STUDY GUIDE FOR CHAPTER 8

In addition to the definitions below, see also the summary on pages 263-264.

Interoception - sensitivity to internal stimuli (usually unconsciously)

Proprioception - sensitivity to the stretch or contraction or position in one’s own musculoskeletal system

Exteroception - sensitivity to external stimuli

Chemoreceptors - receptors for the chemical senses (smell and taste)

Olfactory receptors - smell receptors, sensitive to chemicals (usually airborne) in low concentrations

Taste buds - structures in the tongue and palate, sensitive to chemicals dissolved in fluids in the mouth

Photoreceptors - organs or cells sensitive to light

Sclera (scleroid) - outer coating of connective tissue around the eyeball, continuous with the dura mater

Choroid - the second layer of connective tissue covering the eyeball, continuous with the ciliary body

Cornea - the transparent covering of the front of the eye

Astigmatism - irregularities in the roundness (curvature) of the cornea

Ciliary body - circular ring of smooth muscle and connective tissue that holds the lens in place, controls its shape (accommodation), and adjusts the amount of light coming through the pupil

Iris (iris diaphragm) - the colored portion of the ciliary body, capable of opening wider or constricting

Pupil - the opening in the center of the iris diaphragm that regulates the amount of light entering the eye

Refraction - the bending of light rays

Lens - the part of the eye that bends (refracts) and focuses incoming light

Accommodation - ability of the lens to adjust its focal length for near or far vision

Aqueous humor - watery fluid in front of the lens

Vitreous humor - more viscous fluid in the eyeball behind the lens

Retina - the light-sensitive layer coating the inside of the eyeball

Rods - rod-shaped cells in the retina, sensitive to dim light but not to color

Cones - cells with conical portions, sensitive to colors, but only in moderate to bright light

Blind spot - location on the retina where the optic nerve turns inward and receptor cells are absent

Mechanoreceptor - a sense organ that detects mechanical vibrations or sound

Tympanic membrane - membrane at the boundary between the outer ear and the middle ear

Tympanic cavity - another name for the middle ear, housing the auditory ossicles

Ossicles - the small bones (malleus, incus, and stapes) inside the middle ear

Auditory (Eustacian) tube - canal running diagonally from the middle ear civity to the pharynx

Labyrinth - the tortuously shaped bony cavity (bony labyrinth) housing the inner ear, or the connective tissue lining just inside it (the membranous labyrinth)

Oval window (fenestra ovalis) - opening that transmits vibrations of the stapes to the fluid of the inner ear

Cochlea - the coiled portion of the inner ear, devoted to hearing

Organ of Corti - the structure within the cochlea sensitive to sound vibrations

Vestibule - portion of the inner ear devoted to balance

Static equilibrium - any unchanging condition in which no movement takes place in either direction

Dynamic equilibrium - any unchanging condition in which opposite processes or movements are balanced

Semicircular canals - a group of 3 curved canals in which fluid can flow in the vestibule of the inner ear, allowing the detection of balance and acceleration

Crista ampullaris (or neuromast) - small group of hair cells in the ear, sensitive to fluid movements

Macula - a clump of neuromasts (cristae ampullares) in the inner ear