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Test 4 Brain
Brittin
115
Anatomy
Undergraduate 2
11/29/2011

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Term
Membrane Potential
Definition
All calls produce & maintain a difference in electric charge across their membrane.
Term
How do cells control membrane potential?
Definition
By controlling the distribution of ions across the membrane.
Term
What do ordinary cells use membrane potential for?
Definition
to aid in transport across the membrane.
Term
Which cells can change their membrane potential?
Definition
Nerve and muscle cells-- is crutial to their function
Term
For a neuron, what is the resting membrane potential?
Definition
-70 mV ((70 mV more negative inside)
Term
Hyperpolarized?
Definition
More negative inside than -70mV
Term
Hypopolarized?
Definition
Less negaive inside than -70mV
Term
Depolarized
Definition
if the charge difference goes to 0 in the neuron
Term
How can you monitor the changes inside the neuron?
Definition
w/ micro electrodes- one inside, one outside and an oscilioscope
Term
Na concentration in neurons?
K concentration in neurons?
Definition
20X higher outside than inside
40X highter inside than outside
Term
3 Factors that operate to produce and maintain the difference in ion concentration:
Definition
1) "fixed" negative charges w/i cell draw positive ions in
2) The membrane is by nature more permeable to K therefore more k enters
3) the Na/K pump-an ion pumping protein in cell membranes [pushes 3 Na out for every 2 K it pulls in]
Term
Do Na and K have their own gates?
Definition
yes
Term
At resting potential what gates are shut?
Definition
Na
Term
At resting potential what gates are slightly open?
Definition
K
Term
Does Na or K slowly diffuse out keeping the resting potential stable?
Definition
K
Term
If a neuron is slightly hypopolarized to -55mV what will happen?
Definition
It will hit its threshold potential causing the Na gates to open wide. The Na rushes in and the neuron depolarizes so much that the charge reverses to 30mV.
Term
What is the change from -55mV to 30mV called?
Definition
Action Potential
Term
As soon as the neuron hits 30mV what happens?
Definition
The K gates open wide and K rushes out and the neuron repolarized. So much that it overpolarizes to -90-100mV.
Term
When a neuron overpolarizes what is it called?
Definition
K equilibrium potential-K gate closes and resting point is gradually restored.
Term
Action potentials are "--------- or -------------"
Definition
1. All
2. None
Term
Are action potentials always the same strength?
Definition
Yes
Term
Will an increased stimulus increase the the strength of an action potential?
Definition
No
Term
During what period can a neuron not be forced to produce another action potential? Why?
Definition
Absolute Refractory Period

B/c Na gates are already open or blocked and unusable
Term
During what period can a neuron be pushed to produce another action potential? why?
Definition
Relative Refractory Period- BUT a stronger that usual stimulus is needed because the neuron is hyperpolarized
Term
How much time exists between Resting potential to AP to resting poential?
Definition
3 milliseconds
Term
What does an increased stimulus intensity effect?
Definition
Increased neuron and effector activity
Term
What 2 ways does the stimulus intensity effect neuron and effectors?
Definition
1) Increae the frequency of AP's on a nerve fiber [but they can't get closer than the Absoult Refractory Period]
2)Recructement-since different neuron and effector cells have different thresholds. As stimulus strength increases, activity inccreases as more hit their threshold. This allows graded responses. > graded contraction of skeletal muscles
Term
What is a cable property?
Definition
the ability to conduct electric charge
Term
Are the cable proterties of nerve fibers good? Why?
Definition
No
1) Fixed charges w/i fiber resist flow
2) Membrane is "leaky"-charge leaks off w/ distance
Term
What is the effection conduction distance alone a fiber?
Definition
1-2mm
Term
What happens as an impulse travels along a nerve fiber?
Definition
It propeogates as a series of AP's generated one after another along the fiber.
Term
What is better pure conduction or propogating? Why?
Definition
Propogation b/c since AP's are all or none the last in a series will be just as strong as the first regardless of distance.--no loss of signal strendth
Term
The process of conduction differs depending on what?
Definition
Whether the fibers are unmyelinated or myelinated
Term
What is the difference between unmyelinated and myelinated fibers?
Definition
1)un-AP's occur at every suitable site alone the fiber. Since these sites are just fraction of a micrometer apart and since each AP is a seperate event and the last must end before the nest starts---Slows conduction
2)My-In these, ions can only cross the membrane at the gaps in the sheath(Nodes of Ranvier) These are 1mm apart. Thus that requires fewer AP's----Speeds Conduction
Term
What 2 factors effect inpulse speed?
Definition
Type of fiber-Myelinated or un
Diameter-Large=faster
Term
Synapses connect --------to----------- OR -------to-------------.
Definition
1. neuron
2. Neuron
3. Neuron
4. effector cell
Term
4 structure types of synapses:
Definition
1. axodendritic- connects bouton to dendrite
2. Axosomatic-connects bouton to cell body
3. Axoaxonic- connects bouton to axon
4. Dendrodendritic- dendrite to dendrite
Term
Function types of synapses:
Definition
1)Electrical-Dendordendritic type-either direction-RARE (certain areas of brain) The neurons are coupled by special gap junction that form direct cell to cell ion channels.

