Special Senses

35. Describe the cyclical pathway of photopigment bleaching and regeneration.

(dark) 1. 11-cis-retinal combines with opsin to form rhodopsin (light) 2. light absorption by rhodopsin triggers retinal to change shape into all-trans-retinal and release from opsin (dark) 3. all-trans-retinal is converted back into 11-cis-retinal cycle repeats

61. Identify the two muscles of the middle ear and describe their function.

-tensor tympani: arises from the wall of the pharyngotympanic tube and inserts on the malleus -stapedius: runs from posterior wall of the middle ear to the stapes. when loud sounds assault the ears the muscles contract reflexively to limit the ossicles' vibration and minimize damage to the hearing receptors

2. What type of tissue comprises the conjunctiva? Distinguish between the palpebral conjunctiva and bulbar conjunctiva. Is the cornea covered by conjunctiva?

-the conjunctiva is a mucus membrane -the palpebral conjunctiva lines the eyelids -the bulbar conjunctiva folds over the anterior surface of the eyeball (covering only the white of the eye not the cornea)

10. Describe the structure of the iris. How does the iris modify the amount of light that enters the posterior segment of the eye?

The iris is made up of two muscles, the sphincter pupillae and the dilator pupillae. in close vision/bright light the sphincter pupillae contracts, causing the pupil to constrict. in distant vision/dim light, the dilator pupillae contracts causing the pupil to dilate (allowing more light in).

40. Continue to follow the path of the visual stimulus as it is transduced to an electrical impulse by the photoreceptors of the retina, and carried from the eye to the brain (see Fig 15.19 in your textbook and the similar illustration in the lecture ppt file)

eye to optic chiamsa to hypothalamus and fans out to visual cortex and occipital lobe

45. Are olfactory receptors considered to be rapid or slow adapting?

fast

41. What occurs in the optic chiasm (aka optic chiasma)?

fibers from the medial aspect of each eye cross over to the opposite side and then continue on via the optic tract

50. Identify and describe the function of the cell types of a taste bud.

gustatory epithelial cells: receptor cells for taste; long microvilli (gustatory hairs) project from the tips of the gustatory epithelial cells and extend through a taste pore to the surface of the epithelium where they are bathed in saliva; at least three kinds of gustatory epithelial cells basal epithelial cells: act as stem cells, dividing and differentiating into new gustatory epithelial cells

44. Identify the specific site of olfactory transduction.

olfactory cilia membrane

33. Name and describe the two parts of all photopigments.

opsin retinal

80. How does the otolithic membrane contribute to stimulation of the hair cells of the macula?

otoliths in the membrane increase the membrane's weight, increasing its inertia (resistance to changes in motion)

31. In which part of the photoreceptor cell are the photopigments located?

outer segment

25. What is the functional significance of the near point of vision? Describe the typical age- related changes in the near point of vision.

the near point of vision is the closest point on which we can focus clearly (the maximum bulge the lens an achieve). in the emmetropic adult eye it is about 4in away (closer in children and then recedes with age)

12. Identify and locate (with respect to each other and to the eyeball as a whole) the two layers of the retina.

the retina is composed of an outer pigmented layer and an inner neural layer. the outer pigmented layer is a single cell thick and is next to the choroid, extending anteriorly to cover the ciliary body and the posterior face of the iris the inner neural layer extends anteriorly to the posterior margin of the ciliary body

13. What are the primary functions of the pigmented layer with respect to clear vision?

-absorb light and prevent it from scattering in the eye -act as phagocytes participating in photoreceptor cell renewal -store vitamin A needed by photoreceptors

28. Reading for long periods of time causes eye strain (or eye fatigue). There are 3 mechanisms that contribute to the fatigue. What are they?

-accommodation of the lenses -constriction of the pupils -convergence of the eyeballs

27. Describe how the accommodation pupillary reflex and eyeball convergence contribute to clear and focused near vision.

-accommodation pupillary reflex is when the sphincter pupillae muscles enhance accommodation by reducing the size of the pupil. it prevents the most divergent light rays from entering the eye, which would pass through the extreme edge of the lens and wouldn't focus properly, causing blurred vision -convergence is the medial rotation of the eyeballs by the medial rectus muscle so that each is directed toward the object being viewed. the closer the object the greater the degree of convergence required (cross-eyed). keeps the object focused on the retinal foveae

47. Trace the path of an olfactory impulse from the upper nasal cavity to the synapse with a second-order neuron in the glomerulus of the olfactory bulb, to the olfactory cortex and subcortical areas.

