8. Localization and Differentiation of Neurologic Diseases

Question 1

What area of the brain maintains mental alertness?

Answer 1

The Ascending Reticular Activating System (ARAS) of the brainstem. (repetitively signals the forebrain to maintain consciousness)

Question 2

What is the function of the spinocerebellar tracts?

Answer 2

Convey proprioceptive information from the spinal cord to the cerebellum

Question 3

What does an inability to resist a tail pull at rest indicate?

Answer 3

Suggestive of a lower motor neuron (spinal cord grey matter, nerve roots, or peripheral nerves) of L3-S2 spinal cord segments on the side being tested

Question 4

Unilateral lesions in the medulla oblongata or spinal cord cause severe proprioceptive and postural deficits in the _________ limbs

Answer 4

Ipsilateral

Question 5

Unilateral lesions rostral to the medulla oblongata produce mild to moderate proprioceptive and postural deficits in the _________ limbs

Answer 5

Contralateral

Question 6

Animals that are in lateral recumbency and unable to lift the head from the ground may have lesions….

Answer 6

Peripheral or brainstem vestibular centers or in the cervical spinal cord cranial to C4 when lesion side is up

Question 7

A laterally recumbent animal that can lift head but not rotate thorax may have a lesion…

Answer 7

C7 to T2

Question 8

When rising, animals with lesions of the thoracolumbar and lumbosacral spinal cord (T3 to S3 spinal cord segments) can…

Answer 8

Usually, lift the head and neck, arise on the thoracic limbs, and assume a dog-sitting position

Question 9

Define Upper Motor Neuron

Answer 9

A nerve cell contained completely within the CNS, with cell bodies in the brain and axons that terminate at synapses within the brain or spinal cord.

Question 10

Define Lower Motor Neuron

Answer 10

The cell bodies are in the nuclei of of cranial nerves in the brainstem or in the ventral horn grey matter of the spinal cord. The axons exit the CNS and terminate at neuromuscular junctions

Question 11

Diseases affecting lower motor neurons result in… (5)

Answer 11

1. Decreased spinal reflexes
2. Ataxia
3. Moderate to severe weakness
4. Decreased muscle tone (flaccidity)
5. Rapid, pronounced atrophy of the denervated muscles.

Question 12

Diseases affecting upper motor neurons result in…(3)

Answer 12

1. Normal to increased spinal reflexes
2. Variable severity of weakness
3. Variably increased muscle tone (spasticity)

Question 13

Lesions in the spinal cord cranial to the level of the reflex arc and lesions of the brain result in ______ myotatic reflexes

Answer 13

Normal to Increased

Question 14

Lesions in either the afferent or the efferent components of the reflex arc result in _____ myotatic reflexes

Answer 14

Decreased to Absent

Question 15

The triceps reflex measures the integrity of the ____

Answer 15

Radial nerve and C7, C8, T1 spinal segments

Question 16

The Biceps reflex measures the function of the ____ (Slight difference between horses and cattle)

Answer 16

Musculocutaneous nerve and spinal cord segments C6 to C8 in ruminants and C7 and C8 in horses

Question 17

The thoracic limb flexor reflex tests the integrity of the _______

Answer 17

Axillary, median, and musculocutaneous nerves and spinal cord segments C5 through T2, as well as the flexor muscles of the limb

Question 18

The pelvic limb flexor reflex is mediated by ______

Answer 18

Sciatic, peroneal, and tibial nerves; the pelvic limb flexor muscles; and spinal cord segments L6 to S2

Question 19

The perineal reflex is mediated by the _____

Answer 19

Pudendal nerve and spinal cord segments S1 to S5

Question 20

The Cutaneous trunci reflex evaluates ___

Answer 20

C8 to T1 in ruminants and C8 to T2 in horses and the lateral thoracic nerve

Question 21

The cervical reflex evaluates ____

Answer 21

the integrity of the dorsal funiculi of cervical spinal cord segments and the facial nerve in the medulla oblongata.

Question 22

Reduced or absent laryngeal adductor reflexes are found in animals that have lesions of ____

Answer 22

The cervical spinal cord, caudal brainstem, vagus nerve, and left recurrent laryngeal nerve

Question 23

The tone of the thoracic limbs is controlled through (Spinal segments and 6 nerves)

Answer 23

spinal cord segments C6 to T2 and the radial, musculocutaneous, median, ulnar, axillary, and long thoracic nerves

Question 24

The motor tone of the pelvic limbs is controlled through (spinal segments and 4 nerves)

Answer 24

L3 to S2 and the femoral, cranial and caudal gluteal and sciatic nerves

Question 25

Loss of oculomotor nerve function results in

Answer 25

Ventrolateral strabismus, loss of PLR, ptosis

Question 26

Trochlear nerve dysfunction results in

Answer 26

Dorsomedial strabismus

Question 27

Loss of abducent nerve function results

Answer 27

Medial strabismus and inability to retract the globe

Question 28

Functions of the Trigeminal Nerve

Answer 28

Sensory to the face and motor to the muscles of mastication

Question 30

Equine Vertebral Formula

Answer 30

C₇T₁₈L_5-6Cd_15-21

Question 31

Ox Vertebral Formula

Answer 31

C₇T₁₃L₆S₅Cd_18-21

Question 32

What can cause Horners Syndrome?

Answer 32

Lesion along preganglionic or postganglionic sympathetic nerve fibers or in spinal segments T1-3 or rarely in the upper motor neuron component of the sympathetic pathway in the cervical spinal cord or brainstem