2)Chemical-Axodendritic, axosomatic, and axoaxonic-one way (bouton to next cell)-Rely on neurotransmitters b/c there is a gap b/w the cells(=synapic cleft) that must be jumped chemically(ACh)
Term
What is the hypolarization produced by an excitatory neurotransmitter called?
Definition
excitatiory Postsynapitc Potential (EPSP)
Term
What is the hyperpolarization produced by an inhibitory neurotransmitter called?
Definition
Inhibitory Postsynaptic Potential (IPSP)
Term
What are the 2 types of summation of EPSP's?
Definition
1. Temporal summation-several EPSP's are deflivered at one synapse in a short period of time
2. Spatical Summation-EPSP's are delivered at several synapses relatively simultaneously.

**Both may be occuring
Term
Can EPSP's and IPSP's be delivered at the same time?
Definition
Yes
Term
What determines whether a cell reaches threshold or is inhibited?
Definition
the ratio of EPSP's to IPSP's
Term
3 Examples of catecholamine Neurotransmitters?
Definition
epinephrine, norepinephrine, and dopamine
Term
Do catecholamine neurotransmitters open the chemically regualted gates?
Definition
No thhey bind to a receptor in the post synapic cell that converts the ATP to cAMP which acts as a second messenger and opens the gates.
Term
Are catecholamine neurotransmitters destoryed after use?
Definition
No reabsorbed by the bouton and reused
Term
4 substances that have been id that act as neurotransmitters
Definition
1) Seratonin-amine-affects moods anf level of consciousness
2)GABA(Gamma Amino Butynic Acid)-inhibitory CNS neurotransmitter
3)Glycine-amino acid-acts at motor synapses in the spinal cord
4)Endorphins-tenkephalins-bind to or at CNS "opiate" receprots (pain receptors) -BLOCK PAIN
Term
meninges
Definition
Layers of CT surrounding the CNS
Term
What are the 5 major brain regions?
Definition
1. Telencephalon
2. diencephalon
3. Mesencephalon
4. Metencephalon
5. Myelencephalon
Term
What is the largest single discrete structure in the brain that constitutes about 80% of brain mass?
Definition
Cerebrum
Term
The cerebrum is divided by the longitudinal ------------- -----------into right and left ------------- ---------------------and they are connected by the ------------- -------------.
Definition
cerebral
fissure
cerebral
hemispheres
corpus
collosom
Term
What does the left hemisphere handle?
Definition
ananlytical and mathmatical ablilities, speech and language abilities
Term
What does the right hemisphere handle?
Definition
artistic and spacial abilities and allso intuitive reasoning and non-verbal communication
Term
Does one side of the brain usually dominate?
Definition
Yes
Term
What does the precentral gyrus do?
Definition
voluntary motor area
Term
What does the post-central gyrus do?
Definition
Somatic sencory area
Term
What does the Wernicks's area do?
Definition
Speech interp and formation(left side only)
Term
What does the broca's area do?
Definition
Motor speech area (Left side only)
Term
What does the frontal lobe do?
Definition
Handles personality and highter emotions.
Term
What does the parietal lobe do?
Definition
Handle spatial and visual relationships and memory aof spacial relationship somatic sensory interpretation(Wernicke's area)
Term
What does the temporal lobe do?
Definition
Handles memory of visual and auditory experience, speech processing and formation
Term
What connects the Broca's area and Wernicke's area?
Definition
A deep nerve tract= arcuate fascisulus.
Term
What does the occipital lobe do?
Definition
recieves and processes incoming info from the retinas they "flip the image", provide depth preception, facial recognition
Term
What is the 5th lobe? What does it do?
Definition
Insula-involved in regulating emotional states
Term
What are the 3 sets of fiber tracts handles the communication with in the brain?
Definition
1. Association- connect area with in the hemmisphere 2. Commissural-connect the 2 hemispheres via corpus callosum 3. projection-connect the cerebrum with the lower brain via thalamus
Term
What do the olfactory bulbs do?
Definition
Recieve and process incoming olfactory impulses to provide your sense of smell
Term
What 3 parts is the diencephalon divided into?
Definition
Epithalamus, Thalamus, and hypothalamus
Term
What secretes CSF into the ventricle?
Definition
Choroid Plexis(blood vesseles covered w/ ependyma) in the Epithalamus
Term
What connects the 2 superior colliculi of the mesencephalon?
Definition
posterior commissure in the epithalamus
Term
What projects posteriorly from the epithalalmus? what does it do?
Definition
Pineal body=epiphysis remnant of the original 3rd eye. responds to light produces melatonin
Term
What does the Thalamus function as?
Definition
relay center between the cerebrun and lower brain
Term
What is loc. at the Thalamus? What connects the 2 sides?
Definition
3rd ventricle the interthalamic adhesion connects the 2 sides
Term
What kind of memory is the thalamus involved in?
Definition
Short-term
Term
What does the hypothalamus regulate?
Definition
autonomic, endocrine, and emotional regulation
Term
What does most of the Hypothalamus consit of?
