Reflex Vs. Response

Question 1

What makes up reflexes

Answer 1

• Afferent N. (spinal cord segment)
• Efferent N and motor unit

Question 2

Responses require ________ awareness but do not require ________ input

Answer 2

Responses require Cortical awareness but do not require cerebral input

Question 3

T/F reflexes imply consciousness and imply perception

Answer 3

false reflexes does not imply consciousness or percerption

Question 4

what are the two components that make up a reflex arc

Answer 4

1. afferent: sensory
2. Efferent: motor

Question 5

what is a monosynaptic spinal reflex arc

Answer 5

it is an arc that consists of one afferent and one efferent nerve

Question 6

what is a polysynaptic spinal reflex arc

Answer 6

-one afferent and many efferent (some may be stimulatory or inhibitory)

Question 7

what are 2 unique characteristics associated with polysynaptic reflex arcs

Answer 7

1. will have interneuron associated
2. Also, the stimulus may travel up the white matter to the cerebral cortex
   
   1. this is for perception and memory
   2. this allows for a reflex to be perceived and can elicit a response to the reflex

Question 8

what are the target somatic organs

Answer 8

skeletal muscle

Question 9

what are the target autonomic organs

Answer 9

Smooth/cardiac muscle or glands

Question 10

What is a “response”

Answer 10

• a voluntary behavior that requires a cortical input
• perception of a stimulus (leads to) responsive movement made

Question 11

what the difference between the afferent pathway of reflexes and responses

Answer 11

the afferent pathway for responses is the same as reflexes except that the signal continues to the cortex of the brain

Question 12

what are reflexes

Answer 12

• reflexes are protective mechanisms
• These motions can occur without perception
  
  • the cortex is not necessary for reflexes

Question 13

what are the questions used by clinicians to determine the presence/location of a spinal cord lesion

Answer 13

1. is the reflex intact or absent
   
   1. If the reflex is intact is it normal, hyper/hypo-reflexive
2. us there an associated response also

Question 14

What is another name for the Panniculus reflex

Answer 14

cutaneous trunci reflex

Question 15

The Cutaneous Trunci reflex test the integrity of what

Answer 15

• afferent N
• spinal cord segments
• lateral thoracic nerve
• Cutaneous Trunci M

Question 16

where are the Afferent fibers contained for the Cutaneous Trunci Reflex

Answer 16

Afferent fibers are contained within the dorsal branches of spinal nerves (C8-L4)

Question 17

why must we bilaterally test the Cutaneous Trunci Reflex

Answer 17

there could be a unilateral lesion, so we must test bilaterally

Question 18

what are the afferent n. associated with Cutaneous Trunci Reflex

Answer 18

superficial pain receptors

Question 19

what spinal segments are associated with Cutaneous Trunci Reflex

Answer 19

From the site of pinch cranially to the cell body of the lateral thoracic nerve located C8-T1

Question 20

what Efferent n are associated with the Cutaneous Trunci Reflex

Answer 20

lateral thoracic n (cell body originates at C8-T1)

Question 21

what motor unit is associated with Cutaneous Trunci Reflex

Answer 21

cutaneous trunci mm.

Question 22

what is the reflex pathway associated with Cutaneous Trunci Reflex

Answer 22

• Afferent n
  
  • travels to the spinal cord segment at the level of “pinch” ascends cranially until C8-T1
• an interneuron activates lateral thoracic nn. bilaterally
• Cutaneous Trunci m contracts
  
  • visible skin twitch

Question 23

if the Cutaneous Trunci Reflex what are some of the causes

Answer 23

1. Damage to afferent nociceptive fiber between C8-L4 spinal cord segments
2. Damage to spinal cord
3. Damage to the lateral thoracic n
4. Damage to the cutaneous trunci m.

Question 24

where is the site of stimulation for a forelimb withdrawal reflex

Answer 24

pinch a forelimb digit

Question 25

for the Forelimb withdrawal reflex which afferent pathway is related to the palmar aspect

Answer 25

* median * ulnar

Question 26

for the Forelimb withdrawal reflex which afferent pathway is related to the dorsal aspect

Answer 26

Radial n.

