|
|
Term
|
Definition
Neurones/neurons
100 billion
electrically active |
|
|
Term
| Describe supporting cells |
|
Definition
Neuroglia, glial cells and glia
1-3x as many as neurones |
|
|
Term
In the body, which parts of the following system are in the CNS?
sensory neurone
interneurone
motor neurone |
|
Definition
sensory neurone axon terminals
interneurone
motor neurone cell body |
|
|
Term
In the body, which parts of the following system are in the PNS?
sensory neurone
interneurone
motor neurone |
|
Definition
sensory neurone receptor and cell body
motor neurone axon terminal (which goes to the effector organ) |
|
|
Term
| What do excitatory neurones do and what is the most common neurotransmitter? |
|
Definition
they increase the activity of target cells
glutamate |
|
|
Term
| What do inhibitory neurones do and what is the most common neurotransmitter? |
|
Definition
they decrease the activity of target cells
gamma-amino butyric acid (GABA) |
|
|
Term
| What are myelinated glial cells and where are they found? |
|
Definition
Schwann cells in the PNS
Oligodendrocytes in the CNS |
|
|
Term
| What are the roles of astrocytes? (3) and where are they found? |
|
Definition
- provide nutrients to the nervous tissue
- principle role in the repair and scarring process in the brain
- supporting glia
- CNS only! |
|
|
Term
| What is the PNS astrocyte equivalent? |
|
Definition
|
|
Term
|
Definition
| immune cells of the CNS that clean CNS debris |
|
|
Term
|
Definition
| collection of neuronal cells in the CNS |
|
|
Term
|
Definition
| group of functionally related axons in the CNS |
|
|
Term
|
Definition
| a bundle of axons in the PNS |
|
|
Term
|
Definition
| a collection of neuronal cell bodies in the PNS |
|
|
Term
| What is the somatic nervous system also known as and what does it contain? |
|
Definition
voluntary nervous system
somatic motor neurons
sensory afferent fibres |
|
|
Term
| Describe efferent neurones |
|
Definition
Found in the CNS
Axons are heavily myelinated
Flows from CNS to effectors
Acetylcholine |
|
|
Term
| Describe afferent neurones |
|
Definition
Found in the PNS
Axons are either myelinated or unmyelinated
Sensory info to the CNS
Glutamate |
|
|
Term
|
Definition
| a structure containing a number of nerve cell bodies, typically linked by synapses, and often forming a swelling on a nerve fibre. |
|
|
Term
| What is the location of the ganglia in sympathetic NS? |
|
Definition
|
|
Term
| Describe the fibres in sympathetic NS |
|
Definition
Short myelinated pre-ganglionic fibres
Long post-ganglionic fibres that branch extensively |
|
|
Term
| What is the post-ganglionic neurotransmitter in sympathetic fibres? |
|
Definition
| acetylcholine (which bind to muscarinic receptors) |
|
|
Term
| What neurotransmitter and receptors are used in the PNS ganglion? |
|
Definition
|
|
Term
| What is the location of the ganglia in parasympathetic NS? |
|
Definition
| Ganglia close to/in target |
|
|
Term
| Describe the fibres in parasympathetic NS |
|
Definition
Long myelinated pre-ganglionic fibres
Short post-ganglionic that branches minimally |
|
|
Term
| What is the post-ganglionic neurotransmitter in sympathetic fibres? |
|
Definition
|
|
Term
| What does the enteric nervous system control? |
|
Definition
autonomously controls the activity of the GI tract
controls gut motility and secretion of enzymes and acids |
|
|
Term
| What does the enteric nervous system mainly consist of? |
|
Definition
|
|
Term
|
Definition
receives autonomic innervation from the vagus (parasympathetic) and sympathetic chain
vagus nerve |
|
|
Term
| What does the forebrain consist of? |
|
Definition
Cerebrum (cerebral hemispheres)
Thalamus
Hypothalamus |
|
|
Term
| What does the hindbrain consist of? |
|
Definition
|
|
Term
|
Definition
| smallest part of the brain that connects the hindbrain to the forebrain and contains several pathways important to hearing and vision. |
|
|
Term
| Define rostral and give another word for it |
|
Definition
| towards the head of the body (superior) |
|
|
Term
| Define caudal and give another word for it |
|
Definition
| towards the tail of the body (inferior) |
|
|
Term
| Define ventral and give another word for it |
|
Definition
| towards the front of the body (anterior) |
|
|
Term
| Define posterior and give another word for it |
|
Definition
| towards the back of the body (posterior) |
|
|
Term
| Define gyri and sulci and what their roles are |
|
Definition
Gyri = ridges in the brain
Sulci = grooves in the brain
Increase the amount of cerebral cortex that can fit in the skull |
|
|
Term
| What are the axis of the brain caused by? |
|
Definition
|
|
Term
| What joins the two hemispheres and from which view of the brain is this visible? |
|
Definition
Corpus callosum: a broad band of nerves joining the two brain hemispheres (contains 200 million axons)
Midsagittal |
|
|
Term
| What is the reticular formation? |
|
Definition
| network of nerve pathways in the brainstem (hindbrain) connecting the medulla and midbrain. Responsible for alterness and CV function. |
|
|
Term
|
Definition
found in midline areas of medulla and midbrain
contain a large proportion of 5-HT containing cells which project to either the spinal cord or forebrain |
|
|
Term
| What is the area prostrema? |
|
Definition
medulla/pons structure that contain chemoreceptor trigger zone (CTZ)
controls vomitting |
|
|
Term
| What is the locus coeruleus |
|
Definition
structure in pons
contrains noradrenaline postive cells |
|
|
Term
| What does the reticular formation receive information from? (5) |
|
Definition
- spinal cord ascending tracts
- descending axons from cranial nerves, vestibular and cochlear reflexes
- cerebellum
- thalamus
- frontal, sensory and motor areas of the cortex |
|
|
Term
| What are the functions of dopamine pathways? (5) |
|
Definition
- reward (motivation)
- pleasure, euphoria
- motor function
- compulsion
- preservation |
|
|
Term
| What are the functions of serotonin pathways? (4) |
|
Definition
- mood
- memory processing
- sleep
- cognition |
|
|
Term
| What is the substantia nigra? |
|
Definition
in the midbrain
made up of dopamine containing cells
responsible for the motor system |
|
|
Term
| Why does the substantia nigra appear darker? |
|
Definition
| due to presence of neuromelanin |
|
|
Term
| What disease affects the cells of the substantia nigra? |
|
Definition
|
|
Term
| What is the role of the superior colliculus? |
|
Definition
in the midbrain
receives visual inputs
brings eyes to focus of attention in conjunction with motor system |
|
|
Term
| What is the role of periaqueductal grey matter? |
|
Definition
control of somatic pain sensations (emotive pain pathways and fear)
mid brain |
|
|
Term
|
Definition
motor control structure in the midbrain
more active babies |
|
|
Term
| What is the role of the thalamus? |
|
Definition
| receives sensory information and sends signals to muscles. Relay centre in the brain. |
|
|
Term
| What is the role of the hypothalamus? |
|
Definition
| involved in homeostasis and endocrine functions |
|
|
Term
| What does the hypothalamus respond to? |
|
Definition
heart rate
hunger
water balance
blood loss
body temperature
level of sex hormones in the blood
other limbic system structures |
|
|
Term
| What is the role of the pituitary gland? |
|
Definition
| important for hormone release |
|
|
Term
|
Definition
| a collection of structures involved in mood and emotion. |
|
|
Term
| What is the cerebral cortex? |
|
Definition
| outer layer of the cerebral hemisphere. |
|
|
Term
| What is below the cerebral cortex? |
|
Definition
| white matter consisting of large bundles of axons which are projections to and from the thalamus and from the cortex to the cerebellum, brain stem and spinal cord. |
|
|
Term
| What is the role of the basal ganglia |
|
Definition
| participate in the control of motor activity |
|
|
Term
| What diseases cause degeneration of the basal ganglia |
|
Definition
| Parkinsons and Huntingtons |
|
|
Term
| What are the major regions of the brain |
|
Definition
Frontal lobe
Parietal lobe
Temporal lobe
Occipitial lobe
Cerebellum
Brainstem |
|
|
Term
| What is the role of the frontal lobe |
|
Definition
conscious thought
planning
control of movement |
|
|
Term
| What is the role of the parietal lobe |
|
Definition
|
|
Term
| What is the role of the temporal lobe |
|
Definition
hearing
learning
memory
emotion |
|
|
Term
| What is the role of the occipital lobe |
|
Definition
|
|
Term
| What is the cerebral cortex split into |
|
Definition
somatosensory cortex (left, sensory homunculus)
motor cortex (right, motor homunculus) |
|
|
Term
|
Definition
| 3 layers of protective tissue that enclose the brain and spinal cord |
|
|
Term
| What are the 3 meninges layers? |
|
Definition
Dura mater
Arachnoid mater
Pia mater |
|
|
Term
| Describe the outermost meninges layer |
|
Definition
Dura Mater
thickest membrane which protects the CNS
not very flexible |
|
|
Term
| Describe the middle meninges layer |
|
Definition
Arachnoid mater
Does not enter sulci
Below is CSF and has spider-like projections |
|
|
Term
| Describe the innermost layer |
|
Definition
lies on the surface of the brain and spinal cord
enters sulci |
|
|
Term
| What are the cerebral ventricles? |
|
Definition
| series of interconnected fluid filled spaces that lie in the core of the forebrain and brainstem, Filled with cerebrospinal fluid (CSF) |
|
|
Term
What is CSF?
