Term
| what are the convoluted sticky out parts called in the brain? |
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Definition
gyrus
the grooves between gyri are called sulcus there is a prominent sulcus called the Lateral sulcus. this is also known as Sylvian fissure |
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Term
| the human brain is split into 4 main parts: brain stem, cerebellum.... name the other two |
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Definition
diencephalon and cerebrum
the brain stem is contionous with spinal cord and is associated with respiratory and cardiovascular control, swallowing and vomiting |
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Term
| what is located behind the brain stem and coordinates movement, balance, posture and maintains muscle tone? |
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Definition
| cerebellum - this part is affected by mad cow disease aka creuzt-feldt jakob disease. |
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Term
| i am continous with the spinal cord and am associated with respiratory and cardiovascular control, swallowing and vomiting. which part of the brain am i? |
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Definition
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Term
| principally the thalamus and hypothalamus, the diencephalon is located above the brain stem. what is it associated with? |
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Definition
| pain, touch, pressure, hot/cold sensations, soun, taste, smell, thirst, sleep patterns. |
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Term
| the cerebrum is very well developed in humans and has sensory, motor and association areas (seat of intelligence, memory and emotions), visual cortex. which part of the brain does the cerebrum surround? |
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Definition
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Term
the cerebrum consists of grey matter and white matter. grey matter is aka cortex and contains nerounal cell bodies and dendrites.
the white matter contains what? |
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Definition
myelinated axons.
the cortex is highly convoluted with sulci and gyri |
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Term
| the cerebrum is divided into two hemispheres connected by what? |
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Definition
corpus callosum.
each hemisphere is divided into 4 lobes: frontal, parietal,occipital and temporal. |
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Term
| the cerebral cortex is associated with somatosensory, motor and association cortex. which parts of the cortex are linked to somatosensory and motor areas? |
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Definition
somatosensory = anterior parietal
motor areas = posterior frontal |
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Term
| which part of the brain is affected in parkinson's disease? |
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Definition
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Term
true or false?
dendrites and neuronal body in grey matter. myelinated axons in white matter |
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Definition
this is true
oligodendrocytes myelinate in CNS
schwaan cells myelinate in PNS |
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Term
| neurons receive information at d............. (upto 100,000 synaptic inputs/neuron) and intergrate in cell b....... |
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Definition
dendrites
body
the information is transmitted along the axon in form of a electrochemical signal or nerve impulse (action potential)
action potentials are due to the flow of ions (Na+, K+) through specific protein channels in the membrane. the lipid bilayer is impermeable to these charged ions |
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Term
| in relation to transport of ions across cell membranes, some ion channels are always o..... whereas others are regulated or g.......... |
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Definition
open
gated
Both types are important for the physiology of nerve cells. gated ion channels are closed unless activated. these channels are specific for certain ions eg Na+, K+ and Cl- |
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Term
| gated ion channels can be mechanically, ligand or voltage gated. what do each of these involve? |
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Definition
voltage gated - involved in generation and propagation of nerve impulses
ligand gated - involved in neurotransmission at the synapse
mechanically gated - involved in perception of touch |
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Term
| a ligand gated ion channel opens in response to binding of a messenger or ligand eg hormone or neurotransmitter. what forces act to move ions through membrane channels? |
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Definition
chemical driving force - due to diffusion from a region of high to low concentration
electrical driving force - interior of cel is negatively charged thus positive cations get retained and negative anions get repelled |
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Term
| is the concentration of Na+ higher intracellular or extracellular? what about K+? |
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Definition
Na+ - higher outside 150mM
lower inside 15mM
K+ - higher inside 150mM
lower outside 5mM |
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Term
| the e.................. driving force is a combination of the chemical and electrical forces acting on any particular ion. it gives the nett force that acts to drive an ion into or o...... of the cell, through an open m............ channel |
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Definition
electrochemical
out
membrane
the inside of the axon has a resting membrane potential of -70mV. these studies were initially carried out with giant squid. |
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Term
| due to leak channels that are always open, some Na+ diffuses in and some K+ diffuese out. which one is more leaky and what is the ratio of K+ to Na+ diffusion? |
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Definition
K+ channels are more leaky so more K+ leaks out than Na+ at the ratio of 25:1
the sodium-potassium pump works to counteract this. it is active and uses ATP to pump 3Na+ out for every 2 K+ pumped into the cell. |
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Term
| the resting membrane potential is the difference in voltage across the PM when the cell is at rest. what two things does this resting membrane potential depend on? |
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Definition
concentration gradients for multiple ions across the membrane
the relative permeability of the membrane to those ions
the most important ions are Na+ and K+ |
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Term
| what are the forces acting on Na+ at resting memrane potential? (Vm) |
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Definition
electrical and chemical.
chemical = inside cell 15mM but out side 150mM thus chemical force drives Na+ into cell.
Electrical = inside cell is negatively charged and Na+ is a cation thus it attracts the positive cation.
as both act in the same direction Na+ will enter the cell |
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Term
| what are the forces acting on K+ at resting Vm? |
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Definition
chemical forces drive K+ out of the cell as the concentration is higher intracellular (150mM) than extracellular (5mM)
electrical forces drive K+ into the negatively charged cell.
as these forces act in opposite directions the net movement depends on which force is greater. |
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Term
| the equilibrium potential (E) is the membrane potential required to exactly counteract the chemical forces acting to move one particular ion across the membrane. which equation can be used to calculate the equilibrium potential? |
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Definition
the Nermst equation
E = 61/z log Cº/Ci
E = equilibrium potential (mV)
z = charge (valence) of the ion
Cº = outside conc. of the ion
Ci = inside conc. of the ion |
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Term
the equlibrum potential for Na+ is +60mV. this is g........ than resting Vm so sodium ions will try and e....... the cell
here both chemical and electrical forces act in the same direction |
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Definition
greater
enter
the equlibrium potential for K+ is -94mV (less than resting Vm) so K+ ions will try to move out of the cell.
chemical and electrical forces act in opposite directions but chemical force is greater
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