Mechanosensation Flashcards
What is mechanosensation?
Touch, pressure, vibration
What is proprioception
Joint and muscle position
What is thermosensation
Temperature
What is nociception
Pain
What are the different types og high threshold unita
High threshold mechanoreceptors, thermal nociceptors, Chemical nociceptors, and polymodal nociceptors
Slowy adapting response
Continuos information to CNS while terminal deformed.
E.g. stretch receptors
Rapidly adapting response
Detects change in stiumuls strength.
No of impulses proportional to rate of change of stimulus
Very rapidly adapting response
Respodns only to very fast movement e.g vibrations
A-alpha neurons
Thick myleination, propiroceptors in the skin
A-beta neurons
Moderate myelination, Mechanoreceptors of the skin
A-delta neurons
Thin myelination, fast pain and cool temps
C neurons
No myelination, slow pain
Receptive field
The region, that when stimulated with an adequate stimulus, causes a response in that neuron
Cutaneous receptors
Free nerve endings
Meissner’s corpuscles
Merkel’s discs
Hair-end organs
Ruffini endings
Pacinian curpuscles
(fuck me man, her racks perfect)
Where do sensory neurons enter the spinal cord
Dorsal horn
What is a dermatome
Area of skin innervated by the left and right dorsal roots of a signle segment
How can dermatomes be mapped
Set of 4 bands on the body, seen clearer on all fours
When do A-alpha and beta fibres cross to the contralateral side of the spinal cord?
2nd order neuron
when do A-delta, C fibres cross over
Bottom of the spinal cord
What are the two components of the dorsal colum?
Fasciculus gracilis, Fasciculus cuneatus
What is the major route by which touch and proprioception information ascends into the cebral cortex
Dorsal column medial leminiscal pathway
What are the steps of the DCML pathway
- PA neuorns enter dorsal horn and form branches which synapse in the dorsal horn with second order neurons, and an ascending component that synapses in the medulla
- Axons of second order neurons cross in the great sensory decussation and ascend into the medial lemniscus to the ventroposterolater (VPL) nucleus of the thalamus
- Third order neurons project to the primary somatosensory cortex (S1) via the posterior interal capsule
What is the secondary somatosensroy cortex
Recieves and integrates info from S1 and other cortical areas and sub-cortical areas
What is S2 important for
tactile touch and object recognition