where is it produced
where does it go |
|
Definition
produced at site of the choroid plexus
flows through the ventricle system
eventually absorbed into venous circulation
flows into subarachnoid space and cleans brain |
|
|
Term
|
Definition
| a segmented column with 30 pairs of spinal nerves attached to it |
|
|
Term
| What are spinal nerves made of |
|
Definition
| afferent and efferent axons from dorsal (sensory) and ventral (motor roots) |
|
|
Term
| Where do dorsal roots originate from? |
|
Definition
| a cluster of cells bodies in dorsal root ganglion |
|
|
Term
| Where do dorsal roots sent processes to? |
|
Definition
| the sensory receptors and grey matter of spinal cord |
|
|
Term
| How many sensory nerve branches are there? |
|
Definition
|
|
Term
| Describe the sensory nerves |
|
Definition
- ascends to brainstem
- terminates locally in the spinal cord
- ascend a few segments to coordinate upper and lower muscle systems |
|
|
Term
| Compare rat brains to human brains |
|
Definition
- rat brain lacks folds because they have less neurones
- they have 'old factory' bulbs due to their very acute sense of smell |
|
|
Term
| How are neurones classified? (5) |
|
Definition
- number of neurites
- dendrites
- connections
- axon length
- neurotransmitter |
|
|
Term
| Give examples of neurones classified by number or neurites |
|
Definition
unipolar
bipolar
multipolar |
|
|
Term
| Give examples of neurones classified by dendrites |
|
Definition
| shape of dendrite tree: pyramidal or stellate |
|
|
Term
| Give examples of neurones classified by connections |
|
Definition
sensory
motor
interneurones |
|
|
Term
| Give examples of neurones classified by axon length |
|
Definition
projection neurone
local circuit neurone |
|
|
Term
| Give examples of neurones classified by neurotransmitter |
|
Definition
acetylcholine
GABA
glutamate |
|
|
Term
| What do glial cells do and do not do in the CNS |
|
Definition
| do not form chemical synapses with neurons although do participate in electrical signalling. |
|
|
Term
| What are the functions of glial cells |
|
Definition
-support: help define synpatic contact and maintain signalling abilities of neurones
-mop up excess ions
-modulate rate of nerve signal propagation
-uptake NT after chemical neurotransmission
-aid recovery from neural injury
-help in neuronal development |
|
|
Term
| How can the potential difference of a membrane be measured? |
|
Definition
| stick electrodes inside neurones and measure the potential difference between inside and outside of cell |
|
|
Term
|
Definition
actively move ions against conc gradient
create ion conc gradients |
|
|
Term
|
Definition
allow ions to diffuse down conc gradient
cause selective permeability to ions |
|
|
Term
| What causes channels to open? |
|
Definition
1.chemicals (ligands/neurotransmitters)
2.voltage changes (voltage gated)
3.mechanically (eg stretch activated) |
|
|
Term
| Describe extracellular ion concentrations at the resting membrane potential |
|
Definition
|
|
Term
| Describe intracellular ion concentrations at the resting membrane potential |
|
Definition
|
|
Term
| Describe relative permeability of ion concentrations at the resting membrane potential |
|
Definition
|
|
Term
| Which factors contribute to the resting membrane potential? |
|
Definition
1. charged intracellular proteins
2. the Na+/K+ pump
3. potassium ions
4. sodium ions |
|
|
Term
| What else contributes to the negative intracellular space |
|
Definition
| large negatively charged intracellular proteins that cannot cross the membrane |
|
|
Term
| What does the Na+/K+ pump do? |
|
Definition
-moves 3Na+ ions out for every 2K+ in (SO GET OUT, OKAY YOU CAN COME IN)
- thus inside becomes more negative |
|
|
Term
| Describe the forces acting on K+ and what they become together |
|
Definition
K+ is forced out due to concentration gradient (membrane is freely permeable to K+)
K+ is forced in due to electrical gradient (because inside is -ve)
These become in equilibrium at rest |
|
|
Term
| What is the resting membrane potential |
|
Definition
|
|
Term
| Describe the forces acting on Na+ and what they become together |
|
Definition
Na+ is forced in due to concentration gradient (membrane is freely permeable to K+)
Na+ is forced in due to electrical gradient (because inside is -ve)
The membrane is only slightly permable to Na+ so the cell only becomes slightly more positive |
|
|
Term
| What does the Nernst equation calculate |
|
Definition
| the equilibrium potential of any ion (Eion) |
|
|
Term
| Define Equilibrium Potential (Eion) |
|
Definition
| the electrical potential difference that exactly balances an ionic concentration gradient |
|
|
Term
| Define ionic driving force |
|
Definition
| the difference between the real membrane potential (Vm) and rhw equilibrium potential (Eion) |
|
|
Term
| What else must be taken into consideration with the Nernst equation to calculate the RMP? |
|
Definition
-Na+ flow into the cell at rest too
-Use the Goldrian-Hodgkin-Katz (GHK) equation to calculate Vm |
|
|
Term
| What are the factors that determine the resting membrane potential? |
|
Definition
1. at rest, the membrane is relatively permeable to membrane ions
2. large negatively charged intracellular proteins (make inside -ve)
3. little leak to Na+ ions (into cell)
4. Na/K pump causes net loss of positive charge inside cell |
|
|
Term
|
Definition
| when a neurone sends information down an axon, away from the cell body. |
|
|
Term
|
Definition
| an explosion of electrical activity that is created by a depolarising current, usually from a synaptic input from another neurone |
|
|
Term
| What are graded potentials? |
|
Definition
| changes in membrane potential that can be stimulated by injecting a current |
|
|
Term
| How can graded potentials vary? |
|
Definition
they can be hyper-polarising or depolarising
varied magnitude |
|
|
Term
| How does a wave of depolarisation occur |
|
Definition
- A stimulus results in a small patch of membrane becoming depolarised
- as positive ions flow towards -ve area (and -ve to +ve) local currents are created that depolarise adjacent membranes |
|
|
Term
| How does is the membrane potential altered |
|
Definition
1. insertion of the electrode into the cell reveals a negative potential, the resting potential (-65mV)
2. inject a current through the current passing micro-electrode |
|
|
Term
| What do hyper-polarising current pulse produce? |
|
Definition
| negative charge produces only passive changes in the membrane potential |
|
|
Term
| What do depolarising current pulse produce? |
|
Definition
| cause passive changes unless threshold is reached |
|
|
Term
|
Definition
| when threshold is reached |
|
|
Term
|
Definition
1. rising phase (depolarisation)
2. overshoot phase
3. falling phase (re-polarisation)
4. undershoot phase (after hyper-polarisation) |
|
|
Term
| Describe the changes in permeability of Na+ |
|
Definition
| roughly follows the pattern of an AP |
|
|
Term
| Describe the changes in permeability of K+ |
|
Definition
| Increases during re-polarisation and then falls again |
|
|
Term
| Describe the events of resting state of an AP |
|
Definition
all voltage gates Na and K channels closed
(these are different to the ones open at rest) |
|
|
Term
| Describe the events of depolarisation of an AP |
|
Definition
| fast activation of gates which cause sodium channels to open |
|
|
Term
| Describe the events of repolarisation of an AP |
|
Definition
| inactivation of gates: Na+ channels close and K+ open |
|
|
Term
| Describe the events of undershoot of an AP |
|
Definition
K+ channels remain open
Na+ channels closed |
|
|
Term
| Describe the events of resting state of an AP |
|
Definition
| all voltage gates Na and K channels closed |
|
|
Term
| What does a larger stimuli cause |
|
Definition
| greater number of action potentials (constant amplitude) |
|
|
Term
| List the different preparations used in electrophysiology |
|
Definition
Single cells
Brain or spinal cord slices
Larger in vitro preparations (the brainstem spinal cord)
Intact nerve
Invertebrate preparations (eg snail brain) |
|
|
Term
| Which preparations are most stable and what does this mean? |
|
Definition
SIngle cells, brain or spinal cord slices, larger in vitro preparations
no blood pressure or breathing pressure movement |
|
|
Term
| Describe single cell preparations and |
|
Definition
- isolated neurone preparations (cultures etc)
- no synaptic connections (isolated) |
|
|
Term
| What are single cell preparations used for? |
|
Definition
| to find resting membrane potential/action potentials/how many APs/size |
|
|
Term
| Describe brain or spinal cord slices |
|
Definition
| neurones in vitro with local synaptic connections intact |
|
|
Term
| What are brain or spinal cord slices preparations used for? |
|
Definition
how cells communicate with each other (excitatory/inhibitory)
used to record neuronal activity in an in vitro situation |
|
|
Term
| Describe larger in vitro preparations |
|
Definition
| - longer connections are maintained here |
|
|
Term
| What are large in vitro preparations used for and how? |
|
Definition
used to see whether neurones are synapsing
stimulate the brain and record a synapse in the spinal cord |
|
|
Term
| Which preparation would be used to study local synaptic circuits? |
|
Definition
|
|
Term
| How is a brain slice prepared? |
|
Definition
- remove brain quickly from an anaesitised/sacrificed animal
- section brain tissue of interest in an artificial CSF (continuously oxygenated and 3mm thickness)
- use a vibroslice to obtain slices |
|
|
Term
| What do we use electrophysiology to measure? |
|
Definition
1. membrane potential
2. action potentials
3. synaptic potentials
4. current flow through ion channels
5. action potential propagation
6. action potential firing rates |
|
|
Term
| Describe current clamp recording: (intracellular) |
|
Definition
| Glass electrode impales neuron and measures voltage inside cell compared to outside (ground). A current can also be injected into the cell through the electrode to de/hyperpolarise the membrane |
|
|
Term
| What is current clamp recording useful for measuring? |
|
Definition
- resting membrane potential
- action potentials
- firing rate and synaptic potentials
most commonly used to record 'blind' from neurones in brain slices |
|
|
Term
How can the morphology of the neurone be studied?
(form, shape, or structure) |
|
Definition
1. fill the electrode with a dye
2. dye diffuses throughout the cytoplasm of neurone
3. dye can be visualised using light microscopy
4. allows for correlation of electrophysiological and neuroanatomical properties |
|
|
Term
| What does extracellular recording, record? |
|
Definition
records voltage fro outside the cell, small signals, inverted signals
useful for recording AP firing rates without impaling the neurone
measure field potentials (synaptic potentials) from large population of neurons |
|
|
Term
| What does a multi-barrelled electrode allow in extracellular recording? |
|
Definition
| simultaneous recording and application of a number of different drugs (called microiontophoresis) |
|
|
Term
| What is a voltage clamp used for? |
|
Definition
| controlling the membrane potential (voltage) across the cell membrane to measure the current flowing through ion channels |
|
|
Term
| What was the Hodgkin and Huxley experiment and what did it discover? |
|
Definition
- They studied the giant squid axon and measured the conductance through voltage gated ion channels whilst controlling (clamping) the voltage across the membrane.
- first complete description of the ionic mechanisms underlying the AP. |
|
|
Term
| In the H&H experiment, what did the recording electrode measure? |
|
Definition
| the membrane potential (Vm) and it was connected to the voltage clamp amplifier. |
|
|
Term
| In the H&H experiment, what did the voltage clamp amp do? |
|
Definition
| compared membrane potential to the desired potential (set by the experimenter) |
|
|
Term
| What happens when the Vm is different to the desired potential? |
|
Definition
| the voltage clamp amp injects current into the axon through the second (current passing) electrode. The current passed through the axon and thus across the axon is recorded. |
|
|
Term
| What do we figure out which current is involved? |
|
Definition
| block different ion channels |
|
|
Term
| What is added to block K channels and what does this leave? |
|
Definition
tetraethyl ammonium
leaves inward current |
|
|
Term
| What is added to block Na channels and what does this leave? |
|
Definition
tetradotoxin
leaves outward current |
|
|
Term
| What does current clamp recordings measure |
|
Definition
changes in membrane potential (eg AP)
sometimes called intracellular recordings |
|
|
Term
| What does voltage clamp recording measure |
|
Definition
changes in current (conductance) eg ionic currents underlying AP
clamp the membrane potential at set values and measure currents |
|
|
Term
| Describe patch clamp recording |
|
Definition
1. a glass recording electrode is placed against the membrane of a neuron and gentle suction is applied
2. a very high resistance 'seal' is formed between the glass and the membrane (gigachm seal)
3. various recording configurations can be obtained to record electrical activity from the cell |
|
|
Term
| Describe single channel recording |
|
Definition
- remove a part of a membrane and look at it in isolation
- single Na+ channels open in response to depolarisation
- measures microscopic currents |
|
|
Term
| What are xenopus oocytes used for? |
|
Definition
- mrna sequence of ion channels can be injected into oocytes and will express the functional channels
- two electrode voltage clamp recordings can be made from oocytes due to their large size
- properties of the ion channel can be studied in isolation |
|
|
Term
|
Definition
Families with a gene mutation have a history of epilepsy.
