Laboratory 6: Human Physiology — Sensations, Reflexes and Reactions (Vocabulary Flashcards)

Vocabulary flashcards covering eye and vision anatomy, ear and hearing, taste and smell, skin sensation, adaptation, and common reflex tests.

Cornea

Transparent front surface of the eye that refracts light rays and protects the eye.

Iris

Pigmented muscle that controls the size of the pupil to regulate light entry.

Pupil

Opening in the center of the iris through which light enters the eye.

Lens

Transparent structure that focuses light onto the retina by changing shape via the ciliary body.

Retina

Light‑sensitive layer at the back of the eye where photoreceptors reside and images are formed.

Cones

Photoreceptors responsible for color vision in bright light; concentrated in the fovea centralis.

Rods

Photoreceptors responsible for vision in dim light; more sensitive in low light and peripheral vision.

Sclera

Tough outer connective tissue that protects the eye and provides attachment for eye muscles.

Choroid

Vascular layer between the sclera and retina that supplies blood to the retina.

Vitreous humor

Gel-like fluid filling the vitreous chamber that helps maintain eye shape and light transmission.

Aqueous humor

Fluid in the anterior chamber that nourishes eye tissues and maintains intraocular pressure.

Optic nerve

Nerve that transmits visual information from the retina to the brain.

Fovea centralis

Central retinal region densely packed with cones; site of sharpest vision.

Ciliary body

Smooth muscle that changes the lens shape for focusing.

Conjunctiva

Mucous membrane covering the sclera and lining the eyelids; protects and lubricates the eye.

Visual acuity

Sharpness or clarity of vision, measured with an eye chart.

20/20 vision

Normal visual acuity; what a person with normal vision can read at 20 feet.

Myopia

Nearsightedness; image focuses in front of the retina, distant objects appear blurred.

Hyperopia

Farsightedness; image focuses behind the retina, near objects appear blurred.

Blind spot

Region where the optic nerve exits the retina; lacks photoreceptors and cannot form images.

Auricle (pinna)

External, visible part of the ear that collects sound waves.

External auditory canal

Channel directing sound waves toward the eardrum.

Tympanic membrane

Eardrum; vibrates in response to sound waves.

Malleus

Hammer-shaped ossicle in the middle ear; first of the three auditory bones.

Incus

Anvil-shaped ossicle in the middle ear; middle of the three auditory bones.

Stapes

Stirrup-shaped ossicle in the middle ear; final ossicle transmitting vibrations to the inner ear.

Cochlea

Snail-shaped inner ear structure that converts vibrations into neural impulses.

Cochlear nerve

Nerve that carries auditory information from the cochlea to the brain.

Semicircular canals

Inner ear structures that help maintain balance and detect head movements.

Eustachian tube

Channel that equalizes middle ear pressure with the atmosphere.

Sensorineural hearing loss

Hearing loss due to damage to inner ear receptors or the cochlear nerve; often permanent.

Conductive hearing loss

Hearing loss due to obstruction of sound conduction in the outer or middle ear.

Weber test

Tuning fork test used to distinguish sensorineural vs conductive deafness by assessing sound localization on the head.

Rinne test

Tuning fork test comparing bone conduction to air conduction to identify conductive deafness.

Romberg test

Balance test assessing proprioception and vestibular function by standing with feet together (eyes open/closed).

Olfactory receptors

Receptors in the nasal cavity that detect airborne chemicals (smell).

Taste buds

Taste receptor organs on the tongue involved in gustation.

Olfactory bulb

Brain structure that processes smell signals from the olfactory receptors.

Chemoreception

Sensation of chemicals in the environment, including smell and taste.

Mechanoreceptors

Receptors that respond to mechanical stimuli such as touch, pressure, stretch, and vibration.

Two-point discrimination

Test of tactile acuity; smallest distance at which two points are felt as distinct.

Adaptation

Decline in receptor response to a prolonged stimulus as the stimulus is maintained.

Pupillary reflex

Autonomic reflex causing pupil constriction or dilation in response to light intensity.

Reaction time

Time between a stimulus and the initiation of a response; often measured with a ruler.

Patellar reflex

Knee-jerk stretch reflex; a simple spinal reflex involving the quadriceps muscle.