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
refers to the decreasing response of the sense organs, the more they are exposed to a continuous level of stimulation
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.
brain quickly changes sensations, which you're not aware of, into perceptions; meaningful sensory experiences that result after the brain combines hundreds of sensations.
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?
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.
the round opening at the from of your eye that allows light waves to pass into the eye's interior
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.
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.
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.
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.
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.
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.
a group of cells in the hypothalamus that regulates the body's circadian rhythms
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.
the intensity level of a stimulus such that a person will have a 50% chance of detecting it.
a chronic sleep disorder that is marked by excessive sleepiness, usually in the form of sleep attacks throughout the day.
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).
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).
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.
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
difficulty in assembling simple visual sensations into more complex, meaningful images.
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.
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.
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.
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.
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.
a bony cavity that is sealed at each end by membranes. The two membranes are connected by three small bones.
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.
a long tube that funnels sound waves down its length sot hat the waves strike a thin, taut membrane - the eardrum, or 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.
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.
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.
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.
says that the brain determines medium - to higher - pitched sounds on the basis of the place on the basilar membrane where maximum vibration occurs.
located above the cochlea in the inner ear, includes three semicircular canals, resembling bony arches, which are set at different angles.
symptoms are dizziness and nausea, results from malfunction of the semicircular canals of the vestibular system.