The gene mutation is found – this region encodes a potassium channel
The mutation is expressed in oocytes and we can look at how the potassium currents are affected |
|
|
Term
| How is brain tissue prepared for light microscopy? |
|
Definition
1. sliced very thin so individual cells can be resolved under the microscope
2. brain tissue is very soft and must be fixed using formaldehyde
3. brain tissue is then sectioned using a microtome (10-200 um thick)
4. stains selectively colour some brain tissue cells |
|
|
Term
| What is the role of formaldehyde? |
|
Definition
fixes proteins
prevents autolysis
decomposition |
|
|
Term
| How dos a vibratome work? |
|
Definition
|
|
Term
| How does a cryostat work? |
|
Definition
|
|
Term
| How does ultramicrotome work? |
|
Definition
| diamond knife (nanometer sections) |
|
|
Term
|
Definition
DAPI
Nissl
Golgi
Nauta silver stain |
|
|
Term
| What is DAPI used to detect? |
|
Definition
| DNA in living and fixed neurones |
|
|
Term
|
Definition
|
|
Term
| What is Nissl stain used to detect? how? |
|
Definition
neurones and glia in the brain
stains the nuclei and clumps of material (Nissl bodies - rough ER) surrounding nuclei in neurones |
|
|
Term
| What does Nissl stain label? |
|
Definition
selectively labels neurones and glia
only labels nucleus region of the neurone (not neurites or axon terminals) |
|
|
Term
| What does Nissl stain indicate? |
|
Definition
|
|
Term
| What does Golgi stain, stain? |
|
Definition
both the cell body and neurites of the neurone
only stains a proportion of neurones in the tissue slice |
|
|
Term
| What did Golgi believe and who corrected him? |
|
Definition
neurones were fused together
Cajal |
|
|
Term
| What was Cajal's neurone doctrine? |
|
Definition
used Golgi stain
neurones are like other body cells and were the elementary unit of the brain |
|
|
Term
| What resolutions do electron and light microscopes have respectively? |
|
Definition
0.1nm
0.1um
(electron has higher resolution) |
|
|
Term
| What was an electron microscope used to reveal? |
|
Definition
used to tell if neurones are connected or not as the synapse is 0.02um
revealed the existence of synapses and neurone ultrastructure in mitochondria |
|
|
Term
| How does a transmission electron microscope work? |
|
Definition
1. a stream of electrons is formed and accelerated towards the specimen using a positive electrical potential in a vacuum
2. electron stream is confined and focused using metal apertures and magnetic lenses into a thin focused, monochromatic beam
3. beam is focused onto the sample using a magnetic lens
4. imagine is formed by electron-tissue interaction detections |
|
|
Term
| What is immunohistochemistry? |
|
Definition
| Manufacturing antibodies appropriate for a specific protein that wants to be visualised inside a neurone. Allows a discrete labelling of cells that contain the candidate protein and is useful for localising cells using a particular neurotransmitter. |
|
|
Term
| How can multiple different proteins be tagged at the same time? |
|
Definition
| by using fluorescent tags alongside a microscope fitted with a fluorescent source (eg UV lamp) |
|
|
Term
| How do fluorophores work? |
|
Definition
1. fluorophore absorbs a very specific wavelength of light
2. this excites electrons up to a higher level, they drop down and longer wavelength of light is emitted (therefore some energy has been lost). |
|
|
Term
| what wavelength of light does red and green emit? |
|
Definition
|
|
Term
| Define axoplasmic transport |
|
Definition
| neurones use microtubules to transport substances from the cell body to the axon terminal |
|
|
Term
| What is considered fast and slow axoplasmic transport? |
|
Definition
Fast = 1000mm per day
Slow = 1-10mm per day |
|
|
Term
| Define anterograde transport |
|
Definition
| movement of substances from the soma to axon terminals |
|
|
Term
| Define retrograde transport |
|
Definition
| movement of substances from the axon terminals to the soma |
|
|
Term
| How do scientists trace the path of axons in the brain? |
|
Definition
using axoplasmic transport
1. enzymes are injected into living brain tissue
2. enzyme is taken up by axon terminals and retrogradely transported to the cell body
3. staining is used to visualise enzyme location in brain tissue |
|
|
Term
| Which enzyme could be used |
|
Definition
|
|
Term
| What is trans-neuronal tracing? |
|
Definition
more than one synapse
2 different coloured tracers can be injected in 2 different areas (eg thalamus and ganglion) |
|
|
Term
| Define electrical transmission |
|
Definition
| direct flow of ions from one neurone to another, hence direct influence of electrical current from one to another (eg gap junctions) |
|
|
Term
|
Definition
are a specialized intercellular connection between a multitude of animal cell-types. They directly connect the cytoplasm of two cells, which allows various molecules, ions and electrical impulses to directly pass through a regulated gate between cells.
(half of the gap junction is in either neurone membrane) |
|
|
Term
|
Definition
6 connexin molecules
two connexons make a gap junction |
|
|
Term
| What are gap junctions modulated by? |
|
Definition
ph
neurotransmitters
intracellular calcium |
|
|
Term
| Define chemical neurotransmission |
|
Definition
| neurotransmitter substance released from pre-synaptic cleft, diffuses across synaptic cleft, produces effect on postsynaptic neuron (eg central synapse) |
|
|
Term
| What is the distance between pre and post synaptic cell membranes in electrical synapses? |
|
Definition
| 3.5nm (to allow for Henry channels) |
|
|
Term
| What is the distance between pre and post synaptic cell membranes in chemical synapses? |
|
Definition
| 30-50nm (allowed by diffusion) |
|
|
Term
| Do electrical synapses have cytoplasmic continuity between pre and post synaptic cell membranes? |
|
Definition
| Yes because Henry channels form |
|
|
Term
| Do chemical synapses have cytoplasmic continuity between pre and post synaptic cell membranes? |
|
Definition
|
|
Term
| What are the ultrastructural components of electrical synapses |
|
Definition
|
|
Term
| What are the ultrastructural components of chemical synapses |
|
Definition
Pre-synpatic active zones and vesicles
post synaptic receptors |
|
|
Term
| What is the agent of transmission in electrical synapses? |
|
Definition
|
|
Term
| What is the agent of transmission in chemical synapses? |
|
Definition
|
|
Term
| Do electrical synapses have a synaptic delay? |
|
Definition
|
|
Term
| Do chemical synapses have a synaptic delay? |
|
Definition
|
|
Term
| Do electrical synapses have a synaptic delay? |
|
Definition
| at least 0.3ms, usually 5ms |
|
|
Term
| What is the direction of transmission in electrical synapses? |
|
Definition
|
|
Term
| What is the direction of transmission in electrical synapses? |
|
Definition
|
|
Term
| Do electrical synapses show flexibility |
|
Definition
|
|
Term
| Do chemical synapses show flexibility |
|
Definition
| Great flexibility due to transmitters and post synaptic response |
|
|
Term
| What are the 5 stages of neurotransmission |
|
Definition
1. synthesis
2. storage
3. release
4. post-synaptic effects
5. inactivation |
|
|
Term
| Where are amino acids and amino neurotransmitters synthesised |
|
Definition
| axon nerve terminal using synthesising enzymes that are transported from the cell body |
|
|
Term
| Where and how are peptides synthesised |
|
Definition
| in the cell body using protein manufacturing components and transported to the nerve terminal |
|
|
Term
| How and where are neurotransmitters stored? |
|
Definition
NT are taken up into vesicles by transporters.
Vesicles cluster at regions called active zones. |
|
|
Term
| What causes synaptic release and what happens to the vesicles? |
|
Definition
synaptic release occurs as a result of a rise in intracellular calcium.
