Somatosensory system Flashcards
What is the role between the ventral and the dorsal column?
The ventral column manages the muscles and the dorsal column manages sensory receptors
What does the somatosensory system register?
- touch
- temperature
- pain
- pressure
- vibration
- limb position
- itch
Where is the primary somatosensory cortex located?
The primary somatosensory cortex is
located dorsal of the central sulcus.
The somatosensory cortex receives imput from 2 types of fiber, which ones and what is the difference?
Two types of dorsal root afferents:
Touch and pressure: mechanosensory fiber, detect stimulation using mechoreceptors.
Nocireceptive afferent: pain and temperature
afferent, detect stimulation in free nerve endings
Where do the mechanosensory and the pain an temperature fibers have their cell bodies?
dorsal root ganglium
What is the difference in routes between the pain and sensory pathway and the touch an pressure pathway(mechanosensory fiber)
the touch and pressure pathway changes its side later on and the pain and sensory dessucates immediatly
How does the mechanosensory fiber channels work?
Touch is detected as a change in pressure on the skin. Change of phospholipid pressure in the membrane leaflet operates opening/closing of ion channels
When there is a small/big receptive field, there is higher/lower precision and less or more sensitive per receptive field.
When there is a small receptive field, there is higher precision and less sensitive per receptive field.
What are the receptive fields of the Merkel, Meissner, Pacinian and Ruffini complex?
Merkel: 9 mm so small
Meissner: 22mm so small
Pacinian: entire finger or hand so big
Ruffini: 60mm so big
If you needed to find out which piece of sandpaper has a finer grain, how could you best detect this?
You rub the sandpaper together, because then you use more corpuscles. Not only the Merkel and the Meissner, but also the Ruffini and the Pacinian
What does proprioception mean?
sensory information of the body itself, where is the position of the limbs?
Name the 2 receptors for proprioception
Muscle spindels: changes in muscle length
Golgi tendon: changes in muscle tension
How does proprioception projects?
Afferents of proprioreceptors project to the ventral horn (e.g. reflexes) and through Clarke’s nucleus to the cerebellum
(timing of voluntary movement) as well as the thalamus.
What do you stimulate when you learn to play the guitar?
You stimulate the cerebellum (learned behaviour tasks)
What is a dermatome?
The innervated area of a sensory axons of
a single dorsal root ganglion. Sensory information comes in from the body here.
