Term
| What type of sense is olfaction and what are receptors associated with olfaction? |
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Definition
| Chemical, "hairs" or cilia in which there are about 10-100 million in superior portion of nasal cavity. |
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Term
| What are support cells associated with olfaction? |
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Definition
| Columnar epithelium and bowman's glands. |
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Term
| What is the threshold and adaptation of olfaction like? |
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Definition
| Theshold is low, adaptation is rapid, some strong odors are completely ignored in 1 minute. |
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Term
| What is the neural pathway for olfaction? |
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Definition
| Cranial nerve I to olfactory bulb to olfactory tract to limbic system/hypothalamus to cerebral cortex, only sensory system that does not synapse in thalamus before sending signals to cerebrum. |
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Term
| What type of sense and what receptors are associated with gustation? |
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Definition
| Chemical (closely related to smell), gustatory cells with single long cilia projection (50 per taste bud and 10,000 buds total). |
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Term
| What are the 5 primary tastes and the highest and lowest threshold of those tastes and quickness of adaptation? |
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Definition
1. Sour
2. Sweet
3. Bitter
4. Salt
5. Umami
Adaptation is within 1-5 mins, bitter has lowest threshold, salt and sweet have highest threshold. |
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Term
| What is the neural pathway for gustation? |
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Definition
| Cranial nerves VII/IX/X to the medulla to the limbic system/hypothalamus/thalamus, then thalamus to cerebral cortex. |
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Term
| What is another name for eyelids and what are their functions? |
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Definition
| Palpebrae, shade during sleep, protect from excessive light/foreign objects, spread lubricant over eyeball. |
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Term
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Definition
| Mucous membrane that covers inner surface of eyelids and surface of eyeball up to cornea, conjuctivitis is when the cappilaries dilate due to infection or irritation. |
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Term
| Describe functions of the eyelashes and eyebrows. |
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Definition
| Eyelashes protect from foreign objects/perspiration/direct sunlight rays, eyebrows protect from foreign objects/perspiration/direct sunlight rays. |
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Term
| What is the choroid of the eye? |
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Definition
| Most posterior portion, most of inner surface of sclera, provides nutrients to posterior part of retina, highly vascular. |
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Term
| What is the ciliary body of the eye? |
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Definition
| Extends from anterior edge of retina to junction of cornea and sclera, contains: ciliary processes which secrete aqueous humor, suspensory ligaments which attach to lens, and ciliary muscles which are circular smooth muscle that alters shape of lens. |
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Term
| What is the iris of the eye? |
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Definition
| Colored portion of eyeball, consists of radial and circular smooth muscle, regulates pupil size. |
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Term
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Definition
| Many different genes contribute to color, no discrete colors of human eyes, spectrum of colors between blue and brown, iris in a single person has many different colors in it, color results from combination of yellow and black. |
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Term
| What are the pigment epithelium of the retina? |
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Definition
| Lies between choroid and neural portion, melanin absors light and prevents reflection/scattering of light within eyeball. |
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Term
| What is the lacrimal apparatus of the ye? |
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Definition
| Produces and drains tears, duct which empties onto conjuctiva, collects in lacrimal puncta, drains into nasal cavity. |
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Term
| What is the diamater of the eyeball and the 3 layers? |
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Definition
Diamater: 1 inch
Fibrous tunic: outer layer - avascular, includes cornea/sclera
Vascular tunic: middle layer, includes choroid/ciliary body/iris
Nervous tunic: inner layer, includes retina |
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Term
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Definition
| Transparent covering of iris, helps refract light. |
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Term
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Definition
| White of the eye, dense connective tissue, gives shape and rigidity to eyeball. |
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Term
| What is the neural portion of the retina, including the 3 layers? |
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Definition
Outgrowth from brain, three layers:
1. Photoreceptor layer (inner)
2. Bipolar cell layer (middle)
3. Ganglion cell layer (outer)
Light passes through ganglion and bipolar layers to reach photoreceptors, blind spot is optic disc where optic nerve exits eyeball, macula lutea is central part of posterior retina, central fovea is in center of macula lutea. |
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Term
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Definition
| Posterior to pupil, avascular, made of proteins called crystallins and enclosed by clear connective tissue, normally transparent, held in place by suspensory ligaments. |
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Term
| What is the anterior cavity of the interior of the eyeball like? |
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Definition
| Contains anterior chamber and posterior chamber, filled with aqueous humar, replaced every 90 mins, produces introcular pressure but if too much can lead to glaucoma. |
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Term
| What is the posterior cavity of the interior of the eyeball like? |
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Definition