vesicles discharge NT into the synaptic cleft and are recycled |
|
|
Term
|
Definition
1. broken down in synaptic cleft
2. undergoes re-uptake into terminal
3. diffuses away from synaptic region |
|
|
Term
|
Definition
| NT may bind to an auto-receptor on the pre-synaptic membrane which modulates transmission. |
|
|
Term
| Name the 4 main neurotransmitters |
|
Definition
Acetylcholine
Amines
Peptides
Amino acids |
|
|
Term
| Where is acetylcholine found? |
|
Definition
1. neuromuscular junction (released by motor neurones and enables contraction)
2. CNS: muscarinic and nicotinic receptors |
|
|
Term
| Give examples of amine NT |
|
Definition
DA
NA
NE
Histamine
5-HT
Adrenaline |
|
|
Term
| What are peptide NT critical for? |
|
Definition
| central and peripheral NS |
|
|
Term
| Give examples of amino acid NTs |
|
Definition
GABA and glycine (inhibitory NT)
Glutamate (major excitatory aa in brain, critical for excitatory neurotransmission). |
|
|
Term
| What define a chemical messenger as a neurotransmitter |
|
Definition
1. must be synthesised in the neurone
2. must be present in the presynaptic terminal and be released in sufficient amounts to exert its supposed effects on postsynaptic neurone
3. when applied exogenously in reasonable concentrations, it must mimic exactly the actions of the endogenously released transmitter
4. there must be a specific mechanism for removing it from site of action |
|
|
Term
| What are the types of storage synaptic vesicles? |
|
Definition
`Small clear vesicles (40-60nm): small molecule neurotransmitters
Large dense core vesicles (90-250nm): neuropeptide |
|
|
Term
| Define co-existence/co-transmission |
|
Definition
| when a single neurone synthesises and releases more than one transmitter substance |
|
|
Term
| Describe how calcium influx arrises and how this causes NT release |
|
Definition
1. AP arrives in the pre-synaptic terminal causing depolarisation
2. this opens voltage gated calcium channels to open
3. calcium rushes into the terminal at active zone
4. calcium ions trigger NT release |
|
|
Term
| Describe synaptic vesicle cycling |
|
Definition
1. free vesicles are target-ed to the active zone
2. vesicles dock with the active zone
3. the docked vesicle is primed for exocytosis |
|
|
Term
| What causes vesicle release and how |
|
Definition
Due to increased intracellular calcium, vesicles undergo fusion and release their contents
the fused vesicle membrane is taken up into the cell by endocytosis |
|
|
Term
|
Definition
| proteins found on vesicles and pre-synaptic terminal membrane |
|
|
Term
| What is synaptobrevin and what is its role |
|
Definition
vesicle bound protein with SNAP-25 on plasma membrane
vesicle docking/priming |
|
|
Term
| What is synaptotagmin and what is its role |
|
Definition
Ca2+ sensor
Enables vesicle to fuse with presynaptic membrane to release neurotransmitter |
|
|
Term
| What are the two types of post-synaptic receptors? |
|
Definition
metabotropic receptors
ionotropic receptors |
|
|
Term
| Describe metabotropic receptors |
|
Definition
coupled to intracellular proteins that transduce the signal to the cell interior
slow response |
|
|
Term
| Describe ionotropic receptors |
|
Definition
form ion channels that depolarise or hyperpolarise the post-synaptic cell
fast response |
|
|
Term
| How do pre and post synaptic APs differ? |
|
Definition
pre is a standard AP
post are either excitatory (EPSP) or inhibitory (IPSP)
post are a sudden increase/decrease and then steady decline |
|
|
Term
| Describe electrical synapses |
|
Definition
- facilitates communication between neural cells
- ions move directly between neurones |
|
|
Term
| Describe chemical synapses |
|
Definition
| - chemical NT diffuse across the synaptic cleft from one neurone to the other |
|
|
Term
| Are there more electrical or chemical synapses? |
|
Definition
|
|
Term
| How many known neurotransmitters are there? |
|
Definition
|
|
Term
| Give examples of small molecule neurotransmitters: |
|
Definition
amino acids
Ach
ATP
biogenic amines
5-HT
Endocannobinoids (lipids)
NO |
|
|
Term
| Where do small molecule NT come from? |
|
Definition
| they are synthesised by enzymes in the presynaptic neurone |
|
|
Term
| What are large molecule NT and where do they come from? |
|
Definition
| peptides are encoded within the genome |
|
|
Term
| What is the main excitatory neurotransmitter in the CNS? |
|
Definition
|
|
Term
| Where is glutamate formed from? |
|
Definition
| from glutamine by the enzyme glutaminase |
|
|
Term
| Which transporters are used to put glutamate into vesicles? |
|
Definition
|
|
Term
| What are the effects of glutamate? |
|
Definition
binds to post-synaptic receptors and allow influx of sodium ions (some allow Ca2+)
generates EPSP |
|
|
Term
| What is the fate of glutamate? |
|
Definition
| will diffuse away and will be taken up by transporters (EAAT) |
|
|
Term
| Where can glutamate be taken up into? |
|
Definition
| back into the neurone or by glial cells |
|
|
Term
| How many synapses release glutamate? |
|
Definition
|
|
Term
| What does too much glutamate cause? |
|
Definition
excitotoxicity
eventual neuronal cell death |
|
|
Term
| What conditions cause too much glutamate |
|
Definition
ischaemia
epilepsy (seizures)
hypoglycaemia
trauma |
|
|
Term
| What is the main inhibitory neurotransmitter in the CNS? |
|
Definition
|
|
Term
| Where is GABA formed from? |
|
Definition
| produced from glutamate and glutamic acid decarboxylase and pyridoxal phosphate |
|
|
Term
| Which transporters are used to put GABA into vesicles? |
|
Definition
|
|
Term
| What are the effects of GABA? |
|
Definition
bind to receptors on postsynaptic membrane and allow Cl- through
Cl- enter the cell and more negative and therefore move away from threshold potential
generates IPSP by inhibiting AP firing due to influx of Cl- |
|
|
Term
| What is the fate of GABA? |
|
Definition
Taken up by glial cells or back into the neurone
by GABA transporters |
|
|
Term
| How many synapses release GABA? |
|
Definition
|
|
Term
| What does potenation of GABA signalling cause? |
|
Definition
| can reduce anxiety and be intoxicating |
|
|
Term
| What can GABA signalling potenation be caused by? |
|
Definition
- benzodiazepines (antidepressants, hyponotics)
- babiturates (epilepsy)
- alcohol (intoxication and ataxia) |
|
|
Term
| Name some catecholamines and state how else they are related |
|
Definition
dopamine, noraepinephrene and epinephrine
all synthesised along the same pathway |
|
|
Term
| Which drugs affect the dopamine/5-HT pathway? |
|
Definition
antidepressants (eg prozac) - block 5-HT reuptake
cocaine blocks reuptake
ecstacy affects vesicular transport
antipsychotic (eg haloperidol) inhibits dopamine |
|
|
Term
| What does low frequency stimulation cause release of? |
|
Definition
| small molecule neurotransmitter |
|
|
Term
| What does high frequency stimulation cause release of? |
|
Definition
| release of both small and large dense core vesicles |
|
|
Term
| What effect do peptides have and how do they achieve this? |
|
Definition
modulatory (pain and emotion/stress/appetite)
they bind to other cells to cause an internal change |
|
|
Term
| Which peptides are involved in modulating pain? |
|
Definition
|
|
Term
|
Definition
first peptide NT identified
release associated with pain signalling |
|
|
Term
|
Definition
inhibits substance P release
analgesic
inhibitory |
|
|
Term
| How is a NT signal terminated? give examples |
|
Definition
1. inactivation of NT (eg ACH by cholinesterase)
2. reuptake of NT (ege glutamate, gaba, 5-ht..)
3. diffusion away from synapse (eg peptide) diffusion is slow and therefore long lasting action |
|
|
Term
| What are ionotropic receptors? |
|
Definition
- made up of subunits
- one subunit will bind to the neurotransmitter
- binding causes the pore to open and ions travel through |
|
|
Term
| What are the individual subunits like in an ionotropic receptor? |
|
Definition
either:
- four transmembrane helices
- three transmembrane helices and a pore loop |
|
|
Term
| Which transmembrane domain always faces inwards? |
|
Definition
M2
responsible for regulating passing ions |
|
|
Term
| What effect does having a larger channel have? |
|
Definition
| calcium would be allowed through |
|
|
Term
| Describe the nACH receptior |
|
Definition
bind Ach
permeable to Na+, K+ and sometimes Ca2+
5 subunits |
|
|
Term
| Describe the NMDA receptor |
|
Definition
binds glutamate and glycine (co-agonist)
permeable to Na+, K+ and Ca2+
regulate synaptic plasticity and enhancing synaptic activity |
|
|
Term
| How can an NMDA receptor be blocked? |
|
Definition
| if an Mg2+ enters and binds |
|
|
Term
| Describe the NMDA receptor at resting potential |
|
Definition
1. glutamate is released from the presynaptic membrane
2. glutamate binds to AMPA receptors and Na+ is allowed in and K+ out (depolarised)
3. glutamate bind to NMPA receptors and channel opens
4. Mg2+ blocks channel |
|
|
Term
| What effect does depolarisation have? |
|
Definition
| depolarisation reduces the driving force of Mg2+ so Mg2+ diffuses out of the channel |
|
|
Term
| What effect does Mg diffusing out of the channel have? |
|
Definition
| no driving force for Na+ to come in so the cell becomes repolarised and Mg2+ slowly comes back |
|
|
Term
| What occurs if there is a signal before Mg2+ re-entering |
|
Definition
glutamate can bind and Na and Ca can come in
this will generate a second messenger signal |
|
|
Term
| Describe the GABAa receptor |
|
Definition
mediates inhibitory neurotransmission
5 subunits
binds GABA
allow Cl- in or out |
|
|
Term
| Which other molecules can bind on a GABAa receptor? |
|
Definition
-benzodiazepine
-barbiturates
-steroids
-picrotoxin |
|
|
Term
| Describe metabotropic receptors (eg GPCRs) |
|
Definition
monomeric proteins
7 transmembrane domains |
|
|
Term
| Describe metabotropic receptors domains |
|
Definition
extracellular = NT binding (domains 2,3,6 and 7)
intracellular = binding G-proteins |
|
|
Term
| Where do G-proteins bind? |
|
Definition
| loop between domains 5 and 6 and to portions of the C terminus |
|
|
Term
| Describe the norapinephrine mechanism |
|
Definition
1. beta-adrenergic receptor
2. Gs
3. adenylyl cyclase
4. cAMP
5. protein kinase A
6. increase protein phosphorylation |
|
|
Term
| Describe the glutamate mechanism |
|
Definition
1. mGLuR 1
2. Gq
3. phospholipase C
4a. diacycglycerol
4b IP3
5a PKC
5b Ca2+ release
6 increase protein phosphorylation and activate calcium binding proteins |
|
|
Term
| Describe the other glutamate mechanism |
|
Definition
1. mGLuR 2
2. Gi
3. adenylyl cyclase
4. cAMP
5. PKA
6. decrease protein phosphorylation |
|
|
Term
| Define somatosensory system |
|
Definition
| responds to the external environment |
|
|
Term
| Define viscerosensory system |
|
Definition
| response to the internal environment |
|
|
Term
| What is the skin and deeper structures (eg muscle/viscera) innervated by? |
|
Definition
| a rich vast network of peripheral nerves |
|
|
Term
| What do primary afferents do? |
|
Definition
| axons bringing information from the somatic receptors |
|
|
Term
| What do motor efferents do? |
|
Definition
| axons taking information from CNS to peripheral structures |
|
|
Term
|
Definition
| feed into the spinal cord via a spinal nerve and the dorsal root |
|
|
Term
|
Definition
| leave the spinal cord via a ventral root and the spinal nerve |
|
|
Term
| What does the somatosensory system detect |
|
Definition
|
|
Term
| How are somatosensory receptors classified? |
|
Definition
tactile (innocuous) sensations
thermal sensations
nociceptive (painful sensations) |
|
|
Term
| What are tactile sensations mediated by |
|
Definition
| mechanoreceptors (Merkel, Ruffini, Meissner and Pacinian) |
|
|
Term
| What are thermal sensations mediated by |
|
Definition
| thermoreceptors localised to discrete zones that exhibit hold and cold responsiveness |
|
|
Term
| What are nociceptive sensations mediated by? |
|
Definition
| mechanical, thermal and polymodal nocicpetors |
|
|
Term
| Where are mechanoceptors found |
|
Definition
| just beneath the epidermis |
|
|
Term
| Where are Meissner corpuscles found |
|
Definition
