14 – Sensory Pathways III Flashcards
Sensory pathway depth compared to motor pathway depth:
-sensory is more superficial
>can see proprioception symptoms before some motor symptoms
Fasciculus gracilis:
-pathway of conscious proprioception for the pelvic limb
-medial dorsal funiculus
-spinal segments caudal to T6
Fasciculus cuneatus:
-pathway of conscious proprioception for the thoracic limb
-lateral dorsal funiculus
-spinal segments cranial to T6
Proprioception:
-awareness of body in space
Exteroception:
-detection of external stimuli
Enteroception (interoception):
-detection of internal stimuli
>pressure, touch, T
Nociception:
-detection of noxious stimuli (painful, unpleasant, harmful)
-a stimuli that is forceful enough that it could cause tissue damage
Ex. mechanical pressure (not light tough), temperature
*have BOTH a mechanical and a behaviour response
What are the receptors of nociception?
-NO specialized receptors
*bare nerve endings
>located throughout body in HIGH numbers
**have a HIGH threshold=not easily activated
Nociception ‘receptors’ located throughout the body in high numbers:
-skin (superficial/deep)
-muscle
-GIT
What are the brain regions of nociception?
-cerebral cortex: somatosensory cortex
*sensory always synapses on an interneuron at the level of the sensation
>go to OPPOSTIE side
What are the spinal pathways of nociception?
1.Spinothalamic tract: lateral and ventral
2. Multi-synaptic pathway
*sits deeper
Spinothalamic tract:
-interneurons crosses-over
-some also stay ipsilateral because the info is so important
Lateral spinothalamic tract:
-lateral funiculus
Ventral spinothalamic tract:
-ventral funiculus
Multi-synaptic pathway:
-grey matter interneurons receive impulses from sensory neurons
>send signals to lateral and ventral funiculi
-‘multiple’ interneurons along the spinal cord
*all end up in the brain and synapse on various nuclei
