somatosensory system Flashcards
sensitivity to stimuli interacting with ones body (touch temp pain)
exteroception
ability to sense position, location and orientation
proprioception
stimuli originating from inside body
interoception
information from ___ is carried by dorsal root ganglia and spinal cord
trunk
information from ___ is carried by cranial nerves
face and head
dorsal root ganglia contain __ ___ __ that innervate skin, muscles, joints and organs
neuronal cell bodies
___ ___ of nerve fibers (DRG) involved in touch are encapsulated by special end organs
peripheral process
DRG neurons are
pseudounipolar
information carried by DRG enters in ___ spinal cord in each of the regions
dorsal
receptor type and fiber which carries proprioception
muscle spindle, and Ia, II (large and well myelinated); fast
receptor type and fiber which carries touch
merkel, meissner and ruffini cells (end organs), A beta (well myelinated not as big)
receptor type and fiber which carries pain and temperature
free nerve endings, A delta
receptor type and fiber which carries pain, temp, itch
free nerve endings, C fibers (smallest and unmyelinated)
cell that responds to mechanical stimulus
mechanoreceptors
the nerve endings of mechanoreceptors respond to stimulus by
stretching (as plasma membrane stretches it opens Na channels –> depolarization)
depolarizing potenial that accomponies stimulation of a sensory nerve (varies according to strength of stimulus)
receptor potential
part of a sensory field that can elicit neuronal responses when stimulated (each neuron has one but size and freq. can be different)
receptive field
decline of electrical response in a receptor cell over time, even thouhg stimulus id still present
adaptation