Reflexes and Responses

Question 1

True/False. A conscious integration occurs at the level of the spinal cord and will give us a reflex.

Answer 1

False. Unconscious

Question 2

A reaction/ response occurring in the cortex of the brain is what kind of integration?

Answer 2

Conscious

Question 3

What kind of a reflex and response to a stimulus is the withdrawal of a limb?

Answer 3

Unconscious response, somatic reflex

Question 4

The bladder reflex is what kinda of reflex?

Answer 4

Visceral reflex

Question 5

Which of the following is false regarding the reflex arc?

a. If any component in the reflex circuit is “broken,” reflex will not happen
b. Can have both somatic and visceral reflexes
c. The reflex requires the cerebral cortex for conscious response
d. All the above are true

Answer 5

c. The reflex requires the cerebral cortex for conscious response
- reflex does NOT require cerebral cortex = unconscious

Question 6

What sections of the spinal cord are examined for a gait analysis?

Answer 6

Cervicothoracic region C6-T2

Lumbosacral region L4-S2

Question 7

How will an animal respond if the myotactic/stretch arc is intact?

Answer 7

They will “push back” or kick their legs out

Question 8

How will an animal respond to a cutaneous stimulation, light pinch, in the limbs if the arc is intact?

Answer 8

Withdrawal the limb (withdrawal/ flexor reflex)

Question 9

What reflexes can you use the Stretch (Myotactic) Reflex to test?

Answer 9

Patellar reflex
Triceps reflex
Biceps reflex

Question 10

What is clonus?

Answer 10

When the muscle relaxes after a reflex is over and then joint/ tendon stretches again “cloning” the reflex

Question 11

Upper brain centers present the clonus via inhibition of ____ activity.

Answer 11

Lower Motor Neuron

Question 12

What is usually associated with an UMN disorder?

Answer 12

Hyper-reflexive state and/or clonus

Question 13

What can we use cutaneous stimulation to test?

Answer 13

Autonomous zones of various nerves
Panniculus (cutaneous trunci) reflex
Recumbent withdrawal/crossed extensor reflex
Perineal reflex

Question 14

What is the Panniculus Reflex useful for?

Answer 14

Locating C8 and T1 spinal cord lesion and their contribution sot the lateral thoracic nerve

Question 15

When testing the sensory stimulus of the panniculus reflex where do you begin and how far cranially do you progress when compressing the skin?

Answer 15

Begin at L4 and progress cranially to T2

Question 16

Is the withdrawal (Flexor) Reflex monosynaptic or polysynaptic?

Answer 16

Polysynaptic

Question 17

What segments of the spinal cord are you testing with the perineal reflex?

Answer 17

S1-S3 and the pudental nerve

Question 18

What is the normal response of the perineal reflex when you pinch the skin near the anus/perineal region?

Answer 18

Tightening of the external anal sphincter muscle

Question 19

What are the afferent and efferent nerves of the pupillary light reflex?

Answer 19

Afferent: Optic (CN II)
Efferent: Occulomotor (CN III)

Question 20

What are the afferent and efferent nerves involved in the corneal reflex?

Answer 20

Afferent: Opthalmic branch of CN V
Efferent: Facial CN VII (blink); Abducens CN VI (retraction of the globe and passive movement of the 3rd eyelid)

Question 21

What are the afferent and efferent nerves involved in the palpebral reflex?

Answer 21

Afferent: maxillary branch of CN V (lateral canthus) and opthalmic branch of CN V (medial canthus)
Efferent: Facial CN VII

Question 22

Which two nerves are the main contributors to the micturition reflex?

Answer 22

Pudendal nerve and Pelvic nerve

Question 23

True/False. The Pudendal nerve is the visceral afferent component that provides stretch receptors in the bladder wall.

Answer 23

False. Pelvic nerve

Question 24

Which nerve stimulates somatic efferent neuron cells bodies in the sacral spinal cord resulting in the contraction of the external urethral sphincter?

Answer 24

Pudendal nerve

Question 25

Activity of urine voiding stimulates contraction of ____ muscle and inhibits the contraction of _____.

Answer 25

Detrussor muscle | Internal urethral sphincter

Question 26

What are the nerves that are involved in the micturition reflex?

Answer 26

Hypogastric nerve Pelvic nerve Pudendal nerve

Question 27

What clinical signs would one see if there was an UMN lesion in the micturition reflex?

Answer 27

Hyperreflexive | Taut bladder

Question 28

What are the afferent and efferent nerves involved in the menace response?

Answer 28

Afferent: Optic nerve CN II Efferent: Facial nerve CN VII

Question 29

Lower motor neurons are ____ neurons whose cell bodies are located in the spinal cord and specific brain nuclei

Answer 29

Somatic efferent neurons

Question 30

True/False. UMN are both unconscious and conscious regulation

Answer 30

False. LMN

Question 31

If we have an "inappropriate" reflex (hyper/hyporeflex), does this indicate an UMN lesion or LMN?

Answer 31

UMN

Question 32

What is the name of the pathway that regulates fine-tuned skilled movements?

Answer 32

Pyramidal pathways

Question 33

What is the extrapyramidal pathways?

Answer 33

UMN synapse onto interneurons and then onto LMN

Question 34

What is the role of the extrapyramidal pathways?

Answer 34

Maintain muscle tone and initiate whole limb movements

Question 35

Where do LMN axons directly synapse onto?

Answer 35

Skeletal muscle in the head and body

Question 36

True/False. The spinal cord reflex in isolation is a reflexive and unregulated movement.

Answer 36

True

Question 37

What is somatotopy?

Answer 37

Point-for-point correspondence of a specific body part to a specific region of the CNS

Question 38

Which somatotopy motor pathway is going to be associated with posture and balance and mainly extensors?

Answer 38

Ventromedial motor systems

Question 39

What is the dorolateral motor system/ column mainly associated with?

Answer 39

Fine/ precise movements Distal muscles Primarily flexors

Question 40

What system is damaged if the animal produces decreased or absent voluntary movements of the whole limb (mostly extensors) caudal to the site of damage?

Answer 40

Ventromedial motor system

Question 41

True/False. We will observe LMN signs at the site of the lesion/injury.

Answer 41

True

Question 42

The GSE cannot stimulate the target tissue and we have no reflexive contraction of the skeletal muscle. Is this a UMN sign or a LMN sign?

Answer 42

LMN sign

Question 43

If an animal has UMN lesion at C6-T2 will there be a reflex if we were to pinch the pelvic limb?

Answer 43

Yes! However, there will be no response or reflex if we are to pinch the thoracic limb

Question 44

What are the lower motor neuron signs exhibited at the site of the lesion/injury?

Answer 44

1. Paresis to paralysis 2. Decreased to absent muscle tone 3. Decreased to absent spinal reflexes 4. Rapid onset muscle atrophy