| Between lens and retina, contains vitreous body which is jellylike and pushes retina against choroid/maintains eyeball shape, not continually replaced, contains phagocytic cells which remove debris to clear vision. |
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Term
| What are the 3 components of image formation? |
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Definition
| Refraction, accomodation, constriction. |
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Term
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Definition
| Bending of light rays as they enter eye, 75% corneal refraction and 25% lens, image inverted on retina so left goes right and vice versa, bent rays focus on central fovea. |
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Term
| What is accomodation including the near point? |
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Definition
| Increased curve on back side of lens to focus on near objects, less tension on suspensory ligmanets, near point is minimum distance at which eye can focus. |
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Term
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Definition
| Narrowing of the pupil eliminates peripheral rays for finer focus, occurs simultaneously with accommodation and also in brighter light. |
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Term
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Definition
| Medial movement of both eyes to focus on same object, results in binocular vision for better depth perception. |
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Term
| What are the 2 photoreceptors? |
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Definition
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Term
| Describe the structure of photoreceptors. |
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Definition
Outer segment: transduction of light energy into receptor potential occurs, photopigments, folded plasma membrane or discs
Inner segment: cell body, axon, mitochondria, golgi complex |
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Term
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Definition
| Colored pigments that absorb light, rhodopsin absorbed by rods, blue/green/red absorbed by cones, all photopigments contain opsin (glycoprotein) and retinal (a light-absorbing protein) |
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Term
| What is the 4 step process of the photopigment response to light? |
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Definition
1. Cis (bent) goes to trans (straight) retinal when hit by light which produces unstable chemicals
2. 1 min later trans-retinal separates from opsin
3. Retinal isomerase converts trans-retinal to cis-retinal
4. Cis-retinal binds to opsin |
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Term
| Describe th two adaptations from light to dark and from dark to light. |
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Definition
Dark to light: fast
Light to dark: slow |
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Term
| What are a couple photoreceptor abnormalities? |
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Definition
Color blindness: cone defects
Nyctalopia: poor night vision |
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Term
| What are the functions of the rods in retinal processing? |
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Definition
| Low light threshold, very sensitive, black/white, slow regeneration process, contribute little to daytime vision, affects night vision. |
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Term
| What are the functions of cones in retinal processing? |
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Definition
| High light threshold, less sensitive, color, main source of vision, cones regenerate faster than rods. |
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Term
| What are the functions of neurotransmitters in retinal processing? |
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Definition
| Glutamic acid, inhibitory neurotransmitter, triggers IPSPs, hyperpolarization of bipolar cells, inhibit sending signal to ganglion cells. |
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Term
| What are the functions of horizontal cells in retinal processing? |
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Definition
| Transmit lateral inhibitory siganls from photoreceptors to bipolar cells located laterally to rods/cones, enhances contrast and color discrimination, located in bipolar cell layer. |
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Term
| What are the functions of excited bipolar cells in retinal processing? |
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Definition
| Light causes Na+ channels to close, decrease glutamic acid release from rods/cones to bipolar cells, lose IPSP which means an AP is generated which induces graded potentials in bipolar and horizontal cells, thus light excites bipolar cells by turning off the release of inhibitory neurotransmitter. |
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Term
| What are the functions of amacrine cells in retinal processing? |
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Definition
| Excited by bipolar cells then synapse with ganglion cells, signal change in light intensity, modify ganglion cell responses to bipolar cell stimuli, located in bipolar cell layer. |
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Term
| What are the functions of ganglion cells in retinal processing? |
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Definition
| Become excited by signals from bipolar or amacrine cells, initiate nerve impulse in optic nerve. |
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Term
| What is the neural pathway for vision and what types of neurons are involved? |
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Definition
Sensory axons involved, optic nerve goes to optic chiasm then goes to thalamus then goes to visual cortex, incomplete decussation, 3 areas in cortex analyze vision:
1. Shape
2. Color
3. Movement/location/spatial arrangement |
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Term
| How much faster does transduction occur in sound than light? |
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Definition
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Term
| Describe the parts and structure of the external ear. |
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Definition
| Auricle is a helix/lobule, external auditory canal is 1" long/curved/has some hairs/ceruminous glands which secrete earwax, eardrum here. |
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Term
| Describe the parts and structure of the middle ear. |
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Definition
Air-filled cavity, bound by eardrum and oval round windows 3 auditory ossicles with synovial joints:
1. Malleus (hammer)
2. Incus (anvil)
3. Stapes (stirrup)
Eustachian tube helps with pressure equilibrium and is route for pathogens to travel from nose/throat to middle ear. |
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Term
| Describe the parts and structure of the inner ear. |
