15.1

Question 1

polarity of neuron

Answer 1

1 dendrite = bipolar

1+ dendrite = multipolar

Question 2

if a toxin prevent voltage-gated sodium channels from closing, what will occur?

Answer 2

• 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

Question 3

what is it called when APs propogate along a myelinated axon

Answer 3

saltatory conduction

Question 4

if cell were completely permeable to K, the resting potential would be

Answer 4

-90 mV

not many leak channels for sodium, otherwise the cell would be more positive. complete permeability = +35 mV

Question 5

absolute and relative refractory periods

Answer 5

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)

Question 6

acetylcholine

Answer 6

depolarizes the postsynaptic membrane = EXCITATORY

although it’s the receptor that determines the effect

Question 7

intensity of signal

Answer 7

= frequency of APs

Question 8

motor neurons

Answer 8

act on effectors (efferent neurons)

Question 9

basal nuclei

Answer 9

“thai basil is full of movement”

• work with cerebellum to process and coodinate movement
• inhibitory (prevents excess), while cerebellum is excitatory

Question 10

Broca’s area

Answer 10

“can you say Bro..?” - speech production

Question 11

somatic PNS

Answer 11

• 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

Question 12

efferents of somatic and PS systems…

Answer 12

consist of two neurons: preganglionic and postganglionic

Question 13

preganglionic neuron

Answer 13

cell body in brainstem or spinal cord, sends and axon to autonomic ganglion, located outside the spinal column

synapses with a post-ganglionic neuron

Question 14

post-ganglionic neuron

Answer 14

send an axon to effector

Question 15

PNS neurotransmitter

Answer 15

all autonomic preganglionic neurons release ACh

All parasympathetic postganglionic neurons release ACh

all sympathetic postganglionic neurons release norepinephrine

Question 16

pitch

Answer 16

affects different areas of basilar membrane

Question 17

basilar membrane

Answer 17

thick narrow and sturdy near the oval window

wider, thinner, and floppy at apex (low frequencies)

Question 18

loudness and AP

Answer 18

increase frequency of AP

Question 19

rods and cones

Answer 19

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

Question 20

bipolar cells “on center”

Answer 20

“on center” inhibited by glutamate

“off center” - bipolar cells stimulated by glutamate -> firing of ganglion cell starts/increased

Question 21

thyroid hormone and protein synthesis

Answer 21

thyroid hormone regulates transcription in the nucleus