| they sit between the dermal pupillae |
|
|
Term
| Where are Merkel's discs found |
|
Definition
| alligned with the pupillae |
|
|
Term
| Where are Pacinian corpuscles found |
|
Definition
| large encapsulated endings located in the subcatenous tissue |
|
|
Term
| Where are Ruffini's corpuscles found |
|
Definition
| located deep in dermis, long axis of the corpuscle is orientated parallel to the skin |
|
|
Term
| Describe the structure of a Meissners Corpuscles |
|
Definition
comprised of looping axonal terminals and intertwined supporting cells
encapsulated |
|
|
Term
| What do Meissner corpuscles detect |
|
Definition
|
|
Term
| How much sensory innervation of the human hand do meissner corpuscles account for? |
|
Definition
|
|
Term
| Describe the structure of a Merkel disc |
|
Definition
dome structure comprised of axon terminals and merkel cells
encapsulated |
|
|
Term
| How much sensory innervation of the human hand do merkel discs account for? and where are they abundent |
|
Definition
25% of the mechanoreceptors in the skin
fingertips, lips and genetalia |
|
|
Term
| Describe the structure of a Pacinian corpuscle |
|
Definition
sensory axon surrounded by fluid filled capsule (onion shape appearance)
encapsulated |
|
|
Term
| What is the tole of the fluid filled capsule in a Pacinian corpuscle |
|
Definition
| acts as a filler and only allows transcient disturbances at high frequency (250-350Hz) to activate nerve endings |
|
|
Term
| What do Merkel disc detect |
|
Definition
|
|
Term
| What do Pacinian corpuscles detect |
|
Definition
| high frequency vibrations |
|
|
Term
| Describe the structure of a Ruffini corpuscle |
|
Definition
nerve terminals intertwined with collagen fibrils (20%)
encapsulated |
|
|
Term
| How much sensory innervation of the human hand do ruffini corpuscle account for? |
|
Definition
|
|
Term
| What do Ruffini corpuscles detect |
|
Definition
|
|
Term
| Describe the structure of free nerve endings |
|
Definition
penetrate into epithelial cells, no apparent morphological specialisation
free ramify to upper regions of the dermis and epidermis |
|
|
Term
| What do free nerve endings detect |
|
Definition
|
|
Term
|
Definition
| area of skin where stimuli evolve sensory receptor activation |
|
|
Term
| which receptors are found in punctate (discrete) zones? |
|
Definition
|
|
Term
| which receptors are found in broad zones? |
|
Definition
|
|
Term
| How do sensory receptors work? |
|
Definition
1. stimulus deforms/changes in nerve endings
2. alters the membrane permeability of the receptor membrane
3. produces a receptor (generator) potential
4. triggers an AP which travels along the axon to the CNS |
|
|
Term
| What does it mean that a sensory receptor is a pseudo-unipolar neurone |
|
Definition
axon splits into two branches
one to periphery and one to the spinal cord |
|
|
Term
| How are sensory afferents innervating somatosensory receptors classified? |
|
Definition
|
|
Term
| What does it mean if one has a large diameter |
|
Definition
rapidly conducting afferents (group I and II)
associated with low threshold mechanoreceptors |
|
|
Term
| What does it mean if one has a small diameter |
|
Definition
slow conducting afferents (group III and IV)
associated with nociceptors and thermoreceptors |
|
|
Term
| Describe the ascending locations in the mechanosensory pathway |
|
Definition
spinal cord
medulla
thalamus
somatosensory cortex |
|
|
Term
| Describe the role of first order neurones |
|
Definition
| carries sensory info from the thalamus to the cerebral cortex |
|
|
Term
| Describe the role of second order neurones |
|
Definition
| carries information from the medulla to the thalamus (and crosses over to the other side) |
|
|
Term
| Describe the role of third order neurones |
|
Definition
| carries sensory info from the thalamus to the cerebral cortex |
|
|
Term
| Where do primary efferents enter? |
|
Definition
| dorsal horn of the spinal cord |
|
|
Term
|
Definition
| sensory process that provides the signals that trigger pain |
|
|
Term
|
Definition
| feeling/perception of irritating sore stinging aching throbbing arising from a part of the body |
|
|
Term
|
Definition
| by nociceptors (not mechanoreceptors) |
|
|
Term
| Where do nociceptors have their cell bodies |
|
Definition
| in the dorsal root ganglion in the same way as other sensory receptors |
|
|
Term
| Where does the transduction of painful stimuli occur |
|
Definition
| in the free nerve endings of un-myelinated 'c' fibres ad thinly myelinated 'Ad' fibres |
|
|
Term
| Define polymodal nociceptors |
|
Definition
| respond to mechanical, thermal and chemical stimuli (some nociceptors only respond to one) |
|
|
Term
| What do mechanical nociceptors respond to |
|
Definition
|
|
Term
| What do thermal nociceptors respond to |
|
Definition
| burning heat/extreme cold |
|
|
Term
| What do chemical nociceptors respond to |
|
Definition
| histamine or other chemicals |
|
|
Term
| Where are nociceptors found |
|
Definition
the periphery as simple nerve endings
peripheral nerve fibres branches and terminates as naked un-myelinated endings in dermis |
|
|
Term
| How do pain afferents relate to histamine? |
|
Definition
| pain afferents send signals to CNS but also release signalling molecules such as substance P locally to increase the inflammatory response |
|
|
Term
| How do nociceptors differ to thermoreceptors |
|
Definition
thermoreceptors send AP until temp is too high and cannot fire anymore (or distinguish between different temperatures)
nociceptors only begin firing at the thermoreceptor threshold |
|
|
Term
| What do pain afferents release |
|
Definition
excitatory NT glutamate
synaptic terminals have vesicles containgin neuropeptides (eg substance P) |
|
|
Term
| What does the spinothalamic pathway process? |
|
Definition
| afferent inputs from peripheral mechanothermal and polymodal nociceptors |
|
|
Term
| Describe the spinothalamic pathway |
|
Definition
contralteral
sensory inputs cross at the level of spinal cord and ascend on opposite side |
|
|
Term
| Where is info relayed to from the spinal cord? |
|
Definition
| thalamus and the onto the somatosensory cortex |
|
|
Term
| what is the white bit of the eye called? |
|
Definition
|
|
Term
which muscles attach the eye ball backwards?
how many do people have? |
|
Definition
extracular muscles
5 per eye |
|
|
Term
| How many muscle fibres are there per motor neurone |
|
Definition
|
|
Term
| which is humor is on the anterior of the eye and which is more posterior? |
|
Definition
aqueous humour in front of the iris
vitreous humour |
|
|
Term
| What are the 3 areas of the retina? |
|
Definition
|
|
Term
| What vision is the macula responsible for |
|
Definition
|
|
Term
|
Definition
central/thinner region of the retina
concentrated in cone cells |
|
|
Term
|
Definition
origin of blood vessels
optic nerve axons exit eye
known as the blind spot |
|
|
Term
| What is the role of the zonule fibres? |
|
Definition
| attach the lens to the retina |
|
|
Term
| What is the function of photoreceptors and what types are there? |
|
Definition
they convert light energy to neural activity
cones and rods |
|
|
Term
| What vision are cones responsible |
|
Definition
colour vision
trichromatic
concentrated in fovea |
|
|
Term
| What vision are rods responsible |
|
Definition
achromatic
more sensitive to light
located in the periphery of retina |
|
|
Term
| What other cells are there in the retina? |
|
Definition
bipolar cells
horizontal/amacrine cells
retinal ganglion cells |
|
|
Term
| What is the role of bipolar cells |
|
Definition
| to create the direct pathway from photoreceptors to ganglion cells |
|
|
Term
| What is the role of horizontal/amacrine cells |
|
Definition
to create an indirect pathway
they are inhibitory and are therefore modulatory
'octopus' cells |
|
|
Term
| Why is dark deemed the stimulus for vision? |
|
Definition
| when it is dark a neurotransmitter is released onto bipolar cells (some ganglion) this can trigger an AP |
|
|
Term
| Describe signal transduction in the dark |
|
Definition
ion channel G proteins
cGMP allows Na+ channels to open
therefore membrane potential rises
neurotransmitter is released |
|
|
Term
| Describe signal transduction in the light |
|
Definition
| cGMP is converted to GMP and Na+ channels do not open |
|
|
Term
| Where does the optic nerve travel? |
|
Definition
| cordially to the optic chiasm |
|
|
Term
| where does most of optic information go to? |
|
Definition
| lateral geniculate nucleus which synapses with second order neurones which synapse with the striate cortex/primary visual cortex |
|
|
Term
| Where else does optic information go to? |
|
Definition
1. some crosses over (some right eye info does go to right side of brain)
2. some goes to the hypothalamus (eg regulating sleep)
3. some goes to the superior colliculus (spider reflex) |
|
|
Term
| Where do the majority of retinal ganglion cell axons terminate |
|
Definition
| lateral geniculate nucleus |
|
|
Term
|
Definition
| a series of changes in air pressure which forms a sinusoidal wave |
|
|
Term
| What makes up the outer ear |
|
Definition
Pinna (ear) made of elastic cartilage
auditory canal |
|
|
Term
| What divides the the outer and middle ear? |
|
Definition
tympanic membrane
vibrates due to changes in air pressure |
|
|
Term
| What is the role of the middle ear |
|
Definition
to magnify and amplify sound via the ossicles (bone)
x200 |
|
|
Term
|
Definition
1. once the pressure wave has come down external auditory meatus it hits the tympanic membrane
2. pressure gain from outer to middle ear is 200 fold due to ossicles
2. pressure waves are turned into nerve signals in the inner |
|
|
Term
| What are the parts of the cochlea (3) |
|
Definition
scala media
scala vestibuli
scala tympani |
|
|
Term
| What are the sensory receptors, where are they and how do they work? |
|
Definition
inner hair cells on the scala media
vibration causes the organ of corti to move and tectoral membrane distorts the cilia of the inner hair cells |
|
|
Term
| How is sound turned into nerve impulses? |
|
Definition
1.stereocillia are disturbed which produces mechanoelectrical transduction
2. the endolymph of the scala media is high in K+ and as a result opening of the channel causes the cell to depolarise
3. causes ca2+ channels to open which then transmits the signals via NT release. signals travel through the afferent nerves to the brain |
|
|
Term
| Where do sound signals go? |
|
Definition
auditory complex
located on the superior temporal gyrus in the temporal lobe of the brain |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
1.olfactory epithelium lines nasal cavity below cribiform plate
2.odorants enter nasal cavity and dissolve in mucus secretion
3.dissolved odorants bind to cilia that project into nasal cavity |
|
|
Term
| How many fluid filled chambers is the cochlea made up of? |
|
Definition
|
|
Term
| Describe the mechanism for olfaction transduction |
|
Definition
1. odorants bind to receptors on cilia
2. activation of G proteins and production of cAMP
3. cAMP binds to and opens cation (Ca2+ and Na+) channels
4. opening of Cl- channels
5. generates depolarisation |
|
|
Term
| State the organs involved in taste |
|
Definition
mainly tongue
also: pharynx, palate and epiglottis |
|
|
Term
| State the taste sensation factors (3) |
|
Definition
food odour/aromas
visual appearance
texture |
|
|
Term
| What are papillae and name the 3 types |
|
Definition
taste sensitive structures on the tongue
circumvallate
foliate
fungiform |
|
|
Term
| Describe circumvallate papillae |
|
Definition
largest
contain many thousand tastebuds
located at posterior |
|
|
Term
| Describe foliate papillae |
|
Definition
elongated structure
contain hundreds of tastebuds
lie along the posterior lateral edge |
|
|
Term
| Describe fungiform papillae |
|
Definition
smallest
contain one or two tastebuds
widespread across the anterior portion and tip of tongue |
|
|
Term
| Describe the mechanism for taste transduction |
|
Definition
1. dissolved molecules interact with receptors
2. triggers membrane depolarisation and AP firing
3. accompanied by increase in intracellular calcium which initiates transmitter release |
