test 1: lecture 8

Question 1

interfusal fibers are stimulates by ___

Answer 1

gamma neuron

Question 2

extrafusal fibers are innervated by ___

Answer 2

alpha motor fiber

Question 3

spinal nerve and their relationship to vertebral bodies

Answer 3

there are 8 cervical spinal nerves

C1-7 come off before its named vertebrae

C8 after Cervical Vet 7

spinal nerve T→ sacral comes off after the named vertebrae

Question 4

division of spinal cord

Answer 4

C1-5

C6-T2 (front leg)

T3-L3

L4-Caudal5 +cauda equina (back leg)

Question 5

lumbar enlargment

Answer 5

Question 6

femoral nerve is made of what spinal nerve?

Answer 6

L4,5,6

Question 7

obturator nerve is made of what spinal nerve?

Answer 7

(L4) 5, 6

Question 8

cranial gluteal is made of what spinal nerves

Answer 8

L6,7, S1

Question 9

caudal gluteal is made of what spinal nerves

Answer 9

L7, (S1 and S2)

Question 10

sciatic nerve is made of what spinal nerves?

Answer 10

L6, 7, S1 and (S2)

Question 11

what spinal nerves innervate the front limbs?

Answer 11

radial

ulnar

musculocutaneous

Question 12

what nerve innervates the pelvic limbs?

Answer 12

femoral

sciatic which branch into the

• tibial
• peroneal

Question 13

myotatic reflexes

Answer 13

stretch reflexes

Question 14

3 types of myotatic reflexes for the front limb

Answer 14

Stretch reflex

• Extensor carpi radialis reflex
• Triceps reflex
• Biceps reflex

Question 15

3 types of myotatic reflexes for the hind limb

Answer 15

stretch reflex

• Patellar reflex
• Cranial tibial reflex
• Gastrocnemius reflex

Question 16

alpha motor neurons go to ___ and are under ___ control

Answer 16

skeletal muscle fibers

voluntary motor

Question 17

gamma motor neurons go to ___ and help regulate ___ reflex. Gamma will also create the ___ for alpha motor neurons.

Answer 17

muscle spindles (intrafusal fibers)

stretch

baseline activity

Question 18

___ neuron help with proprioception and tone and position

Answer 18

gamma motor

Question 19

withdrawal reflex on back leg

Answer 19

pinch toe

sensory through dorsal root

synapse in dorsal horn on interneuron

interneuron will synapse on motor to send flexor contraction and extensor inhibition on same side

another interneuron will synapse and send contralateral extensor inhibition by UMN to other limb (body is laying down does not need to extend not pinched leg)

Question 20

perineal reflex

Answer 20

anal sphincter

Question 21

babinski

Answer 21

flexion (normal)

extension (bad)

Question 22

crossed extensor reflex

Answer 22

pathologic- something is wrong- lesion somewhere

pet laying down pinch R toe

R leg flexes, L leg extends

(in normal, when laying down, there should not be movement in L leg)

Question 23

crossed extensor reflex is a ____ motor neuron sign

Answer 23

upper

(there is a lesion somewhere in the spinal cord that is preventing a signal from telling the opposite leg to NOT move when laying down)

contralateral extension NOT inhibited by YMN

Question 24

cutting lower motor neuron results in

Answer 24

small reflex

decreased tone

Question 25

cutting UMN will cause

Answer 25

**big reflex** (hyper-reflexive) spastic tone (increased)

Question 26

upper or lower motor nerve damage results in increased tone?

Answer 26

upper increased tone and big relfex

Question 27

upper or lower motor neuron defect results in flaccid muscles?

Answer 27

lower flaccid and weak reflex

Question 28

what toxin results in stiffness and big reflexes

Answer 28

tetanus

Question 29

what results in weakness/paresis and paralysis

Answer 29

damage to motor neurons

Question 30

lower motor neuron disorders

Answer 30

- Decreased segmental reflexes - Paresis (flaccid) - Short strided gait - +/- cranial nerve deficits

Question 31

monosynaptic spinal reflex

Answer 31

damage to UMN (tract in spinal cord) **big reflex** **spastic paresis** +/- CN deficits

Question 32

upper motor neuron disorders

Answer 32

**big reflex** **spastic paresis** +/- CN deficits

Question 33

\_\_\_ motor neuron disorder causes short strided gait

Answer 33

lower motor neuron disorder