Lecture 3: Dorsal Column Sensory Flashcards
What are alpha-beta nerve cells involved with?
Touch, vibration, conscious proprioception
Where do alpha beta nerve cells run in the spinal cord?
Dorsal funiculus
Hair cell receptors
Unencapsulated; hairy skin; deep field; activated via hair movement
Meissner’s Corpuscles
Hairy and glabrous skin; Surface small field; activated by light touch, texture, low freq vibrations; adapts quickly
Merkel’s Disk
Hairy and glabrous skin; Surface small field; activated by light touch and pressure; only nerve cell in epidermis; adapts slowly
Pacinian Corpuscles
Hairy and glabrous skin; deep large field, activated by deep pressure and high freq vibrations; like onion; adapts quickly
Ruffini endings
Glabrous (hairy?) skin only; deep large field; activated by deep pressure and stretch; adapts slowly
How do people tell where their joints and limbs are?
Alpha-beta nerves are located in joints and convey conscious proprioception to brain
What receptors are involved most in 2 point discrimination?
Meissners and Merkels because both are superficial; highest concentration in lips and fingertips
Faciculus Gracillis
Have axons from T7 and below; located medially in dorsal funiculus
Faciculus Cuneatus
Have axons from T6 and above, located more laterally in dorsal funiculus
How are axons from body parts arranged in the dorsal column?
Lower body parts are located more medially
What will happen with a lesion in the dorsal column?
Loss of ipsilateral touch, vibration, and conscious proprioception
Where do fasciculus cuneatus axons synapse?
Ipsilateral nucleus cuneatus
Where do fasciculus gracillis axons synapse?
Ipsilateral nucleus gracillis