|
|
Term
| In taste, where do first order neurones project to? |
|
Definition
|
|
Term
| In taste, where do second order neurones project to? |
|
Definition
|
|
Term
| In taste, where do third order neurones project to? |
|
Definition
|
|
Term
| What must be rhythm be to be classified at circadian? |
|
Definition
1. repeated once a day
2. persist in the absence of external cues
3. be able to be adjusted to match local times |
|
|
Term
|
Definition
| caused by altered light dark cycle and the body trying to put it back into pattern (takes a couple of days). Impairs physiological and psychological health and induced stress. |
|
|
Term
| What causes jet lag to differ? |
|
Definition
|
|
Term
| What is the molecular basis of jet lag? |
|
Definition
- gene expression in the suprachiasmatic nucleus (SCN) changes when unexpected flashes of light occur
- negative feedback system in nucleus slows down adaptation |
|
|
Term
|
Definition
| in the hypothalamus and contains lots of interneurones |
|
|
Term
| What are retinal ganglion cells? |
|
Definition
| photoreceptors for detecting changes in light levels |
|
|
Term
| What does the pineal gland produce? |
|
Definition
|
|
Term
| What parameters are there for melatonin? |
|
Definition
1. body temperature
2. darkness
3. alterness
4. cortisol
5. growth hormone
6. potassium |
|
|
Term
| How does body temperature relate to sleep? |
|
Definition
| body temperature drops when you are asleep as melatonin increases |
|
|
Term
| How does melatonin change related to darkness? |
|
Definition
| melatonin increases as surroundings become more dark |
|
|
Term
| What else changes as melatonin increases? |
|
Definition
alertness decreases
cortisol increases overnight
growth hormone increases overnight
potassium levels are higher during the day |
|
|
Term
|
Definition
|
|
Term
| What does stimulation of midline brainstem areas alter? |
|
Definition
| cortisol EEG from non-REM to alert/awake form |
|
|
Term
| When are cholinergic neurones in pons/midbrain border active? |
|
Definition
waking and REM sleep
inactive during non-REM sleep |
|
|
Term
| Which systems are activated in wakefulness? |
|
Definition
- noradrenaline, serotonin and histamine
- neural systems |
|
|
Term
|
Definition
| electrodes are placed on scalp and neural (electricity) activity measured |
|
|
Term
|
Definition
| readily reversible state of reduced responsiveness to and interaction with, the environment |
|
|
Term
| Which sleep stage is the most prominent and what occurs then? |
|
Definition
Non-REM sleep – slow-wave stage is most
prominent
During non-REM sleep, physiological functions
decrease (muscle tone, heart rate, temperature) |
|
|
Term
| What also occurs as subject moves through sleep stages? |
|
Definition
|
|
Term
| What occurs after IV stage? |
|
Definition
| subjects enter Rapid Eye Movement stage |
|
|
Term
| How do EEG recordings during REM sleep compare to awake state? |
|
Definition
|
|
Term
| What occurs during REM sleep? |
|
Definition
1. Physiological functions increase almost to “awake” levels, energy consumption of brain is higher.
2. Lower motor neurones in spinal cord are inhibited:
– paralysis of large muscle groups
– BUT Muscles of eye movement & inner eye are strikingly
active
3. Incoming sensory stimuli are also blocked
– Don’t reach the cortex |
|
|
Term
| How long do subjects spend in REM sleep? |
|
Definition
| Subjects spend ~10 minutes in REM sleep, then brain usually goes back through stages I-IV |
|
|
Term
|
Definition
Sleep walking
– Peaks at 11 yrs, 40% will have suffered
– Stage 4 non-REM sleep
– Hard to wake up, slow wave sleep |
|
|
Term
|
Definition
Sleep talking
– Most people will have
– Garbled and non-sensical |
|
|
Term
|
Definition
– 5-7 yrs
– Not nightmares (REM)
– Stage 3 & 4 non-REM |
|
|
Term
|
Definition
• Ecological: quiet time to avoid predation
• Metabolic: reduces energy expenditure,
• Learning: memory consolidation or erasure |
|
|
Term
| What happens if we are sleep deprived? |
|
Definition
– Increased tension
– Increased irritability
– Depression
– Confusion |
|
|
Term
|
Definition
| process of acquiring new information |
|
|
Term
|
Definition
| persistence of learning in a state that can be revealed at a later time |
|
|
Term
|
Definition
| Processing of incoming information to be stored |
|
|
Term
|
Definition
| The result of acquisition and consolidation; creation and maintenance of a permanent record |
|
|
Term
|
Definition
| Utilisation of stored information to create a conscious representation or to execute a learned behaviour |
|
|
Term
| What is memory split into? |
|
Definition
| short term/working memory and long term memory |
|
|
Term
| What is long term memory split into? |
|
Definition
Declarative: knowledge we have conscious access to, including personal and world knowledge.
Non-declarative: or procedural memory. This is the other part of memory that we are less familiar with – the unconscious part, it is the memory of behaviours, skills and emotions. |
|
|
Term
| What is declarative memory split into? |
|
Definition
Episodic: events
Semantic: facts |
|
|
Term
| What is non-declarative memory split into? |
|
Definition
Priming
Skills and habits
Associative conditioning |
|
|
Term
| What is associative conditioning |
|
Definition
| skeletal musculature and emotional response |
|
|
Term
| What is the shortest term memory? |
|
Definition
Sensory (immediate) memory
Lifetime of milliseconds to seconds
E.g. recalling a sentence from a conversation you are not paying attention to
Visual: iconic memory; audition: echoic memory |
|
|
Term
| How long does short term memory last and what is its capacity? |
|
Definition
Lifetime of seconds to hours
E.g. remembering a phone number given by a friend before trying to dial it
Typically around 7 items (digit span) |
|
|
Term
| How long does long term memory last and what is its capacity? |
|
Definition
Lifetime of days to years
E.g. recalling an event from childhood or last weekend. |
|
|
Term
| Therefore, where does sensory information go and what happens after each stage? |
|
Definition
1. sensory memory
2. short term memory
3. long term memory
information is lost |
|
|
Term
| How do short term memories become long term memories? |
|
Definition
rehearsal (otherwise lost within seconds)
then encoding in the hippocampus |
|
|
Term
| What happens if long term memory is not retrieved back into short term memory? |
|
Definition
|
|
Term
| Describe the anatomy involved in the working memory model |
|
Definition
3 brain regions involed
central executive is in charge
2 subordinate systems called visuospatial sketchpad and phonological loop |
|
|
Term
| What occurs in the visuospatial sketchpad? |
|
Definition
visual information is processed and played around with
information storage in visual or visuospatial codes. |
|
|
Term
| What occurs in the phonological loop? |
|
Definition
where auditory information is processed
mechanism for acoustically coding information in working memory |
|
|
Term
| What occurs in the central executive? |
|
Definition
| the bit of the brain where the information initially comes in to, and then eventually gets sent out from. |
|
|
Term
| Where in the brain is the phonological loop? |
|
Definition
Left supramarginal gyrus (area 40)
Left premotor region (area 6 |
|
|
Term
| Where in the brain is the visuospatial sketchpad? |
|
Definition
| Parieto-occipital regions of both hemispheres affect visuospatial performance (right hemisphere dominant). |
|
|
Term
| What are the visuospatial sketchpad and the phonological loop distinct from? |
|
Definition
|
|
Term
| What are flashbulb memories? |
|
Definition
a type of long term memory that you remember very clearly – although not always that accurately!
emotionally charged |
|
|
Term
| Where in the brain is long term memory formed? |
|
Definition
Hippocampus
Mammillary body
Dorsal thalamus
Rhinal cortex |
|
|
Term
| Where in the brain is long term memory stored? |
|
Definition
Neocortex
Frontal cortices on dorsolateral and anterolateral aspects |
|
|
Term
| What does the hippocampus resemble? |
|
Definition
|
|
Term
| How is olfaction and memory linked? What structures in the brain are related? |
|
Definition
certain smells invoke memories from years ago
Olfactory cortex is linked to hippocampus and amygdala, both important in memory |
|
|
Term
| How is music and memory linked? |
|
Definition
| musical training, or listening to music, are thought to improve memory |
|
|
Term
| Why does memory function decline as a part of the ageing process? |
|
Definition
| There is a decrease in the number of synaptic connections with age consistent with the idea that memories may be lost |
|
|
Term
| What is non-associative procedural learning? |
|
Definition
| change in motor response after repeated presentation of a stimulus. |
|
|
Term
| What are the two types of non-associative procedural learning? |
|
Definition
a) Habituation –decrease in motor response.
b) Sensitisation – increase in motor response. |
|
|
Term
| What are the two types of associative procedural learning? |
|
Definition
a) Classical conditioning change in passive motor response after learned association between two stimuli (e.g. Pavlov’s dogs).
b) Instrumental or operant conditioning change in active motor response after association between motor action and reward. |
|
|
Term
| Name the brain systems underlying procedural long-term memory |
|
Definition
Basal ganglia
Prefrontal cortex
Amygdala
Sensory association cortex
Cerebellum |
|
|
Term
| Where does motor learning happen? |
|
Definition
|
|
Term
| Where does emotional learning happen? |
|
Definition
|
|
Term
| Define anterograde amnesia |
|
Definition
| Inability to establish new memories |
|
|
Term
| Define retrograde amnesia |
|
Definition
| Difficulty in retrieving memories |
|
|
Term
| What is synaptic plasticity? |
|
Definition
| Synaptic plasticity is the ability of synapses to strengthen or weaken over time, in response to increases or decreases in their activity |
|
|
Term
| How are memories encoded? |
|
Definition
increase the strength of a synapse through long term potentation
in the hippocampus |
|
|
Term
| What is the mechanism behind long term potentiation? |
|
Definition
Increased number of vesicles and neurotransmitter
Increased number of AMPA-R
Increased surface area of the synaptic cleft |
|
|
Term
| Where does cognition occur? |
|
Definition
| in association cortices found in the frontal, temporal and parietal lobes. |
|
|
Term
| Where do association cortices receive input from? |
|
Definition
- directly from other cortical areas
- highly processed information from primary sensory / motor areas via thalamic nuclei
- subcortical inputs |
|
|
Term
| What other cortical areas does association cortices directly receive input from? |
|
Definition
directly from other cortical areas:
- motor and premotor cortices
- other primary and secondary sensory cortical regions
Remember you have two parts of your brain so will receive twice the input you think. |
|
|
Term
| Define ipsilateral cortico-cortical connections |
|
Definition
| input comes from the same hemisphere of brain |
|
|
Term
| Define interhemispheric cortico-cortical connections |
|
Definition
| connections cross the corpus collosum and join information from both hemispheres |
|
|
Term
| Which thalamic are involved and which cortices do they work with? |
|
Definition
Pulvinar nucleus (parietal association cortex)
Medial dorsal nucleus (frontal association cortex)
(Anterior and ventral anterior nuclei) |
|
|
Term
| Where does association cortices receive subcortical inputs from? |
|
Definition
- Dopaminergic neurones in the midbrain
- Noradrenergic / serotonergic neurones in the reticular formation
- Cholinergic neurones in the brainstem and basal forebrain |
|
|
Term
|
Definition
| The state of selectively processing simultaneous sources of information |
|
|
Term
| What does attention involve? |
|
Definition
| Involves preferential processing of sensory information (e.g. visual, auditory) |
|
|
Term
| What does attention allow? |
|
Definition
- Allows covert shifting (e.g. listening to a conversation whilst engaged in another).
