chapter 3: PNS Flashcards
1
Q
3 types of sensory endings
A
- exteroceptive ending
- proprioceptive ending
- interoceptors
2
Q
peripheral proces has 2 categories of sensory endings and afferent neurons
A
- somatic afferents: skin, bones, muscles, connective tissue
- visceral afferents: internal organs of circulatory, respiratory, alimentary, excretoy, reproductive systems
3
Q
peripheral proces has 2 categories of efferent neurons
A
- somatic efferents = motor neurons: in ventral gray horn of spinal cord & in motor nuclei of cranial nerves
- visceral efferents = in autonomic system: to smooth muscle, cardiac muscle & secretory cells
4
Q
types of cuteneous sensory endings
A
- free nerve ending
- merkel ending
- peritrichial nerve ending
- ruffini ending
- pacinian corpuscle
- meissner’s tactile corpuscle
- end bulbs of Krause
5
Q
4 elementary sensations
A
touch
warmth
cold
pain
6
Q
modalities =
A
= types of sensations perceived from the skin
- fine (discriminative) touch
- vibration
- light touch
- temperature
- pain
7
Q
nociceptors =
A
= painful sensations, received by free nerve endings
- high- threshold mechanoreceptors
- polymodal nociceptors
- lowerd pain threshold
8
Q
functions of neuromuscular spindles
A
- receptor of stretch reflex
- basis for tendon reflexes
- important role in muscle action that results from activity of brain
- gamma reflex loop consists of gamma motor neuron, muscle spindle, sensory neuron & alpha motor neuron
9
Q
peripheral nerves have 3 connective tissue sheaths
A
- epineurium
- perineurium
- endoneurium
10
Q
function of myelinated nerve fibers
A
- electrically insulates internodal parts of axon
- at each node are irregular edges of cytoplasmic portions of Schwann cells with narrow space between them
- axolemma is in contect with extracellular space
- voltage- gated sodium channels are present
- favourable for saltatory conduction
