Sensory Pathway II

Question 1

Conscious proprioreception

Answer 1

-sensory travels through dorsal funiculus (2 parts)
>pelvic limb sensory travels through fasciculus gracillis (medial)
>thoracic limb sensory travels through the fasciculus cuneatus (lateral)

-will synapse in medulla of brainstem
-from medulla will synapse in thalamus
-from thalamus will synapse on somatosensory cortex

Question 2

Conscious proprioception

Answer 2

-sensory input originates from one side of the body, then crosses over (decussates) after synapsing in medulla, and continues on the contralateral side
*crossover occurring in brain

Question 3

Subconscious proprioception pathways

Answer 3

-Has two pathways from the sensory neuron
>Dorsal spinocerebellar tract through lateral funiculus (no cross over, runs on same side of spinal cord)
>ventral spinocerebellar tract through lateral funiculus (crossover present and moves on opposite side of spinal cord)
**crossover occurring in spinal cord
-will travel to cerebellum

Question 4

Spinocerebellar tracts

Answer 4

-all present in the white matter of spinal cord (all myelinated)
-therefore most superficial and most prone to damage

Question 5

Assessment of Proprioception

Answer 5

1.Examine their Gait – incoordination=ATAXIA
2.Challenge their proprioception (circling, stepping up onto or over obstacles)
3. Test postural reactions/responses (knuckling, hopping, wheelbarrowing, hemi-walking)

Question 6

Exteroception

Answer 6

-detection of sensations from outside the body (external stimuli)
-non-painful stimuli
**animals need this information to detect their external environment and sense potential dangers

Question 7

Enteroception

Answer 7

-detection of stimuli from within the body
-uses the same pathways as exteroception but the receptors are different

Question 8

Exteroception receptors (mostly in skin)

Answer 8

-pressure receptors
- light touch receptors
- vibration receptors
- temperature receptors
- hair receptors- more numerous in most animals
- tylotrich receptors (vibrissae, whiskers)

Question 9

Dermatomes

Answer 9

-spinal nerves at every segment of spinal cord that gives rise to peripheral nerves. These nerves are divided into dermatomes (areas to test nerves at that level and determine where signals have been lost)

Question 10

Face and muzzle

Answer 10

-cranial nerves
-large area of sensory detection

Question 11

Exteroception pathway

Answer 11

-axons at dorsal funiculus, synapse at medulla where crossover occurs, then thalamus, then reaches cerebral cortex (somatosensory cortex)

***similar to conscious proprioception pathway