- Allows increased reaction time to stimuli (e.g. faster braking when paying attention to the car in front). |
|
|
Term
| What is attention subject to? |
|
Definition
| Subject to external influences (e.g. a loud noise will shift our attention away from the task at hand). |
|
|
Term
| What is ADHD characterised by? |
|
Definition
| by inattention, hyperactivity, impulsiveness |
|
|
Term
| What does imaging suggest about ADHD sufferers? |
|
Definition
| Imaging suggests that prefrontal cortex and basal ganglia are smaller in sufferers |
|
|
Term
| What causes contralateral neglect syndrome? |
|
Definition
| Caused by lesion to right parietal cortex |
|
|
Term
| What are contralateral neglect syndrome sufferers unable to do? |
|
Definition
- attend to objects in a portion of space
- to attend to stimuli presented to the side of the body (or visual space) opposite the lesion |
|
|
Term
| What causes Balint's syndrome? |
|
Definition
| lesion to parietal cortex |
|
|
Term
| What are the effects of Balint's syndrome? |
|
Definition
Triad of visuospatial deficits:
- Simultanagnosia (inability to perceive visual scene as a whole)
- Optic ataxia (deficit in visually guided reaching)
- Ocular apraxia (difficulty in voluntary scanning of visual scenes) |
|
|
Term
|
Definition
| inability to percieve parts of a visual scene as a whole |
|
|
Term
|
Definition
| deficits in visually guided reaching |
|
|
Term
|
Definition
| difficulty in voluntary scanning of visual scenes |
|
|
Term
| Which association cortex mediates attention? |
|
Definition
| the parietal association cortex |
|
|
Term
|
Definition
|
|
Term
| Which parietal cortex is predominately responsible for attention? |
|
Definition
|
|
Term
| What does covert shifting mean? |
|
Definition
| shifting your attention without appearing to do so |
|
|
Term
| What does Balint's syndrome cause? |
|
Definition
|
|
Term
| What is emotion made up of? |
|
Definition
| feelings, expressive behaviour and physiological changes |
|
|
Term
| How is an emotion generated? |
|
Definition
Evaluation of sensory input
Conscious / unconscious experience of a feeling
Expression of behavioural and physiological response |
|
|
Term
| What are the 3 components of an emotional response? give examples |
|
Definition
Behavioural E.g. muscular movements (smile, frown etc).
Autonomic E.g. Sympathetic / parasympathetic activity
Hormonal E.g. Adrenaline release |
|
|
Term
| Which brain system is involved in emotional processing? |
|
Definition
|
|
Term
| Which structures have clear roles in emotional processing? |
|
Definition
Amygdala
Orbitofrontal cortex
Cingulate gyrus / thalamus / ventral basal ganglia |
|
|
Term
| Where is the amygdala located? |
|
Definition
| deep in the brain's medial temporal lobe |
|
|
Term
| What would you be unable to recognise if you have damage to your amygdala? |
|
Definition
fear
often confused with surprise |
|
|
Term
| Which nervous system is involved in expression of emotion? |
|
Definition
|
|
Term
| What is the hippocampus involved in? |
|
Definition
|
|
Term
| Bilateral loss of the amygdala results in... |
|
Definition
| ...loss of ability to recognise fear |
|
|
Term
| The orbitofrontal cortex is involved in... |
|
Definition
| ...emotional decision making |
|
|
Term
| How many universal facial expression are humans able to recognise? |
|
Definition
|
|
Term
| Which organs acts as the source of air for speech? |
|
Definition
|
|
Term
| Which organs acts as the source of sound for speech? |
|
Definition
|
|
Term
| Which organs modify/filter speech? |
|
Definition
| Pharynx, oral cavity (incl tongue, teeth, lips) and nasal cavity |
|
|
Term
| Which hemisphere is associated with language? |
|
Definition
left
however, it is not unknown for someone to favour the right area |
|
|
Term
|
Definition
| left frontal cortex; involved in language production. |
|
|
Term
|
Definition
| left temporal cortex; involved in understanding spoken language. |
|
|
Term
|
Definition
| damage to specific brain regions which compromises language functions, without affecting sensory / motor processing. |
|
|
Term
|
Definition
| physical production of speech |
|
|
Term
| What is Wernicke's aphasia? |
|
Definition
|
|
Term
| What is conduction aphasia? |
|
Definition
| difficulty repeating words (arise from lesions to pathways connecting language centres) |
|
|
Term
| Which cortex is very important in overseeing many complex activities and be able to make decisions? |
|
Definition
| prefrontal cortex (Dorsolateral PFC and Ventromedial PFC) |
|
|
Term
| What are the functions of the Dorsolateral prefrontal cortex? |
|
Definition
- initiating and shifting behaviour
- inhibiting behaviour
- stimulating behavioural consequences |
|
|
Term
| What are the functions of the ventromedial prefrontal cortex? |
|
Definition
- Inhibition of socially inappropriate behaviour
- Sensitivity to the consequences of action |
|
|
Term
| Does the brain control the muscle directly? |
|
Definition
| No, the spinal cord is involved. |
|
|
Term
|
Definition
|
|
Term
| Describe spinal motor output |
|
Definition
| alpha motoneurones to muscles |
|
|
Term
| What is each motoneurone associated with? |
|
Definition
| muscle fibres forming a functional entity called the motor unit |
|
|
Term
| What do motor units vary in? |
|
Definition
size
amount of tension produced
speed of contraction
degree of fatigability. |
|
|
Term
| Where are motoneurones innervating axial musculature located? |
|
Definition
|
|
Term
| Where are motoneurones innervating distal musculature located? |
|
Definition
|
|
Term
| What makes up a motor unit? |
|
Definition
4-5 muscle fibres innervated by a single motor neurone
(motoneurone + innervated muscle fibre) |
|
|
Term
| Describe the events that follow when an action potential arrives a at a neuromuscular junction |
|
Definition
1. it causes vesicle to dock
2. The vesicles then release the neurotransmitter acetylcholine into the synaptic cleft
3. This then stimulates nicotinic receptors on the muscle fibre with the end result that myosin contracts the muscle fibre |
|
|
Term
|
Definition
|
|
Term
|
Definition
| A motor pool consists of all of the motor neurons that innervate a single muscle |
|
|
Term
| How are the lumbar motorpools arranged? |
|
Definition
in a rostrocaudal manner
hip: occupies the whole length of the lumbar cord
knee: most of it
ankle: lower lumbosacral segments |
|
|
Term
| What is the muscle spindle? |
|
Definition
the sensory apparatus of the muscle
Muscle spindles are sensory receptors that primarily detect changes in the length of this muscle (Intrafusal muscle fibers). |
|
|
Term
| Where are muscle fibres found? |
|
Definition
within the belly of a muscle
lies parallel to muscle fibres |
|
|
Term
| What do spindle fibres contribute to? |
|
Definition
proprioception
the detection of position and movement of body in space |
|
|
Term
| What do spindle fibres enable? |
|
Definition
| regulation of muscle contraction and precisely matches force generation to motor task |
|
|
Term
| What routine neurological examination demonstrates the effects of spindle fibres? |
|
Definition
when you tap the patellar tendon and stretches the muscle leading to muscle contraction
Muscles are always under some degree of stretch so this reflex is responsible for steady level of tension in muscle called muscle tone. |
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Term
| What are extrafusal muscle fibres? |
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Definition
| the skeletal standard muscle fibers that form bulk of muscle and generate muscle tension |
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Term
| What are extrafusal muscles innervated by? |
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Definition
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Term
| What are intrafusal muscle fibres? |
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Definition
| (spindles) have a sensory function and do not generate tension. |
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Term
| What are intrafusal muscles innervated by? |
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Definition
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Term
| Describe muscle contraction in terms of spindle fibre sensitivity |
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Definition
1. Muscle relaxed, Spindle fibre sensitive to stretch of muscle
2. Muscle contracted, slackened spindle fibre not sensitive to stretch of muscle
3. Muscle contracted, contracted spindle fibre sensitive to stretch of muscle |
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Term
| Name the two sensory afferents that emerge from the intrafusal system |
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Definition
| sensory afferents Ia and II |
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Term
| Describe the afferents associated with low threshold mechanoreceptors |
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Definition
| Large diameter, rapidly conducting afferents (I/II) |
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Term
| Describe the afferents associated with nociceptors and thermoreceptors |
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Definition
| Small diameter, slow conducting afferents (III/IV) |
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Term
| How is conduction velocity related to axon diameter |
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Definition
| Conduction velocity is positively correlated with axon diameter. |
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Term
| What effect does a contracting muscle have on a tendon? |
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Definition
| When the muscle contracts the force acts directly on the tendon, and thus an increase in tension in the collagen fibres and in the golgi tendon organ. |
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Term
| What is the Golgi tendon organ? |
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Definition
| The Golgi tendon organ is a mechanoreceptor that detects changes in muscle tension, as when the muscle contracts the force acts directly on the tendon. |
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Term
| What is the function of the GTO? |
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Definition
Acts like a strain gauge i.e. monitors muscle tension & the force of contraction.
Contributes to proprioception i.e. detection of position and movement of body in space . |
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Term
| Where is the GTO found and what is it innervated by? |
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Definition
Lies in series with muscle fibres.
