PHGY 209 Lecture Notes - Lecture 17: Lamellar Corpuscle, Merkel Nerve Ending, Bulbous Corpuscle
25 Nov 2017
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Document Summary
Somatic (bodily) sensation is mediated by several types of receptors. Touch: mechanoreceptors with specialized end organs that surround the nerve terminal. These end organs allow only selective mechanical information to activate the nerve terminal. Superficial layers: meissner"s corpuscle (a): fluid-filled structure enclosing the nerve terminal. Sensitive to light stroking and fluttering, light vibrations: merkel disk (b): small epithelial cells surround the nerve terminal. Deep layers: pacinian corpuscle (d): large concentric capsules of connective tissue surround the nerve terminal. Sensitive to strong vibrations: ruffini endings (e): nerve endings wrap around a spindle-like structure. Sensitive to stretch and bending of the skin (shape of an object) Thermoreceptors are free nerve endings containing ion channels that responds to different temperature ranges: cold afferents: 0-35c (activated by menthol, warm afferents: 30-50c (activated by capsaicin in hot peppers, and ethanol, extreme temperatures activate pain receptors. Nociceptors are free nerve endings containing ion channels that open in response to intense mechanical deformation, excessive temperature or chemicals.
