Descending (UMN) Tracts

Question 0

Signs of damage?

Answer 0

spastic paresis/paralysis
normo-hypertonia
normo-hyperreflexia
disuse atrophy

Question 1

Where in the spinal cord?

Answer 1

lateral and ventral funicului

Question 2

Lateral corticospinal tract

Answer 2

Pyramidal system
Cell bodies in cortex of frontal lobe
100% crossover in medulla
Excitatory to LMNs of flexors on opposite side
Unimportant in domestic animals on flat surface

Question 3

Rubrospinal tract

Answer 3

Extrapyramidal system
Cell bodies in red nucleus of midbrain
Excitatory to LMNs of flexors on opposite side
Initiate and regulate voluntary mvmt

Question 4

Tectospinal tract

Answer 4

Extrapyramidal system
Cell bodies in rostral colliculus of tectum of midbrain
Excitatory to LMNs of flexors in neck on opposite side
Sight avoidance reflex and sight tracking

Question 5

Tectotegmental tract

Answer 5

Extrapyramidal system
Cell bodies in tectum (rostral colliculus) and tegmentum of midbrain
Sympathetic control of eye and pupillary dilation
Control GVE LMNs in intermediolateral grey horn T1-T4
Damage –> Horner’s Syndrome

Question 6

Horner’s Syndrome

4 clinical signs

Answer 6

lack of sympathetic innervation to eye

1. constricted pupil / miosis
2. enophthalmus (eye sunken into socket)
3. 3rd eyelid protrusion - bc of enophthalmus
4. ptosis - bc of enophthalmus

Question 7

Pontine reticulospinal tract

Answer 7

Extrapyramidal system
Cell bodies in tegmentum of pons
Excitatory to LMNs of extensors
Controls posture and locomotion

Question 8

Medullary reticulospinal tract

Answer 8

Extrapyramidal system
Cell bodies in tegmentum of medulla
Inhibitory to LMNs of extensors
Regulates posture and locomotion, GVE LMNs, and muscle spindles

Question 9

Lateral vestibulospinal tract

Answer 9

Extrapyramidal system
Cell bodies in vestibular nuclei of vestibular trigone in medulla
Excitatory to LMNS of extensors on same side,
Inhibitory to LMNs of flexors on same side,
Inhibitory to LMNs of extensors on opposite side
Adjusts posture in relation to head mvmts,
Regulates balance and equilibrium,
Controls normal standing posture

Question 10

Medial longitudinal fasciculus

Answer 10

Extrapyramidal system
Cell bodies in vestibular nuclei of vestibular trigone of medulla
Controls LMNs of CNs III, IV, VI
Adjusts posture in relation to head mvmts