Ch. 7 Nervous System Test Flashcards
Def of -glia
glue
Star shaped cell, blood brain barrier, protects from harmful substances
astrocyte
Spider shaped cell, phagocyte (cell that eats dead brain cells)
microglial cell
lines brain & spinal cord, circulates CSF
ependymal cell
produces a fatty insulating material (myelin sheath), CNS
oligodendrocytes
produces a fatty insulating material (myelin sheath) but in the PNS
schwann cells
Action potential
rapid change in membrane potential, goes from -70 mV to +30 mV then back to -70 mV
Depolarization
charge becomes more +, Na+ moves into the cell
Element that makes charge more +
Na
Element that makes charge more - or neutral
Ka
What charge is the peak
+30
What charge is the threshold
-55
What charge is rest
-70
Absolute refractory period
can’t be disturbed, goes through entire cycle then can re-fire
positive feedback loop
depolarization –> Na+ gates open –> Na+ moves in
repeat
2 events that stop + feedback loop
1) Na+ channels close
2) K channels open
Repolarization
potassium is moving out of cell, returns to rest (-70 mV), once K leaves the more -
HYPERpolarization
past being polarized (most negative)
Def of neuro
nerve
Ion channels are
selective
Active
open/close
Passive
always open, AKA leakage channel
Passive channels maintain..
resting membrane potential
Chemically-gated channels
synaptic potential, afferent, taking stimuli in
Voltage-gated channels
action potential, efferent
Ion channels are needed in..
nerves since ions aren’t soluble in lipid bi-layer
Neurons are..
selectively permeable
Permeability can change rapidly due to..
number of gates opened
More channels, the permeability..
increases
K+ moves _____ concentration gradient, __ –> __, in order to reach _______, => outside becomes more _______
down, 6 & 1, equilibrium, positive
Resting neurons very permeable to ____ and slightly to ____
K+, Na+
Electrochemical gradient is based on _________, ____, and _______, ____ goes to _______ side
concentration gradient, 6:1, electrical attraction, Na+, negative
Na-K pump uses __________, (goes against ________ to maintain ______, ____ ratio
ATP/form of active transport, concentration gradient, -70 mV, 3:2
__ ____ out, __ ____ in, to maintain ______, AKA the ________
3 Na+, 2 K+ in, -70 mV, resting membrane potential
