15.1 Flashcards
polarity of neuron
1 dendrite = bipolar
1+ dendrite = multipolar
if a toxin prevent voltage-gated sodium channels from closing, what will occur?
- Voltage-gated K channels will open but won’t close because the membrane will not be repolarized
- The membrane will not fully repolarize, Na will flow into the cell
what is it called when APs propogate along a myelinated axon
saltatory conduction
if cell were completely permeable to K, the resting potential would be
-90 mV
not many leak channels for sodium, otherwise the cell would be more positive. complete permeability = +35 mV
absolute and relative refractory periods
neuron will NOT fire during absolute RP, no matter how strongly induced from membrane depolarization. V-gated Na channel are INACTIVATED, and they are not CLOSED until the membrane potential reaches the resting potential
Relative RP - neuron can transmit an AP, but requires a greater depolarization because the membrane is HYPERPOLARIZED (more negative than normal)
acetylcholine
depolarizes the postsynaptic membrane = EXCITATORY
although it’s the receptor that determines the effect
intensity of signal
= frequency of APs
motor neurons
act on effectors (efferent neurons)
basal nuclei
“thai basil is full of movement”
- work with cerebellum to process and coodinate movement
- inhibitory (prevents excess), while cerebellum is excitatory
Broca’s area
“can you say Bro..?” - speech production
somatic PNS
- innervates skeletal muscle cells
- ACh
- cell brains live in brain or ventral portion of spinal cord
- Somas located just outside the CNS in dorsal root ganglion
efferents of somatic and PS systems…
consist of two neurons: preganglionic and postganglionic
preganglionic neuron
cell body in brainstem or spinal cord, sends and axon to autonomic ganglion, located outside the spinal column
synapses with a post-ganglionic neuron
post-ganglionic neuron
send an axon to effector
PNS neurotransmitter
all autonomic preganglionic neurons release ACh
All parasympathetic postganglionic neurons release ACh
all sympathetic postganglionic neurons release norepinephrine
pitch
affects different areas of basilar membrane
basilar membrane
thick narrow and sturdy near the oval window
wider, thinner, and floppy at apex (low frequencies)
loudness and AP
increase frequency of AP
rods and cones
change tertiary shape.
contains opsin, bound to 1 molecule of retinal (Vitamin A)
night: several trans and 1 cis; sodium channel is open, cone depolarized; glutamate is released
photon: all-trains, closes sodium channel, hyperpolarizes; stop release of glutamate
bipolar cells “on center”
“on center” inhibited by glutamate
“off center” - bipolar cells stimulated by glutamate -> firing of ganglion cell starts/increased
thyroid hormone and protein synthesis
thyroid hormone regulates transcription in the nucleus