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Definition
Semicircular canals: equilibrium, 3 oriented at 90 degree angles
Vestibule: equilibrium, contains utricule and saccule
Cochlea: hearing
Perilymph: surrounds membranous labyrinth |
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Term
| Describe the physiology of hearing in relation to the physics of sound. |
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Definition
| Audible spectrum of 20 - 20,000 Hz, membranes closest to oval window respond to high frequencies, those closer to round window respond to low frequencies, 90 dB or higher is dangerous for hearing, 140 dB is painful. |
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Term
| What is the order in which sound goes through the ear? |
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Definition
| External auditory canal to the tympanic membrane to the middle ear ossicles to the oval window to the round window to the vestibular membrane to the basilar membrane to the tectorial membrane which bends hair cells which activates cochlear nerve impulses. |
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Term
| What is the neural pathway for hearing? |
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Definition
| First order neurons in cranial nerve VIII go to medulla then go to pons then go to midbrain then go to thalamus then go to cortex. |
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Term
| What are the two kinds of equilibrium in hearing and what parts are involved? |
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Definition
| Static and dynamic, vestibular apparatus is involved, vestibular apparatus components include otolithic organs and semicircular ducts. |
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Term
| What are the functions, components, physiology, and nerve of the otolithic organs? |
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Definition
| Functions include primary static equilibrium/dynamic equilibrium/position of head/maintain posture and balance, components include saccule and utricle, physiology includes otoliths in otolithic membrane interacting with hair cells, nerve is cranial nerve VIII |
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Term
| What are the functions, components, physiology, and nerve of the semicircular ducts? |
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Definition
| Functions include dynamic equilibrium, components include ampullae with elevations/cupula/hair cells, physiology includes endolymph flow moving from cupula which bends hairs and creates potential, nerve is cranial nerve VIII. |
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Term
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Definition
| High intraocular pressure due to buildup of aqueous humor, most common U.S. cause of blindness, destruction of retina, painless so much damage happens before detected, risk factors include age/ethnicity/genetics/previouse eye injuries and disease. |
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Term
| Describe the 2 main ways deafness occurs. |
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Definition
Sensorineural: damage to cochlear hair cells or damage to cranial nerve VIII, cause include atherosclerosis/aspirin/streptomycin/loud noise, treated with cochlear implants
Conduction: impairment of external or middle ear mechanisms for transmitting sounds to inner ear, otosclerosis, impacted cerumen, eardrum injury, aging. |
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Term
| What is meniere's disease? |
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Definition
| Too much endolumph, enlarged membranous labyrinth, intermittent hearing loss, roaring tinnitis, vertigo, complete hearing loss over period of years. |
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Term
| What is senile macular degeneration? |
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Definition
| Leading cause of blindness for people over 75 years of age, destruction of macular region of retina, lose acute vision but reatin peripheral vision, some not treatable but others can with laser destruction of blood vessels, smoking is a risk. |
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Term
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Definition
| Acute middle ear infeciton, bacteria from nose and throat, pain/malaise/fever/red swollen eardrum, may rupture, buildup of pus in middle ear, more in children. |
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Term
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Definition
| Accelerations in different directions or loss of visual contact with horizon, confilcts of visual clues and equilibrium, fear makes it worse, dizziness/fatigue/nausea/vomiting. |
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Term
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Definition
|
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Term
|
Definition
|
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Term
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Definition
| Loss of vision in otherwise normal eye. |
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Term
|
Definition
| Loss or impairment of sense of smell. |
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Term
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Definition
|
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Term
|
Definition
| Pinkeye, redness of conjuctiva. |
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Term
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Definition
| Corneal inflammation or infection. |
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Term
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Definition
| Rapid jerky eye movements. |
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Term
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Definition
|
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Term
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Definition
| Drooping of upper eyelid. |
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Term
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Definition
| Most common childhood intraocular cancer. |
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Term
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Definition
| Area of diminished vision within the field of vision. |
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Term
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Definition
| Visual disorder where eyes are misaligned and point in different directions. |
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Term
|
Definition
|
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Term
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Definition
| Caused by chlamydia, leading cause of blindness worldwide. |
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Term
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Definition
| Disordered state in which the individual or the individual's surroundings seem to whirl dizzily. |
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