Definition
Mammillary bodies
Term
What are the eight centers of the Hypothalamus?
Definition
1. thermoregulatory center
2. Osmoregulatory center
3. Cardiovascular center
4. Feeding and Gastrointestinal center
5. sleep and wakefullness center
6. sexual center
7. emotional center
8. endocrine control center
Term
What do chemical imbalances in the emotional center cause? examples?
Definition
psychiatric disturbances
ex:chronic depression,anxiety, OCD, paranoia, schizophrenia, and psychosis
Term
what do Tricyclic antidepressants do? examples?
Definition
increase serotonin inhibition of mood centers BUT can have harsh side effects EX: elavil & triavil
Term
What do selective serotonin Reuptake inhibitors do? EX?
Definition
Used to treat chronic depression,OCD, no harsh side effects EX:Prozac, Paxil, Zoloft
Term
What do anit-anxiety meds do? EX?
Definition
enhance the inhibitory effects of GABA on the anxiety centers EX: Librium, Valium, Xanax **long term cause seizure activity
Term
What do anit-psychotics do? EX?
Definition
Block dopamine receprtors in the mood centers and produce an extreme calm non-excitiable state EX: thorazine, Haldol, Mellaril **long term tardive dyskinesia
Term
What do anit-manic agents do? EX?
Definition
help control manic episodes of Bipolar disorder EX: Lithium, Depakote
Term
What are the 2 pairs of rounded buldges of the roof of the midbrain in the mesencephalon? Each name?
Definition
Corpora Quadrigemina
Superior colliculi-control visual reflexes
inferior colliculi-control auditory reflexes
Term
What are the 2 important motor neclei deep in the midbrain (mesencephalon)?
Definition
1. Red nucleus-connects the cerebellum w/ the motor cerebrum
2. Substantia Nigra- dopaminergic nucleus involved w/inhibiting involuntary motor spasms. DEFICIECY=Parkinsons's
Term
What connects the 3rd and 4th ventricles?
Definition
cerebral Aqueduct
Term
Venturally the mesenchepalon consists of a pair of bludges called?
Definition
Cerebral Peduncles
Term
Superior Peduncles?
Definition
connect cerebellum w/ motor cerebrum via red nucleus
Term
Middle Peduncles?
Definition
conncet motor cerebrum w/ cerebellum via pons
Term
Inferior Peduncles?
Definition
carry sensory info from and motor info to body
Term
In the metencephalon what controls respiratory rate?
Definition
Pneumotaxic center
Term
What is the myelencephalon?
Definition
medulla oblongata
Term
What does the myelencephalon resemble?
Definition
spinal cord
Term
Pair of ventral triangular bluges on the medulla oblongata?
Definition
pyramids
Term
Pair of lateral bulges on the medulla oblongata?
Definition
olives
Term
3 centers of the medulla oblongata?
Definition
1. cardiac center
2. vasomotor center
3. respiratory rhythmicity center
Term
Is the metabolic rate of nervous tissue high or low?
Definition
high
Term
Does the metabolic rate of your brain change with activity or consciousness?
Definition
no
Term
What is constant blood flow that the brain recieves?
Definition
750mL/min
Term
What is the flow to the brain under?
Definition
autoregulation ie regulates its own supply
Term
The brain relies exclusively on what for energy?
Definition
glucose
Term
The CSF is higher in what ?
Definition
na, cl, mg, h
Term
the CSF is lower in what?
Definition
k, ca, glucose
Term
What is the major nerve trunk connecting the brain with the body?
Definition
Spinal cord
Term
The spinal cord starts and ends where?
Definition
Medula-L1
Term
What are the 2 prominet swellings of the spinal cord?
Definition
1.Cervical enlargement(c3-t2)
2.Lumbar enlargement(t9-t12)
Term
Where the cord tapers to an end what is it called?
Definition
conus medulla
Term
What is the thin thread that extends beyond the end of the spinal cord?
Definition
filum terminale
Term
What is the brush-like cluster of the last few pairs of spinal nerves called?
Definition
cauda equina
Term
What are the 3 subdivisions of the white matter of the cord?
Definition
1. dorsal funiculi-sensory only
2. lateral funiculi-mixed
3. ventral funiculi-mixed
Term
Spina Bifida
Definition
results from failure of vertebrae to fuse properly mid-dorsally. This allows sac of meninges and possibly nervous tissue to protrude thru the gap. most commonly in the lumbar region. CAUSES:locomotor difficulties,possible incoherence, possible paralysis. mild cases=surgery
serious=death
Term
What can help lower the risk of spina bifida?
Definition
prenatal folic acid supplements
Term
Anencephalia
Definition
No brain=lethal
Term
What developmental anomalie is liked to the prenatal exposure to various aromatic hydrocarbons?
Definition
Anencephalia and microcephaly
Term
Microcephaly
Definition
"pin head"=incomplete brain formation. severe retardation, often permantly bed ridden
Term
Hydrocephalus
Definition
Water on the brain=excessive production or inadquate drainage of CSF. CAuses cranial expasion and brain atrophy.= moderate to severe retardation without TX. peritoneal shut to relieve pressure.
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