Acts like a strain gauge i.e. monitors muscle tension & the force of contraction. |
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Term
| Describe the sensory input (afferents) from muscle spindles |
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Definition
Primary afferent, group Ia (senses stretch and rate of change in stretch),
Secondary afferent, group II (stretch only)
Group III and above are finer than the two above (nociceptive from muscle) |
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Term
| Describe the sensory input (afferents) from tendon organs |
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Definition
| group Ib (signal force change in the muscle) |
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Term
| Describe the spinal somatic reflex pathway to flexors |
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Definition
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Term
| Describe the spinal somatic reflex pathway to extensors |
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Definition
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Term
| Describe the pathway for a monosynaptic reflex |
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Definition
| Stretch reflex: -> Muscle spindle Ia afferent -> homonymous alpha Motoneurone -> OUTPUT |
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Term
| Describe the pathway for a polysynaptic reflex |
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Definition
| Crossed Extensor reflex (FRA reflex): -> Sensory afferent -> Interneuron -> motoneurone -> OUTPUT |
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Term
| What are 3 characteristics of neurological diseases? |
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Definition
irreversible
loss of neurones
progressive |
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Term
| Name 4 neurological disorders? |
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Definition
Alzheimer’s disease
Multiple sclerosis
Parkinson’s disease
Huntington’s disease |
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Term
| What are the early symptoms of Alzheimers? |
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Definition
Short term memory
Disorientation - time then place
Difficulty with words, names, numbers
Clumsiness
Visuospatial orientation (gets lost) |
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Term
| What are the later symptoms of Alzheimers? |
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Definition
Loss of social skills
psychosis + paranoia/hallucinations/delusions
bradykinesia/rigidity |
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Term
| What are the latest symptoms of Alzheimers? |
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Definition
Mutism
Incontinence
Bedridden |
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Term
| How does a brain with Alzheimers compare to one without? |
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Definition
Smaller
Wider sulci and narrowed gyri
central sulci much wider |
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Term
| How do the ventricles change with Alzheimers? |
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Definition
| the fluid filled spaces within the brain widens as the brain matter gets smaller |
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Term
| Which lobe is affected in particular with Alzheimers? |
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Definition
temporal lobe
hippocampus (short term memory)
insula (language capabilities) |
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Term
| What is measured in scans during Alzhiemers? |
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Definition
glucose uptake
measures metabolic activity and working neurones |
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Term
| What do Alzhiemers patients experience first? |
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Definition
| mild cognitive impairement |
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Term
| What forms in the middle frontal cortex of Alzheimers patients? |
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Definition
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Term
| What forms in the hippocampal sector of Alzheimers patients? |
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Definition
| Neurofibrillary tangles – hyperphosphorylated tau protein |
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Term
| Which pathways are particularly affected in Alzheimers? |
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Definition
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Term
| What is the current treatment for Alzheimers? |
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Definition
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Term
| What is the effect of AChE inhibitors? |
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Definition
Increases ACh levels
May slow progression
May improve cognition (‘nootropic effect’) |
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Term
| What are the symptoms of multiple sclerosis? |
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Definition
Sensory changes
Muscle weakness
Coordination and balance
Speech
Swallowing
Visual
Fatigue,
Pain
Incontinence
Cognitive impairment
Depression
Mood swings |
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Term
| What are the different forms of progression of MS? from most severe to lest severe |
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Definition
progressive-relapsing multiple sclerosis
secondary progressive multiple sclerosis
primary progressive multiple sclerosis
relapsing-remitting multiple sclerosis |
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Term
| Describe progressive-relapsing multiple sclerosis |
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Definition
| steady decline since onset with superimposed attacks |
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Term
| Describe secondary progressive multiple sclerosis |
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Definition
| initial relapsing-remitting MS that suddenly begins to have decline without periods of remission |
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Term
| Describe primary progressive multiple sclerosis |
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Definition
| steady increase in disability without attacks |
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Term
| Describe relapsing-remitting multiple sclerosis |
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Definition
| unpredictable attacks which may or may not leave permanent deficits by periods of remission |
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Term
| How does the CNS change with MS? |
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Definition
| MRI scans show reduction in total brain volume and therefore increase in ventricular size |
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Term
|
Definition
autoimmune disorder
the body produces antibodies against their own bodies (specifically attack oligodendrocytes that produce myelin sheath) |
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Term
| What are the symptoms of Parkinson's? |
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Definition
Tremor
Rigidity
Speech
Micrographia
Akinesia
Postural changes
Stoop
Shuffling |
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Term
| What structure does PD affect specifically? |
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Definition
| substantia nigra (which diminishes) |
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Term
| Describe the pathway affected by PD |
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Definition
1. nerve cells project to striatum (dopaminergic from substantia nigra)
2. these project to the thalamus
3. these project to motor cortex
4. these project to skeletal muscle via spinal cord |
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Term
| How is Huntington's disease different? |
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Definition
inherited
autosomal dominant (only one parent needs it to give you a 50% chance) |
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Term
| Which protein is involved in Huntingtons? |
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Definition
Huntingtin
the more gultamine repeats you have the earlier it occurs and more rapidly it occurs |
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Term
| What are the symptoms of HD? and what do they lead to? |
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Definition
Irritability, Moodiness, Antisocial behaviour >>> dementia
Fidgeting and restlessness >>> gross choreiform movements |
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Term
| Where are neurones lost in HD? |
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Definition
cerebral cortex
corpus striatum |
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Term
| What neuronic pathways are affected? |
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Definition
| GABAergic and cholinergic |
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Term
| What disorders of the central nervous systems are there? |
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Definition
Schizophrenia
Bipolar disorder
Depression
Anxiety disorders |
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Term
| What are the positive symptoms of schizophrenia? |
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Definition
PSYCHOSIS
Hallucinations
Delusions
Thought disorder |
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Term
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Definition
sensory perception with no external stimulus
all senses
often voices |
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Term
| What are delusions and what types are there? |
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Definition
often paranoid
primary delusions spontaneous, sudden
secondary delusions reflect situation |
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Term
| How can psychosis affect thought disorder? |
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Definition
conscious thought
loosening of associations
speech and language |
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Term
| What are the negative symptoms of schizophrenia? |
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Definition
Social withdrawal
Flattening of emotional responses
Anhedonia
Disinterest in everyday tasks
Cognitive deficits e.g. Attention, memory
Guilt, depression, anxiety, self harm
Can lead to suicide attempts (50%)
10% successful |
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Term
| How does schizophrenia affect younger patients? |
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Definition
| more positive symptoms, relapsing and remitting |
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Term
| How does schizophrenia affect older patients? |
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Definition
| more negative symptoms, chronic and progressive |
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Term
| Is schizophrenia genetic? |
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Definition
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Term
| What are the environmental causes of schizophrenia? |
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Definition
Maternal viral infection
Maternal famine
Maternal stress
Cannabis consumption
Winter/spring birth
Urbanisation |
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Term
| Describe the dopamine turnover hypothesis that explains schizophrenia |
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Definition
Increased DA activity leads to psychosis
DA antagonists or partial agonists antipsychotic
Mesolimbic pathway ↑ – positive symptoms
Mesocortical pathway ↓ – negative symptoms |
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Term
| What is the new hypothesis related to schizophrenia? |
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Definition
More recently – NMDA receptors also involved
NMDA hypofunction hypothesis |
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Term
| How does the brain change from schizophrenia? |
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Definition
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Term
| What is bipolar characterised by? |
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Definition
| mood swings (mania and depression) |
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Term
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Definition
Increased energy, activity, and restlessness
Excessively “high,” overly good, euphoric mood
Extreme irritability
Racing thoughts and talking very fast, jumping from one idea to another
Lack concentration
Insomnia
Unrealistic beliefs in one’s abilities and powers
Poor judgment
Spending sprees
A lasting period of behavior that is different from usual
Increased sexual drive
Abuse of drugs, particularly cocaine, alcohol, and sleeping medications
Provocative, intrusive, or aggressive behavior
Denial that anything is wrong |
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Term
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Definition
Lasting sad, anxious, or empty mood
Feelings of hopelessness or pessimism
Feelings of guilt, worthlessness, or helplessness
Loss of interest or pleasure in activities once enjoyed, including sex
Decreased energy, a feeling of fatigue or of being “slowed down”
Difficulty concentrating, remembering, making decisions
Restlessness or irritability
Sleeping too much, or can’t sleep
Change in appetite and/or unintended weight loss or gain
Chronic pain or other persistent bodily symptoms that are not caused by physical illness or injury
Thoughts of death or suicide, or suicide attempts |
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Term
| What are the causes of bipolar? |
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Definition
Some evidence for genetics, e.g. Twin studies
Probably polygenic with environmental factors
5-HT, DA and Glu transmitter systems affected
Cell growth and/or maintenance pathways affected e.g. BDNF |
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Term
| What are the emotional symptoms of depression? |
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Definition
Low mood, negative thoughts, misery, pessimism, apathy
Low self esteem
Indecisiveness
Anhedonia |
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Term
| What are the biological symptoms of depression? |
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Definition
Retardation of thought, action
Loss of libido
Sleep, appetite disturbance |
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Term
| What is thought to be the cause of depression? |
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Definition
Caused by decreased function of 5-HT and NA systems.
Evidence provided by testing drugs and measuring their effects |
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Term
| Describe cortisol plasma levels in the depressed |
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Definition
High plasma cortisol levels (doesnt fall following dexamethasone)
Corticotrophin-releasing hormone (CRH) levels high and CRH injection into the brain causes depression symptoms |
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Term
| What are the effects of depression on the actual brain? |
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Definition
| Neurones lost in hippocampus, prefrontal cortex. |
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Term
| What is the evidence of neurone loss in hippocampus, prefrontal cortex? |
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Definition
Vetricular enlargement
Hippocampal shrinkage
Prefrontal atrophy
Reduced neuronal activity in same |
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Term
| What 3 ways are used to treat depression? |
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Definition
- monoamine uptake inhibition
- monoamine receptor antagonists
- monoamine oxidase inhibitors |
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Term
| Give examples of monoamine uptake inhibitors |
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Definition
Tricyclic antidepressants (e.g. imipramine)
SSRIs (e.g. fluoxetine)
SNRIs (e.g. venlaflaxine)
NRIs (e.g. bupropion) |
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Term
| Give examples of monoamine receptor antagonists |
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Definition
Non-selective blockers of especially α2 and 5-HT2
E.g. trazodone |
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Term
| Give examples of monoamine oxidase inhibitors |
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Definition
Irreversible, non-competitive, non-selective for MOA-A/B (e.g. phenelzine)
Reversible, MAO-A selective (e.g. moclobemide) |
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Term
| What are the fear responses of anxiety disorders? |
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Definition
Defensive behaviours
Autonomic reflexes
Arousal/alertness
Corticosteroid secretion
Negative emotions |
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Term
| Name the 5 anxiety disorders with a very brief description |
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Definition
Generalised anxiety disorder
ongoing generalised anxiety
Obsessive compulsive disorder
compulsive ritualistic irrational behaviour
Panic disorder
sudden overwhelming attack
Post-traumatic stress disorder
recall of past experiences
Social phobia
fear of others |
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Term
| What is the treatment for anxiety disorders and what do they affect? |
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Definition
Benzodiazepines, barbiturates
SSRIs/SNRIs
Buspirone
Affect GABA/5HT systems |
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