Somatosensation Flashcards
Sensory Adaptation
decrease in the responsiveness of our sensory system over time to a constant stimulus (down regulation of a sensory receptor)
Amplification
1) Up Regulation
2) increase in the responsiveness of our sensory system to a stimuli
Temperature
1) Thermoreception
2) Slow
3) Rely on Trpv1 receptor to sense temperature
Pressure
Mechanoception
Pain
1) nociception
2) Slow
3) Trpv1 receptor is also sensitive pain
Position
Proprioception (sense of balance - how we know where our body is in space)
What is intensity?
1) How quickly the neurons fire
2) Low intensity - slow firing of neurons
3) high intensity - fast firing of neurons
What are the 3 types of timing a neuron can encode for?
1) non-adapting: fire constant AP
2) Slow Adapting: starts firing very fast, then slows down
3) Fast adapting: starts firing immediately, stops, then starts once stimuli stops
What happens if amplification is presents without down regulation?
cell may become over excited to die (down regulation causes balance so the cell and brain or constantly overwhelmed)
Somatosensory Homunculus
1) Sensory strip that is a map of your body in your brain
2) Located in the somatosensory cortex of the parietal lobe
How does the Somatosensory Homunculus work?
1) There is a sensory strip located in your brain
2) Different areas of the body have signals that go to specific regions of the strip
How does Proprioception work?
1) all of our muscles have spindles (receptors) hat send signals to the spinal cord, which eventually reach the brain
2) Spindle has a protein that is sensitive to stretching
3) As a muscle contracts, the spindle senses the muscles stretching, and then stretches itself
4) When the protein inside the spindle contracts, it sends a signal to the brain (which tells how much each and every one of our muscles is contracted)
Kinaesthesia
sense of movement of body in space (vs. proprioception which is just the position and balance of your body in space)
Proprioception is also thought of as a __________ awareness of your body inspace
cognitive (Subconscious.Not always thinking about it.)
Kinaesthesia is more ______________ than proprioception.
behavioral (You teach yourself how to move to successfully complete the task at hand.)
How does trypv1 receptor work for temperature?
1) There are thousands of these in membranes of cells
2) heat causes conformational changes in this protein
3) When a cell gets “poked” thousands of cells get broken up, which releases different molecules that will look for and bind the Trypv1 receptors
4) This causes a conformation change in the receptor
5) When the conformation change occurs,, this activates the cell, which sends a signal to the brain
6) Signal to the brain is sent via a nerve; which contains 3 types of fibers
What are the three types of fibers in a nerve that sends the brain a signal about temperature?
1) A-Beta
2) A-Delta
3) C fibres
A-Beta fibers
1) Fast Fibers
2) Covered in myelin (insulator that allows AP to travel quickly)
3) Large diameter - less resistance
Immediate feeling of temperature change
A-Delta Fibers
Medium diameter with less myelin
After effect: pain that comes with stimuli
C Fibres
Smallest diameter with no myelin
Lingering sensation from the after effect
How does trypv1 receptor work for pain?
1) Same is with termperature except for when cells break apart, they release capsaicin (only in the mouth - in your tongue, example used when you eat a jalapeno).
2) Capsaicin looks for and binds to Trypv1 receptor and triggers same response as a change in temperature
What does affective describe?
experience of emotions
What does do sensory components describe?
Intensity of pain
The gate control theory asserts:
non-painful input closes the “gates” to painful input (preventing sensation from traveling up CNS, therefore suppressing the pain you should otherwise be feeling)
(i.e. when you get a paper cut and start waving your hand, when you are waving your hand, the pain seems to decrease. If you stop the motion of waving your hand the intensity of the pain returns)
