Special Senses

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Mechanoreceptors
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Terms in this set (52)
Mechanoreceptors
Respond to touch, pressure, vibration, stretch, and movement. Found in tendons, ligaments, joints, muscles and skin.
Thermoreceptors
Detect changes in temperature
Pain receptors (nociceptors)
Respond to tissue damage (mechanical, electrical, thermal energy)
Chemoreceptors
Stimulated by changes in the chemical concentration of substances
photoreceptors (rods and cones)
Cells that detect light.
Rods
Retinal receptors that detect black, white, and gray; necessary for peripheral and twilight vision.
(a) function in low light intensity
(b) no color discrimination
(c) high concentration around retinal periphery
Cones
Retinal receptor cells that are concentrated near the center of the retina and that function in daylight or in well-lit conditions. The cones detect fine detail and give rise to color sensations.
(a) function in high light intensity
(b) color discrimination (RGB)
(c) very high concentration in fovea centralis
(d) you move your eye to focus projection of light rays on the fovea centralis
Cornea
Transparent layer forming the front of the eye. "Window to the world"
Sclera
The white part of the eye
Aqueous humor
Fluid in the eye, found between the cornea and the lens
Canal of SchlemmDrains the aqueous humor of the eyeCiliary bodycontains involuntary muscles that control the shape (convexity) of the lens.Suspensory ligamentsAttaches the lens to the ciliary bodyIrisPigmented "diaphragm" of the eyePupilthe adjustable opening in the center of the eye through which light entersLensTransparent structure behind the pupil that changes shape to help focus images on the retina. Flattened for seeing distant objects. More rounded (convex) for nearby objects.Vitreous humorGel-like substance that helps to reinforce the eyeball and acts as a refractory media.Fovea CentralisTiny pit or depression in the retina that is the region of clearest vision due to high concentration of cones. You move your eye to project images on this area of the retina.RetinaLight-sensitive inner surface of the eye, containing the receptor rods and cones plus layers of neurons that begin the processing of visual informationChoroid coatVascular (blood supply) middle layer of the eye; heavily pigmented tunic that prevents scattering of light raysOptic diskArea of retina where the optic nerve is found that lacks photoreceptors; blind spotOrder of light passing through the eyecornea, aqueous humor, pupil, lens, vitreous humor, retinamyopianearsightedness: trouble seeing far away; light focuses behind retina (corrected with concave lens)hyperopiafarsightedness; difficulty seeing close objects; light rays are focused on a point behind the retina (corrected with convex lens)astigmatismabnormal curvature of the cornea; light rays do not converge at the same pointGlaucomaincreased pressure results in damage to the retina and optic nerve with loss of visionCataractsclouding of the lensColor blindnessA variety of disorders marked by inability to distinguish some or all colors. Most common type is red-green color blindness; x-linked, so it is more common in males.Outer earthe outermost part of the ear, consisting of the pinna and the external auditory meatusPinnathe visible part of the earexternal auditory meatusCanal leading to eardrum and middle ear (ear canal)OssiclesTiny bones of the middle ear that amplify vibrations from the tympanic membraneTympanic membraneEar drum; vibrates as sound waves hit it; transmits vibrations to the ossicles; separates outer ear from the middle earMalleus (hammer)passes vibrations from the eardrum to the anvilIncus (anvil)A tiny bone that passes vibrations from the malleus to the stapesstapes (stirrup)presses on oval window of inner ear, sets fluids in motion, excites hearing receptorsOval windowthe membrane that covers the opening between the middle ear and inner ear, transmits vibrations from the stirrup to the fluid in the inner earRound Windowlocated just below the oval window; equalizing pressure in the inner eareustachian tube (auditory tube)Opens up to the nasopharynx; equalizes pressure in the middle ear to the external environmentCochleaA coiled, bony, fluid-filled tube in the inner ear; sound waves traveling through fluid (endolymph) trigger nerve impulses (cilia) on the organ of cortiEndolymphFluid that bathes the sensory receptors of the inner earSemicircular canalsThree fluid-filled canals within the inner ear that contain specialized receptor cells that generate nerve impulses in response to movements of the head along different planes (sagittal, coronal, and transverse)VestibuleThe area between cochlea & semicircular canals. Allows us to detect changes in gravitational force and acceleration.How many varieties of cones are there?3What three colors do the cones react to?Red, Blue, GreenThe lack of color receptors results in____?Total color blindnessColor blindness occurs most commonly in___?MalesBlack and white, or dim light, vision is a function of the ___?RodsWhich two ear structures are not involved with hearing?Semicircular canals, and the VestibuleIn which state of matter must a substance be in order for us to smell it?Gaseous StateWhen are the senses of gustation and olfaction the strongest?At Birth/As an InfantOlfaction (sense of smell)The only special sense that is directly relayed to the cerebral cortex. All other special senses are relayed through the thalamus.