Sensation (2024 CED)

absolute threshold

absolute threshold

The minimum stimulation needed to detect a particular stimulus 50% of the time.

accommodation

The process by which the focus of the eye is changed to allow near or distant objects to form sharp images on the retina.

afterimages

A visual image that persists after a stimulus is removed.

amplitude

The height of a wave as measured from the highest point on the wave (peak or crest) to the lowest point on the wave (trough).

bitter

the unpleasant taste evoked by foods like coffee, spinach, and brussels sprouts; natural selection may contribute to a predisposition to find these tastes unpleasant, especially during early childhood, as bitter-tasting substances in the natural environment are often toxic

blindspot

The point at which the optic nerve leaves the eye, creating an area in which no visual information can be detected because no receptor cells are located there.

conduction deafness

Hearing loss caused by damage to the mechanical system that conducts sound waves to the cochlea.

cones

Retinal receptor cells that are concentrated near the center of the retina and that function in daylight and in well-lit conditions. The cones detect fine detail and give rise to color sensations.

dichromatism

Partial color blindness in which the eye contains only two types of cone photopigment instead of the typical three: Red-green color blindness is the most common, whereas the blue-green variety is relatively rare.

farsightedness

is a refractive error due to an abnormally short eyeball, which causes the image of close objects to be blurred because the focal point of one or both eyes lies behind, rather than on, the retina

frequency theory

The rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone, thus enabling us to sense its pitch.

ganglion cells

The last layer of photoreceptors within the retina that sends signals to the brain resulting from visual stimulation.

gate control theory

Spinal cord contains a neurological "gate" that blocks pain signals air allows them to pass on to the brain. The "gate" is opened by the activity of pain signals traveling up small nerve fibers and is closed by activity in larger fibers or by information coming from the brain.

gustation

The sense of taste. Taste is at the threshold between the external (chemical) and internal (biochemical) worlds; it serves an organism's nutritional needs and protects it from poisons.

just-noticeable difference

The minimum distinction between two stimuli required for detection 50% of the time.

kinesthesis

Also known as proprioception, this is the sense of the location of body parts in relation to the ground and each other.

lens

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

loudness

the subjective magnitude of sound. It is determined primarily by intensity but is also affected by other physical properties, such as frequency, spectral configuration, and duration

medium tasters

average ability tasters

monochromatism

a partial color blindness in which the eye contains only one type of cone photopigment instead of the typical three: Everything appears in various shades of a single color

nearsightedness

The retinal image is blurred because the focal point of one or both eyes lies in front of, rather than on, the retina.; this allows you to see what is near you, but struggles with items far away

nontasters

someone who has less taste perception; like hot spicy foods, and usually require more seasoning to make it taste good. This is true except for salt; have a clear preference for high-fat, sweeter foods

oleogustus

the unique taste of fat, recently identified as separate from other distinct tastes

olfactory system

The sense of smell, involving stimulation of receptor cells in the olfactory epithelium (located in the nasal passages) by airborne volatile substances called odorants.

opponent-process theory

Opposing retinal processes (red-green, yellow-blue, white-black) enable color vision.

phantom limb

The feeling that an amputated limb is still present, often manifested as a tingling or, occasionally, painful sensation in the area of the missing limb.

pheromones

Olfactory chemical messages that are released outside the body by members of a species and that influences the behavior of other members of the species. For, example, it may serve to attract a mate or to act as an alarm.

photoreceptors

Visual receptors in the eye, specifically rods and cones.

pitch

A tone's experienced highness or lowness; depends on frequency.

pitch perception

The ability to distinguish between tones played at differing frequencies.

place theory

Links the pitch we hear with the place where the cochlea's membrane is stimulated

prosopagnosia

Inability to recognize familiar faces.

retina

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

rods

Retinal receptors that detect black, white, and gray; necessary of peripheral vision and twilight vision.

salty

the unique taste evoked by sodium chloride or lithium chloride, or other sodium and lithium salts; sodium cannot be produced in the body, even though it's essential for body processes, and therefore must be ingested

semicircular canals

A set of three looped tubular channels in the inner ear that detect movements of the head and provide the sense of dynamic equilibrium that is essential for maintaining balance.

sensation

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

sensorineural deafness

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

sensory adaptation

Diminished sensitivity as a consequence of constant stimulation.

sensory interaction

The principle that one sense may influence another, as when the smell of food influences its taste.

sound localization

The ability to identify the position and changes in position of sound sources based on acoustic information.

sour

the taste elicited by acid; acids are involved in many physiological processes and also characterize unripe or spoiled foods; thus, their detection is essential for an organism's homeostasis and food selection.

supertaster

An individual whose perception of taste sensations is the most intense; about 25% of the population. These individuals are more sensitive to bitter and spicy tastes; they are so sensitive to bitter they tend to be very picky eaters and dislike many foods

sweet

the pleasurable taste associated with sugars, an immediate source of energy

synesthesia

When one kind of sensory stimulus evokes the subjective experience of another.

taste receptors

Proteins that recognize taste stimuli

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 - all senses but smell are processed here.

transduction

Conversion of one form of energy into another - transferring stimulus energies into neural impulses our brains can interpret.

"

The theory that the retina contains three different color receptors - one most sensitive to red, green, and blue - which, when stimulated in combination, can produce the perception of any color.

umami

denoting the taste of foods rich in protein (e.g., meats, fish, some vegetables, cheeses), as represented by the taste of monosodium glutamate, which is used primarily to enhance other flavors. Umami is sometimes described as "savory." [Japanese, "delicious"]

vestibular sense

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

visual nerve

Carries neural impulses from the eye to the brain.

volley theory

This theory states that groups of neurons of the auditory system respond to a sound by firing action potentials slightly out of phase with one another so that when combined, a greater frequency of sound can be encoded and sent to the brain to be analyzed.

warm/cold receptors

thermoreceptors; recetpors on our skin that are either sensitive to warmth or to cold; Cold receptors are free nerve endings with thin myelinated fibers, whereas the warm receptors are free nerve endings with unmyelinated axons with low conduction speeds

wavelength

The distance between two corresponding parts of a wave; determines color within vision and pitch within sounds.

Weber's law

The principle that, to be perceived as different, two stimuli must differ by a constant percentage (rather than a constant amount).

blindsight

A condition in which people who are blind have some spared visual capacities in the absence of any visual awareness.

Red Waves of Light

These are long waves of light.

Green Waves of Light

These are medium waves of light.

fovea

The central focal point in the retina, around which the eye's cones cluster.