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Chapters 5, 6, 7, & 8

Transduction (sensation)

the process in which a sense organ changes, or transforms physical energy into electrical signals that become neural impulses, which may be sent to the brain for processing

Adaption (sensation)

refers to the decreasing response of the sense organs, the more they are exposed to a continuous level of stimulation

sensations and perceptions

what are the two steps in gathering information about the world?

Sensations

electrical signals reach the brain and are changed into sensations; relatively meaningless bits of information that result when the brain processes electrical signals that come from the sense organs.

Perceptions

brain quickly changes sensations, which you're not aware of, into perceptions; meaningful sensory experiences that result after the brain combines hundreds of sensations.

Too short or too long

when a radio wave is invisible, what is its length?

visible spectrum

one particular segment of electromagnetic energy that we can see because these waves are the right length to stimulate receptors in the eye.

energy (in the form of light waves from the visible spectrum)

what is the most effective stimulus for vision?

cornea

the rounded, transparent covering over the front of your eye. As the light waves pass through this, its curved surface bends, or focuses, the waves into a narrower beam.

pupil

the round opening at the from of your eye that allows light waves to pass into the eye's interior

iris

a circular muscle that surrounds the pupil and controls the amount of light entering the eye. In dim light, this muscle relaxes, allowing more light to enter-the pupil dilates; in bright light, this muscle constricts, allowing less light to enter- the pupil constricts. This muscle ALSO contains the pigment that gives your eye its characteristic color.

lens

a transparent, oval structure whose curved surface bends and focuses light waves into an even narrower beam. The lens is attached to muscles that adjust and curve of the lens, which, in turn, adjusts the focusing.

retina

located at the very back of the eyeball is a thin film that contains cells that are extremely sensitive to light. These light-sensitive cells, called photoreceptors, begin the process of transduction by absorbing light waves.

nearsightedness (myopia)

results when the eyeball is too long so that objects are focused at a point in front of the retina. In this case, near objects are clear, but distant objects appear blurry.

farsightedness (hyperopia)

occurs when the eyeball is too short so that objects are focused at a point slightly behind the retina. In this case, distant objects are clear, but near objects appear blurry.

trichromatic theory

states that there are three types of color receptors that are each receptive to a different primary color and all other colors are produced by variations in the activity of these three receptors.

Just Noticeable Difference

refers to the smallest increase or decrease in the intensity of a stimulus that one is able to detect.

perception

the process of becoming aware of, integrating, and interpreting our sensory stimulation.

consciousness

involves different levels of awareness of a person's thoughts and feelings

suprachiasmatic nucleus

a group of cells in the hypothalamus that regulates the body's circadian rhythms

adaptation

the decreasing response of the sense organs from being continuously exposed to a certain level of stimulation.

rules of organization

specify how an individual's brain combine and organize bits of information into a meaningful perception.

absolute threshold

the intensity level of a stimulus such that a person will have a 50% chance of detecting it.

narcolepsy

a chronic sleep disorder that is marked by excessive sleepiness, usually in the form of sleep attacks throughout the day.

sensation

refers to the receipt of physical stimulation through special sensory organs.

rod (retina)

type of photoreceptor with a rodlike shape that is located primarily in the periphery of the retina. CONTAIN A SINGLE CHEMICAL, rhodopsin, which is activated by small amounts of light (allow us to see in dim light, but only the colors black, white, and shades of grey).

cone (retina)

type of photoreceptor with a conelike shape that is located primarily in the center of the retina in an area called the fovea. CONTAIN THREE CHEMICALS, opsin(s), which are activated in bright light and allow us to see color (ALSO allow us to see details).

optic nerve

nerve impulses flow through this as it exits from the back of the eye. This exit point creates a blind spot that we do not normally see because our eyes are constantly moving and cover any areas that might be in the blind spot.

thalamus

the brain's sensory switchboard, located on top of the brainstem; it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla

primary visual cortex

lies at the very back of each occipital lobe. TRANSFORMS nerve impulses into simple visual sensations, such as texture, lines, and colors.

