The Special SensesPhysiology 8.1 NotesVocab:- Sensory Adaptation: perception of senses decreasing until it is not aware to you- Olfaction: sense of smell- Gustation: sense of taste- Uvulva: tab of soft tissue at the back of the visible throatNotes:- Special senses are made of photoreceptors (sight), mechanoreceptors (hearing/balance),chemo-receptors (smell/taste).- Vision is the most actute sense followed by hearing.- Olfaction occurs on upper chambers of nasal passages.o Olfactory cells extend from olfactory bulb to the mucus lining in nasal cavity. o Close association of limbic system and the olfactory bulb explain the neurological connection between odors + emotion- Taste receptors are found in taste buds that line the tongue. o Distinguishes between sweet, sour, salty, bitter and umami.- Ears have 3 functional parts, outer ear, middle ear, inner ear.o Outer ear made of pinna and external auditory canalo Middle ear has the tympanic membrane (ear drum) and malleus, incus, stapes (hammer, anvil, stirrup). o Inner ear made of stapes and oval window.- Cochlea filled with liquid, has 3 compartments, with a vestibular canal that continues off oval window, tympanic canal and organ of corti.o Organ of corti converts mechanical vibrations into sensory input. o Each part of the cochlea is sensitive to different pitches. Impulses are carried to the brain and interpreted as particular pitches.o Once damaged, hair cells do not recover- Sense of static equilibrium detects up from down to make up balance.o Located within the inner ear, in utricle + saccule.o Bending of hairs inside structures sends off nerve impulses- Sense of dynamic equilibrium detects acceleration and is in 3 canals in inner ear, on x + y+ z planes. o Fluid in each tube rocks in response to acceleration.Physiology 8.2 NotesVocab:- Pupil: Hole in the center of iris- Iris: Colored portion of the front eye, regulates the pupil muscles that control amount of light entering pupil.- Retina: Inner lining of the eye that contains photoreceptors- Visual Acuity: Resolving power of the eye- Accomodation: changing of lens shape to view objects more clearly.- Vitreous Humor: gel-like fluid that holds retina in place. - Rhodospin: a chemical that responds to low levels of white light. - Rods: Detects levels of brightness, black and white- Cones: Detects color, responsible for sharpness- Fovea: blind spot at the back of the eye where optic nerve leaves- Stereoscopic Vision: depth in perception gained with two eyes- Optic Chiasm: physical crossing point of two optic nervesNotes:- Eye regulates amount of light entering the photoreceptor area and brain captures/interprets that image.- Eye has 3 layerso Sclera: dense connective tissue making white sclera and clear cornea. Connects to muscles that control the eye Lateral, medial, superior, inferior rectus muscles (up down left right) Superior + inferior pull eyes obliquely. Bathed in tears.o Choroid houses blood supply and makes sure light strikes retina only once. Visible as the iris, controlling amount of light entering pupils Bathed in aqueous humor, supplying blood.o Retina spreads out over rear of eye except at blind spot (optic nerve exit). Vitreoushumor puts pressure on retina, keeps it in place. Contains rods, cones, bipolar cells, ganglion cells.  Cones = respond to sharp light, providing color vision Rods = respond to low levels of light, vague black and white Cones are strongest at the fovea where vision is sharpest.  Rods are spread out over periphery of retina away from fovea.- Cones respond to 3 different wavelengths of light: red, green, blue.- Stereoscopic vision helps reduce risk of having blind spot as each eye covers for the other and brain fills in much of details in each view.- Once neural impulse leaves eye in fovea, it enters optic nerve, criss crosses in optic chiasma, to separate optic tract, to the temporal lobes and then visual cortex- Common visual impairments caused by inability of lens to accommodate lighto NS = eye too long, light falls in the middle of eye, in front of retina. Would need concave lens.o FS = eye too tight, light falls behind the retina. Would need convex lens.o Astigmatism = Cornea imperfectly shaped and uneven patterns of light will hit the retina. Needs carefully carved lenses. o Cataracts = scattering of light that enters the pupil, blurry imagesPhysiology 8.3 NotesVocab:- Conduction Deafness: when deafness is caused by poor conduction of vibrations from outer ear to inner ear. Can be helped by hearing aids- Nerve Deafness: When problem is in cochlear nerves or nerves to the brain.Notes:- Aging may impair special senses and chemical senses (smell/taste) declines