Lecture 7

Question 1

What kind of structure does the spinal cord have

Answer 1

laminar

Question 2

What do the grey and white matter represent in the spinal cord

Answer 2

cell bodies, pathways (respectively)

Question 3

Directional term for top of head

Answer 3

rostral

Question 4

Directional term for tail

Answer 4

caudal

Question 5

What two things do each vertebra have

Answer 5

a body and a spinous process

Question 6

Peripheral information gets into the spinal cord through the _______

Answer 6

dorsal roots

Question 7

Efferent signals are sent to the spinal cord through the ________

Answer 7

ventral roots

Question 8

Starting from the skull, vertebrae are numbered from ____ to ____ and then end with the _____

Answer 8

C1-L5, end with the sacrum

Question 9

Spinal segments are numbered from ____ to ____, but this classification does not correspond exactly to the vertebrae classification.

Answer 9

C1-S5

Question 10

The spinal cord ends at what vertebra

Answer 10

L1, or top of L2

Question 11

A synapse consists of what three things

Answer 11

presynaptic membrane, synaptic cleft, postsynaptic membrane

Question 12

What means a decrease in the efficacy of the synapse and may occur as a result of events on the pre or postsynaptic membrane

Answer 12

inhibition

Question 13

An excitatory synapse leads to a _______ of the postsynaptic membrane (bringing it closer to threshold)

Answer 13

depolarization

Question 14

An inhibitory synapse leads to a _______ of the postsynaptic membrane

Answer 14

hyperpolarization

Question 15

When one neuron hyperpolarizes the cell body or dendrites of another cell body

Answer 15

postsynaptic inhibition

Question 16

What will hyperpolarize the entire postsynaptic membrane, essentially shutting down that cell for a period of time to all incoming stimuli

Answer 16

postsynaptic inhibition

Question 17

During postsynaptic inhibition, a postsynaptic inhibitory synapse hyperpolarizes the postsynaptic membrane and _______ its responsiveness to excitatory synapses

Answer 17

decreases

Question 18

What causes axons of alpha motor neurons to branch very close to make excitatory synapses on renshaw cells

Answer 18

recurrent inhibition

Question 19

Motor neurons always have what type of effect

Answer 19

excitatory

Question 20

What cell does the inhibition during recurrent inhibition

Answer 20

renshaw cells

Question 21

If a renshaw cell is inhibited and then excited what will happen

Answer 21

nothing at all

Question 22

Why is it beneficial for alpha motoneurons to excite renshaw cells that will inhibit the same alpha motoneurons and gamma motoneurons

Answer 22

this is a mechanism controlling the amount of force produced during movement

Question 23

What do renshaw cells help stabilize

Answer 23

the firing rate of motor neurons

Question 24

What is it called when Ia interneurons receive excitatory inputs from Ia afferents and make inhibitory synapses on motoneurons innervating the antagonist muscle

Answer 24

reciprocal inhibition

Question 25

Ia interneurons are inhibited by what

Answer 25

renshaw cells and descending inputs

Question 26

What must happen to the renshaw cell before it can do inhibition

Answer 26

it must be excited

Question 27

Ia interneurons can be inhibited by renshaw cells to stop what

Answer 27

reciprocal inhibition

Question 28

What is occurring when a neuron contacts the axon terminal rather than the cell body of another neuron

Answer 28

presynaptic inhibition

Question 29

Presynaptic inhibition will reduce the amount of ________ released by the second neuron onto the third cell

Answer 29

neurotransmitter

Question 30

Presynaptic inhibition is more _____ than postsynaptic inhibition

Answer 30

specific or selective

Question 31

An excitatory synapse acting on the presynaptic membrane, inducing its subthreshold depolarization, thus decreasing the amount of mediator released in response to a single presynaptic action potential

Answer 31

presynaptic inhibition