Lecture 7

Question 1

the spinal cord has a ______ structure

Answer 1

laminar

Question 2

geographical terms that will be helpful in descriptions

Answer 2

posterior 
anterior 
lateral
medial
dorsal
ventral

Question 3

each vertebrae has a ______ and a _____.

Answer 3

body and a spinous process

Question 4

Peripheral information gets into the spinal cord through ________.

Answer 4

dorsal roots.

Question 5

Efferent signals are sent from the spinal through the _______.

Answer 5

ventral roots

Question 6

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

Answer 6

C1 to L5

Question 7

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

Answer 7

C5 to L1

Question 8

A synapse consists of:

Answer 8

a presynaptic membrane, a synaptic cleft, and a postysynaptic membrane

Question 9

Inhibition means _____ in the efficacy of the synapse and may occur as a result of events on the presynaptic or postsynaptic membrane

Answer 9

decrease

Question 10

An excitatory synapse leads to a:

Answer 10

depolarization on the postsynaptic membrane

Question 11

An inhibitory synapse leads to a:

Answer 11

hyper polarization on the postsynaptic membrane

Question 12

Postsynaptic Inhibition

Answer 12

when one neuron hyper polarized the cell body (or dendrites) of another cell body.

Question 13

Postsynaptic Inhibition will hyperpolarize the entire postsynaptic membrane, essentially __________

Answer 13

shutting down that cell for a period of time to all incoming stimuli.

Question 14

Postsynaptic inhibition is a more _____ type of inhibition

Answer 14

general

Question 15

A postsynaptic inhibitory synapse hyper polarizes the postsynaptic membrane and _________.

Answer 15

decreases its responsiveness to excitatory synapses.

Question 16

Axons of alpha-motorneurons branch very close to the cell body and make______.

Answer 16

excitatory synapses on Renshaw cells

Question 17

Renshaw cells make _________ on alpha motorneurons

Answer 17

renshaw cells make inhibitory synapses on alpha motoneurons of the same pool as well as on y-motoneurons, sending their axons to spindles in the SAME muscle.

Question 18

Recurrent Inhibition

Answer 18

Basically, alpha motoneurons excite the cells (Renshaw cells) that inhibit the same alpha motoneurons

Question 19

Why is recurrent inhibition beneficial?

Answer 19

Henshaw cells help stabilize the firing rate of motor neurons.

Question 20

In Reciprocal Inhibition, Ia interneurons receive ______ inputs from Ia afferents & make _______ synapses on motoneurons innervating the antagonist muscle

Answer 20

excitatory; inhibitory

Question 21

In Reciprocal Inhibition, The INs are inhibited by Renshaw cells and also receive _________ inputs.

Answer 21

descending

Question 22

In Recurrent Inhibition, alpha motoneurons send axon branches to small ________ interneurons (Renshaw cells) in the ventral horns of the spinal cord

Answer 22

inhibitory

Question 23

Renshaw cells ______ all motoneurons of the same pool.

Answer 23

inhibit

Question 24

In Reciprocal Inhibition, __________ are activated by primary spindle afferent fingers.

Answer 24

small interneurons (Ia interneurons)

Question 25

In Reciprocal Inhibition, the Ia interneurons _________ motoneurons of the antagonist muscle

Answer 25

inhibit.