Reflex, Eyes, & Ears - A&P

Patellar Reflex

A reflex extension of the leg resulting from a sharp tap on the patellar tendon.

Crossed Extensor Reflex

Opposite limb supports body during withdrawal of injured limb.

Pupillary Reflex

Both pupils constrict when light is directed at one eye.

Intrinsic Reflexes

Reflexes we are born with for primitive protection.

Learned Reflexes

Result from practice or repetition.

Two Point Threshold

Minimum distance necessary between two points of stimulation on the skin such that the points will be felt as two distinct stimuli.

Tactile Localization

The ability to determine which portion of the skin has been touched.

Extrinsic Eye Muscles

Six muscles attach to the outer surface of the eye and produce eye movements.

Conjunctiva

Delicate membrane lining the eyelids and covering the eyeball.

Eyelids

Two movable flaps of skin which cover and uncover each eyeball.

Eyelashes

Nerve endings of follicles initiate reflex blinking.

Lacrimal Gland

Produces tears.

Lacrimal Sac

Structure that collects tears before emptying into the nasolacrimal duct.

Nasolacrimal Duct

Passageway for tears from the lacrimal sac into the nose.

Sclera

White part of the eye.

Cornea

The clear tissue that covers the front of the eye.

Choroid

Middle, vascular layer of the eye, between the retina and the sclera.

Ciliary Body

Rng of tissue behind the peripheral iris that is composed of ciliary muscle and ciliary processes.

Iris

A ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil opening.

Pupil

The adjustable opening in the center of the eye through which light enters.

Retina

Light sensitive layer of the eye; contains rods and cones.

Tapetum Lucidum

Iridescent layer found in nocturnal animals for maximizing vision under low intensity light

Vitreous Humor

The transparent jellylike tissue filling the eyeball behind the lens.

Pinna

The visible part of the ear.

External Auditory Canal

The ear canal; leads to the tympanic membrane.

Tymphanic Membrane

Eardrum; consists of ossicles (malleus, incus and stapes).

Malleus

Hammer; first of the three auditory ossicles of the middle ear.

Incus

Anvil; middle of the three auditory ossicles of the middle ear.

Stapes

Stirrup; last of the three auditory ossicles of the middle ear.

Oval Window

Membrane at the entrance to the cochlea through which the ossicles transmit vibrations.

Round Window

Located just below the oval window; equalize pressure in the inner ear.

Eustachian Tube

Connects the middle ear with the nasopharynx and allows passage of air.

Bony Labyrinth

Passageways in temporal bone.

Membranous Labyrinth

Membrane-covered tubes inside the bony labyrinth.

Endolymph

Fluid within the labyrinth of the inner ear.

Perilymph

Fluid that very closely resembles spinal fluid but found in the cochlea.

Vestibule

Central cavity of the bony labyrinth that detects linear acceleration and connects the cochlea and semicircular canals

Semicircular Canals

Three fluid-filled canals in the inner ear responsible for our sense of balance.

Cochlea

A coiled, bony, fluid-filled tube in the inner ear through which sound waves trigger nerve impulses.

Scala Vestibuli

The upper bony passage of the cochlea.

Scala Tympani

Extends from apex of cochlea to round window; lower portion.

Cochlear Duct

Fluid filled cavity within the cochlea that vibrates when sound waves strike it.

Organ of Corti

Tissue containing the hair cells necessary for hearing.

Vestibulocochlear Nerve

Primarily focuses on hearing and balance (sensory).

Conductive Hearing Loss

Hearing impairment caused by interference with sound or vibratory energy in the external canal, middle ear, or ossicles.

Sensorineural Hearing Loss

The most common form of hearing loss, also called nerve deafness; caused by damage to the cochlea's receptor cells or to the auditory nerves.

Static Equilibrium

A condition where there are no net external forces acting upon a particle or rigid body and the body remains at rest or continues at a constant velocity.

Dynamic Equilibrium

Result of diffusion where there is continuous movement of particles but no overall change in concentration.

Vertigo

Condition of dizziness, "room spinning".

Nystagmus

Involuntary rapid eye movements.