-axons of the olfactory neurons form the olfactory nerves hat synapse in the olfactory bulbs -filaments of olfactory nerves synapse with mitral cells (2nd order sensory neurons) in glomeruli (each glomerulus represents a single aspect of an odor; different odors activate different subsets of glomeruli) -when mitral cells are activated impulses flow from olfactory bulbs via olfactory tracts to piriform lobe of olfactory cortex -from olfactory cortex can either go along pathway to frontal lobe where smells are consciously interpreted and identified, or to hypothalamus/amygdaloid body where emotional responses to odors are elicited

55. Which cranial nerves are involved with gustation? What is the location of the taste buds associated with each of the CNs?

-facial nerve (CN VII): transmits impulses from taste receptors in anterior 2/3 of tongue -lingual branch of glossopharyngeal nerve (CN IX): serves posterior 1/3 of tongue and pharynx -vagus nerve (CN X): impulses from epiglottis and lower pharynx

4. Name the three layers of the wall of the eye from outermost to innermost

-fibrous layer -vascular layer -inner layer (retina)

24. Describe how the lens shape changes during accommodation for near vision. What is the role of the ciliary muscle and ciliary zonule in the lens shape change during accommodation for near vision? How do the ciliary muscle and ciliary zonule function to flatten the lens for far vision?

-for near vision the ciliary muscle contracts causing the ciliary zonule to loosen, which allows the lens to bulge -for far vision the ciliary muscle relaxes causing the ciliary zonule to tighten, which flattens the lens

17. What region of the retina produces the sharpest vision? Explain the two reasons why is acuity so high in this region?

-fovea centralis of the macula lutea -the retinal structures next to the vitreous humor are displaced to the sides, allowing light to pass almost directly to the photoreceptors (instead of through several retinal layers) -the fovea contains only cones

72. How are frequency and intensity of sound vibrations encoded by the spiral organ?

-frequency causes vibration in different parts of the basilar membrane -intensity of sound is interpreted by the degree of hair cell distortion

48. Identify and describe the types of papillae found on the surface of the tongue.

-fungiform papillae: scattered over entire tongue but only have 1-5 tastebuds each -vallate papillae: largest and least numerous papillae but have many taste buds. 8-12 valuate papillae form inverted V at back of tongue -foliate papillae: located laterally on tongue; contain many taste buds during childhood but fewer with age

84. Identify and describe the function of the hair cells and cupula of the cristae.

-hair cells and supporting cells -essentially the same function as those of the cochlea/maculae -ampullary cupula is delicate, loosely organized network of gelatinous strands that radiate outward to connect the "hairs" of each hair

56. Trace the gustatory pathway from taste buds to the gustatory cortex and subcortical areas

-impulses from taste buds are transmitted via the glossopharyngeal, facial, or vagus nerve -they all synapse with a second order motor neuron at the solitary nucleus in the medulla oblongata -from there the signal is transported into the thalamus where it synapses with a third order motor neuron -the impulse is then relayed to the gustatory cortex

32. Compare and contrast (structure and function) rods and cones.

-in rods the outer segment is slender and the inner segment connects to the cell body by outer fiber. discs are discontinuous (stacked like pennies inside plasma membrane). rods are very sensitive making them best suited for night and peripheral vision. single visual pigment --> gray tones. participate in converging pathways; effects are summated and considered collectively leading to fuzzy vision. more numerous than cones. located mostly in peripheral retina. -cones have a short conical outer segment and the inner segment directly joins cell body. disc membranes are continuous with plasma membrane; interiors of cone discs are continuous with extracellular space. cones need bright light for activation but react more rapidly. contain three different pigments to portray colored view. each cone has own pathway to ganglion cell --> detailed high acuity views. located mostly in central retina.

3. Name the extrinsic eye muscles, describe their innervation, and tell what movement each produces.

-lateral rectus: moves eye laterally -medial rectus: moves eye medially -superior rectus: elevates eye and turns it medially -inferior rectus: depresses eye and turns it medially -inferior oblique: elevates eye and turns it laterally -superior oblique: depresses eye and turns it laterally

58. What structures create the borders of the middle ear?

-laterally: eardrum -medially: boney wall with oval + round windows -superiorly: forms epitympanic recess -anterior wall: next to internal carotid artery and contains opening of auditory tube

62. What two regions are connected by the auditory tube? How does the auditory tube contribute to hearing?

-links middle ear cavity with nasopharynx -normally the tube is flattened but it opens briefly when swallowing or yawning to equalize pressure in the middle ear cavity with external air pressure. the eardrum vibrates freely only if the pressure on both of its surfaces is the same

26. Describe the abnormality in refraction which characterizes each of the following conditions: myopia; hyperopia; astigmatism.

