AP Psych Unit 1 Biology Part 2

circadian rhythm

the biological clock; regular bodily rhythms that occur on a 24-hour cycle

REM sleep

a stage of sleep characterized by rapid eye movements and a high level of brain activity

sleep apnea

a sleep disorder characterized by temporary cessations of breathing during sleep and repeated momentary awakenings

Depressants

drugs (such as alcohol, barbiturates, and opiates) that reduce neural activity and slow body functions

Stimulants

Drugs (such as caffeine, nicotine, and the more powerful amphetamines, cocaine, and ecstasy) that excite neural activity and speed up body functions

Hallucinogens

psychedelic ("mind-manifesting") drugs, such as LSD, that distort perceptions and evoke sensory images in the absence of sensory input

sensation

the process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment

transduction

The process of converting outside stimuli, such as light or sound, into neural activity

absolute threshold

the minimum stimulation needed to detect a particular stimulus 50 percent of the time

signal detection theory

a theory predicting how and when we detect the presence of a faint stimulus amid background stimulation (noise). Assumes there is no single absolute threshold and that detection depends partly on a person's experience, expectations, motivation, and alertness.

subliminal

below one's absolute threshold for conscious awareness

difference threshold

The minimum amount of difference that can be detected between two stimuli

cornea

The clear tissue that covers the front of the eye

pupil

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

iris

a ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the pupil opening

lens

the transparent structure behind the pupil that changes shape to help focus images on the retina

retina

the light-sensitive inner surface of the eye, containing the receptor rods and cones plus layers of neurons that begin the processing of visual information

accommodation

the process by which the eye's lens changes shape to focus near or far objects on the retina

rods

retinal receptors that detect black, white, and gray; necessary for peripheral and twilight vision

cones

retinal receptor cells that are concentrated near the center of the retina and that function in daylight or in well-lit conditions; detect fine detail and color sensations

optic nerve

the nerve that carries neural impulses from the eye to the brain

blind spot

the point at which the optic nerve leaves the eye and no receptor cells are located there.

frequency theory

in hearing, the theory that the rate of nerve impulses traveling up the auditory nerve enabling us to sense its pitch

eardrum

a thin membrane that marks the beginning of the middle ear; sound waves cause it to vibrate

Eustachian tube

A narrow tube between the middle ear and the throat that serves to equalize pressure on both sides of the eardrum

cochlea

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

sensorineural hearing loss

hearing loss caused by damage to the cochlea's receptor cells or to the auditory nerves; also called nerve deafness

conductive hearing loss

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

Nociceptors

pain receptors

gate control theory

theory that explains how the nervous system blocks or allows pain signals to pass to the brain

gustation

sense of taste

olfaction

sense of smell

kinesthetic sense

sense of the location of body parts in relation to the ground and each other

vestibular sense

the sense of body movement and position, including the sense of balance