visual association areas

adds meaning to visual senses/occipital lobe, interpretation of visual input, visual memory

visual agnosia

difficulty in assembling simple visual sensations into more complex, meaningful images.

afterimage

a visual sensation that continues after the original stimulus is removed.

opponent-process theory

says that ganglion cells in the retina and cells in the thalamus of the brain respond to two pairs of colors - red-green and blue-yellow. When these cells are excited, they respond to one color of the pair; when inhibited, they respond to the complementary pair.

color blindness

the inability to distinguish two or more shades in the color spectrum. There are several types of this inability.

monochromats (color blindness)

TOTAL color blindness, their worlds look like black and white movies. This is rare and results form individuals having only rods or only one kind of functioning cone (instead of three).

dichromats (color blindness)

usually have trouble distinguishing red from green because they have just two kinds of cones. This is an inherited genetic defect, found mostly in males, that results in seeing mostly shades of green but differs in severity.

sound waves

these are the stimuli for hearing (audition), resemble ripples of different sizes. Similar to ripples on a pond, sound waves travel through space and varying heights and frequencies. Height, which is the distance from the bottom to the top of a sound wave, is called amplitude. Frequency refers to the number of sound waves that occur within 1 second.

loudness

your subjective experience of a sound's intensity.

pitch

our subjective experience of a sound being high or low, which the brain calculates from specific physical stimuli, in this case the speed or frequency of sound waves. The frequency of sound waves is measured in cycles, which refers to how many sound waves occur within 1 second.

decibel

a unit to measure loudness

140 decibels

at what decibel range does it become a risk of pain and hearing loss for us?

outer ear

consists of three structures: external ear, auditory canal, and tympanic membrane.

external ear

an oval-shaped structure that protrudes from the side of the head. The function of this structure is to pick up sound waves and send them down a long, narrow tunnel called the auditory canal.

middle ear

a bony cavity that is sealed at each end by membranes. The two membranes are connected by three small bones.

ossicles

three tiny bones that because of their shape, are referred to as the hammer, anvil, and stirrup. These three structures act like levers that greatly amplify the vibrations, which, in turn, cause the attached oval window to vibrate.

auditory canal

a long tube that funnels sound waves down its length sot hat the waves strike a thin, taut membrane - the eardrum, or tympanic membrane.

tympanic membrane

taut, thin structure commonly called the eardrum. Sound waves strike this structure and cause it to vibrate. It then passes the vibrations on to the first of three small bones to which it is attached.

cochlea

located in the inner ear, this structure has a bony coiled exterior that resembles a snail's shell. Contains the receptors for hearing, and its function is transduction - transforming vibrations into nerve impulses that are sent to the brain for processing into auditory information.

hair cells (auditory receptors)

miniature hair-shaped cells that stick up from the cochlea's bottom membrane. Bending of these cells generates miniature electrical forces that, if large enough, trigger nerve impulses.

basilar

cochlea's bottom membrane

auditory nerve

a band of fibers that carry nerve impulses (electrical signals) to the auditory cortex of the brain for processing.

primary auditory cortex

located at the top edge of the temporal lobe, this structure transforms nerve impulses into basic auditory sensations.

frequency theory

applies only to low-pitched sounds, states that the rate at which nerve impulses reach the brain determines how low the pitch of a sound is.

place theory

says that the brain determines medium - to higher - pitched sounds on the basis of the place on the basilar membrane where maximum vibration occurs.

vestibular system

located above the cochlea in the inner ear, includes three semicircular canals, resembling bony arches, which are set at different angles.

meniere's disease

results from a malfunction of the semicircular canals of the vestibular system.

vertigo

symptoms are dizziness and nausea, results from malfunction of the semicircular canals of the vestibular system.

taste

a chemical sense because the stimuli are various chemicals.

olfactory cells

the receptors for smell and are located in two 1-inch-square patches of tissue in the uppermost part of the nasal passages.

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