Peripheral Nerve Endings Flashcards
Adrenergic
Neurons release epinephrine / norepinephrine
Iris Dilator
Primarily adrenergic. Adrenergic to cholinergic 3:1
Innervation is primarily sympathetic
Iris Sphincter
Adrenergic to cholinergic 1:6
parasympathetic
Afferent
axons in peripheral nerves are of three classes and have a variety of kinds of endings
A beta
A delta
C dorsal root
Sensory endings types
Free endings
encapsulated endings
Rapidly adapting (dynamic) : Respond only at onset (smell)
Slowly adapting (static) : respond continuously (hear)
Slowly adapting
slow: merkel and ruffini corpuscle end-organs, some free nerve endings
intermediate adapting: Some free nerve endings are intermediate adapting
Rapidly adapting: stuff. (said in class we dont have to memorize)
Sensory functions:
Nociception: painful tissue injury conducted by C fibers. Slowly adapting
Thermal: hot and cold
Mechanical: around hair follicles
Itching
Merkel Cells
Not neurons but associated with them. Has Tonic receptors for sustained light touch, and sensing objects texture.
Perineurium forms
endoneurium includes…
capsule of encapsulated nerve endings.
collagen fibers
Ruffini corpuscles
In dermis and subcutaneous tissues of thick skin.
primary mechanoreceptors of periodontal ligament
Meissner’s corpuscle
Encapsulated by perineural and schwann cells
rapidly adapting, sensitive to light touch and vibration
neuromuscular spindle
As extrafusal fibers stretch, intrafusal fibers detect stretch and stop from tearing.
Have both sensory and motor innervation
Type 1a sensory fibers have annulospiral endings
Type II sensory fibers have “flower-spray” endings that attach to the striated parts of intrafusal fibers
Gamma = intrafusal
Alpha = extrafusal
Go back to this slide (37)
Spindles in human jaw muscle
Temporalis Muscle: large
Masseter Muscle: medium
Medial Pterygoid Muscle: small