Question 27

what spinal cord segment is responsible for the forelimb withdrawal reflex

Answer 27

spinal cord segment C6-T2

Question 28

what are the efferent nerves that are associated with the forelimb reflex

Answer 28

* Musculocutaneous n * Median and ulnar

Question 29

what motor units are associated with the Musculocutaneous n of the forelimb withdrawal reflex

Answer 29

* Biceps brachii * brachialis

Question 30

what motor units are associated with the Median and ulnar n of the forelimb withdrawal reflex

Answer 30

Flexors of the carpus and the digits

Question 31

what is the nerve pathway of the pelvic limb withdrawal reflex for plantar surface of pes stimulation (efferent)

Answer 31

stimulation is carried via tibial n to the sciatic n to lumbosacral intumescence (L4-S2)

Question 32

what are the afferent motor units associated with the pelvic limb withdrawal reflex with the femoral nerve

Answer 32

* Flexors of the hip * iliospoas * sartorius * rectus femoris

Question 33

what are the afferent motor units associated with the pelvic limb withdrawal reflex with the Sciatic nerve

Answer 33

* flexors of the stifle * Biceps femoris * semimembranosus * semitendinosus

Question 34

what are the afferent motor units associated with the pelvic limb withdrawal reflex with the common peroneal nerve

Answer 34

* (AKA fibular n) * Flexors of the tarsus * cranial tibial * peroneus * longus mm

Question 35

which nerve inhibits the extension of the stifle with the pelvic limb withdrawal reflex

Answer 35

Femoral n will inhibit tone to the remaining 3 heads of the quadriceps

Question 36

can different branches of the same nerve (femoral) be stimulated and inhibited at the same time

Answer 36

yes

Question 37

Can the same nerve that was used as an afferent n be used as an efferent nerve

Answer 37

* yes * tibial to sciatic * sciatic n to stimulate flexion of the stifle

Question 38

what is crossed extensor reflex

Answer 38

Extension of the limb opposite of the withdrawal stimulus

Question 39

when can the crossed extensor reflex be seen

Answer 39

only in the normal standing patients

Question 40

what is the purpose of the crossed extensor reflex

Answer 40

to keep us standing despite the need for withdrawal reflex

Question 41

when is a cross-extensor reflex seen in recumbent animals

Answer 41

with spinal cord damage cranial to the limb that shows the reflex I.E.: a lesion at L2 spinal cord segment. This animal will have intact crossed extensor reflex of the hind limb while in lateral recumbency

Question 42

what suppresses the crossed extensor reflex when we are laying down

Answer 42

proprioception would suppress this reflex as soon as we lay down

Question 43

what is a Perineal reflex

Answer 43

* when a light touch/pinch to the skin of the anus/perineum to activate touch pressure receptors/nociceptors * this will result in the tightening of the anal sphincter m.

Question 44

what is the afferent and efferent nerve of the perineal reflex

Answer 44

Pudendal nerve

Question 45

What spinal cord segment does the perineal reflex test

Answer 45

S1-S3 and the pudendal n.

Question 46

when is the perineal reflex absent

Answer 46

with damage to the spinal cord segment S1-S3, or along the pudendal n pathway

Question 47

what are the other names for the Myotatic reflex

Answer 47

* Muscle spindle reflex * tendon tap reflex * stretch reflex

Question 48

what is an example of a myotatic reflex and what does it protect

Answer 48

1. Patellar reflex 2. Prevents damage from overstretching a ligament

Question 49

what is the result in the muscles of the myotatic reflex

Answer 49

to increase tone to the muscle being stretched

Question 50

what are the two pathways a myotatic reflex can take place

Answer 50

1. Tonic stretch reflex 2. Phasic stretch reflex

Question 51

what is the Tonic stretch reflex of the myotatic reflex

Answer 51

Manipulate limbs to determine resistance to manual manipulation

Question 52

what is the phasic stretch reflex of the myotatic reflex

Answer 52

Use reflex hammer to strike tendon and rapidly stretch muscle

Question 53

what are the afferent nerves used in the myotatic reflex

Answer 53

Afferents from muscle spindle receptors sensing muscle/tendon stretch

Question 54

What is a Clonus reflex

Answer 54

* a cloned reflex * after the first reflex, the upper motor neuron should moderate the reflex (inhibit the reflex) * if the patient has UMN disease (a lesion cranial to the reflex arc) they will often present with hyper-reflexive and or clonus

Question 55

what are the parts of the normal pain response circuit

Answer 55

* nociceptive afferent fibers * spinal segment * afferent neuron to the brain * normal parietal lobe (for conscious cortical involvement)

Question 56

how hard should you pinch to test pain response

Answer 56

pinch increasingly harder until you see a behavioral response from the animal

Question 57

Do you test deep pain if superficial pain is intact

Answer 57

No because compressive lesions of the spinal cord result in predictable loss of nervous function

Question 58

what is the order of loss of nervous function from a compressive lesion from first to last

Answer 58

1. Proprioception is lost 1st 2. motor function is lost next 3. Pain is lost last 1. superficial pain is lost first 2. deep pain will be lost last

Question 59

Is it possible to have an absent withdrawal reflex along with a normal pain response

Answer 59

Yes: efferent peripheral motor neuron could have a lesion

Question 60

Complete spinal cord lesions result in muscle tone and reflexes which are:

Answer 60

Absent At the site of the lesion and will show increased tone and hyper-reflexive caudal to the lesion