EVMM CNS and Cranial Nerves

Question 1

3 primary goals of the autonomic nervous system

Answer 1

1. Control involuntary movement
2. Maintain homeostasis
3. React to stress

Question 2

Size and myelination of alpha motor neurons, why this is important

Answer 2

Large, myelinated

Question 3

Location and stimulus of muscle spindle cells, of golgi tendon organs and joint receptors

Answer 3

MSC – muscle belly, monitor stretch
GTO – musculotendinous junction, monitor contraction
Joint receptors – joint angles

Question 4

4 things nerve cells need to thrive

Answer 4

Oxygen, glucose, neurotrophic factors, FOF

Question 5

Effect of a restriction on the frequency of firing of mechanoreceptors in that area and the effect on the cortex

Answer 5

Nociceptors sensitive to chemical changes and are continuously firing. They are inhibited by Ia fibers from mechanoreceptors.

Question 6

Name, e.g. olfactory, function and diagnostic test of each cranial nerve (no test for CN IV)

Answer 6

1. 1. Olfactory – treat smell
2. Optic - menace
3. Oculomotor – PLR, Doll’s eye
4. Trochlear
5. Trigeminal – sensation to face, symmetry of muscles, medial blink
6. Abducens – Doll’s eye
7. Facial - sensation to face, symmetry of muscles, lateral blink
8. Vestibulocochlear - hearing
9. Glossopharyngeal - swallowing
10. Vagus - swallowing
11. Accessory – normal neck musculature
12. Hypoglossal – normal tongue musculature

Question 7

Percent of fibers that cross in the optic chiasm in horses and how this affects vision

Answer 7

80-90% - horse has small binocular field

Question 8

Why does CN III come from two places?

Answer 8

CN III motor nucleus and Edinger-Westphal nucleus. (Motor and parasympathetic)

Question 9

Restrictions of which joint(s) most commonly affect the cranial nerves?

Answer 9

TMJ and hyoid