ACB 406.3 Lecture Notes - Lecture 17: Stratified Squamous Epithelium, Tympanic Cavity, Eardrum

• School: U of S
• Department: Anatomy and Cell Biology
• Course: ACB 406.3
• Professor: Helen Nichol

Document Summary

All vertebrates have taste buds w/ the exception of hagfish: hagfish have individual sensory cells on the skin (merkel-like cells) Induced from ecto or endodermal epithelia of oropharynx. Humans: sweet, salty, bitter and acid (sour: there"s also umami (glutamate) Only the sensory cells synapse w/ afferent sensory neurons. Lower vertebrates designed to detect low frequencies. No organ of corti and no pinna (external ear) Complex otoliths w/ an array of sensory cells in maculae (e. g. fish: a(cid:374) (cid:862)auditor(cid:455) reti(cid:374)a(cid:863) that gives 3 di(cid:373)e(cid:374)sio(cid:374)al i(cid:374)for(cid:373)atio(cid:374) Birds (owls) and mammals (bats) that use hearing for prey detection, the part of the cochlea that detects key frequencies is bigger auditory fovea. Tympanic membrane (ear drum) separates the external ear from the air-filled tympanic cavity. Tympanic cavity contains the malleus, incus and stapes bones. Layers of the membrane: outside surface of the tympanic membrane stratified squamous epithelium (same as external auditory meatus, has ct in the middle. Inner surface of membrane simple cuboidal epithelium.