Touchy Fili Flashcards
What is the somatic sensation responsible for?
Touch, itch, pain
What are the two major subsystems of somatic sensation?
Mechanosensory (touch and body position) and temp & pain
What are sensory called? (In regards to polarity)
Pseudounipolar (looks kind of like a sentry gun with the head being the soma)
Where are the cell bodies of sensory neurons?
Dorsal root ganglion
What are the four receptor groups based on function?
Mechanoreceptors, nociceptors, pruriceptors, & thermoceptors
What are mechanoreceptors in charge of?
Touch
What are nociceptors in charge of?
Pain
What are pruriceptors in charge of?
Itch
What are thermoreceptors in charge of?
Temperature
What are the two groups of receptors based on morphology?
Free nerve endings and encapsulated
What are some characteristics of free nerve endings?
They are unmyelinated terminal branches and they consist of nociceptors and thermoreceptors
What are some characteristics of Encapsulated types of receptors?
They are myelinated and are only mechanoreceptors for touch
What is the sensory transduction pathway?
Stim deforms skin -> receptor membrane permeability is altered -> depolarization occurs -> AP is triggered
What determines the QUALITY of the stimulus?
Types of receptors that are activated
What determines the QUANTITY of stimulus?
The rate of AP discharge»_space;> adaptation
What are mechanoreceptors sensitive to?
Physical distortion
How sensitive are mechanoreceptors in the skin?
Extremely (low threshold)
Which mechanoreceptors have small receptive fields?
Meissner’s corpuscles and Merkel’s disks
Which mechnoreceptors have large receptive fields?
Pacinian corpuscles and Ruffini’s endings
Which mechanoreceptors rapidly adapt? (Aka quick cease fire)
Messneir and Pacinian corpuscles
Which mechanoreceptors have slow adaptation? (Sustained response as long as stim remains)
Merkel’s disk and ruffini’s endings
When do Pacinian corpuscles have the largest receptor potential?
Onset and offset (basically when you touch and then u untouch)
What are the three types of mechanosensitive ion channels?
Lipid membrane stretch sensitive, extracellular protein force sensitive, cytoskeleton force sensitive
Why do fingertips have the most spatial resolution?
- Higher density of mechanoreceptors
- More Merkel’s disks
- More brain tissue is devoted to it
- Special neural mechanisms are devoted to high res discriminations