-myopia: nearsightedness; eyeball is too long, so focal point for light is in front of the retina. correct w concave lens which moves focal point further back -hyperopia: farsightedness; eyeball is too short so focal point is in front of retina. correct w convex lens that moves focal point forward -astigmatism: unequal curvatures in different parts of the cornea or lens

8. What are the primary functions of the choroid?

-nourish all layers of the eye -absorb light and prevent it from reflecting with the eye and causing visual confusion

42. Identify and describe the function of the three distinct cell types of the olfactory epithelium

-olfactory sensory neurons: bipolar neurons with a thin apical dendrite that terminates in a knob that has several long cilia. the cilia increase the receptive surface area -supporting cells: columnar supporting cells that make up the bulk of the epithelial membrane, contain yellow-brown -olfactory stem cells: base of epithelium

34. Which of the parts described above (#33) is the light-absorbing part of the photopigment? which part differs from one type of photopigment to another?

-opsin differs between rod and cone and between cones -retinal is light absorbing

57. What structures constitute the outer ear? the middle ear? the inner ear?

-outer ear: auricle (pinna), external acoustic meatus -middle ear: auditory ossicles (malleus, stapes, incus), eardrum, oval window, round window, auditory tube -internal ear: bony labyrinth, membranous labyrinth

30. Describe the general structure of photoreceptor cells.

-outer segment: receptive regions of rods/cones immersed in the pigmented layer of the retina -outer segment joined to inner segment by a connecting cilium -inner segment connects to the cell body -cell body is continuous with a fiber that has synaptic terminals

65. Where is perilymph located? endolymph?

-perilymph fills the bony labyrinth and the membranous labyrinth is suspended in the surrounding perilymph -endolymph is contained within the membranous labyrinth

69. When frequency varies, we perceive changes in ____________. Changes in amplitude are interpreted as changes in _______________.

-pitch -loudness

53. Which of the primary tastes is associated with a transduction process involving Na+ inflow across the membrane of the gustatory hair? Which is mediated by H+? Which apparently utilize a G protein-mediated mechanism?

-salty taste is due to an influx of Na+ through Na+ channels which directly depolarizes gustatory epithelial cells -sour taste is mediated by H+ which acts intracellularly to open channels that allow other cations to enter -bitter, sweet, and umami use a G protein mediated mechanism, where activation leads to the release of Ca2+ from intracellular stores, causing cation channels in the plasma membrane to open and depolarizing the cell

66. Describe the internal structure of the cochlea. Note the location of cochlear structures with respect to the oval and round windows. Where in the cochlea is endolymph located? perilymph?

-scala vestibuli: part of the bony labyrinth continuous with the vestibule and beginning at the oval window; contains perilymph -scala media: part of membranous labyrinth; is the cochlear duct itself; contains endolymph -scala tympani: part of the bony labyrinth; terminates at round window; contains perilymph

7. Identify and describe the three parts of the vascular layer of the eye.

-the choroid is a blood vessel rich, dark brown membrane that nourishes all eye layers. the brown pigment helps absorb light and prevent it from reflecting within the eye. -the ciliary body is a thickened ring of tissue that encircles the lens and is composed of the ciliary muscles, ciliary processes, and ciliary zonule -the iris is the colored part of the eye. the pupil allows light to enter the eye, the iris is made of up two smooth muscle layers with elastic fibers

15. Which of the cell layers (#14) tranduces visible light energy? which cells generate an action potential?

-the ganglion cells generate action potential -photoreceptors tranduce visible light

64. Identify and locate (with respect to each other and to the bony labyrinth) the various parts of the membranous labyrinth.

-the membranous labyrinth is a continuous series of membranous save and ducts contained within the bony labyrinth vestibule -saccule: continuous with membranous labyrinth extending anteriorly into the cochlea -utricle: continuous with semicircular ducts extending into semicircular canals posteriorly both house equilibrium receptor regions called maculae that respond to the pull of gravity and report on changes of head position semicircular canal -semicircular duct: communications with utricle anteriorly -ampulla: enlargement on the end of each semicircular duct that houses an equilibrium receptor region called a crest ampullaris; responds to rotational movements of the head cochlea -cochlear duct: houses receptor organ of hearing (spinal organ/organ of Corti)

5. Describe the general structure and function of each of the layers named above (#4).

-the outermost fibrous layer is composed of dense avascular CT. it is composed of the sclera and the cornea -the vascular layer is the middle layer of the eyeball and is composed of the choroid, ciliary body, and iris -the inner layer is the retina, which is composed of the neural and pigmented layer; it is the light detecting part of the eye

81. Describe the process through which head movement creates a receptor potential (i.e., a depolarization) or repolarization of the macular hair cells.

-tilting the head forward makes the hairs bend toward the kinocilium -the hair cell depolarizes -nerve fiber is excited -increase in APs in vestibular nerve -tilting the head back makes the hairs bend away from the kinocilium -the hair cell hyperpolarizes -nerve fiber is inhibited -decrease in Ads in vestibular nerve

63. Identify and locate with respect to each other the three unique regions of the bony labyrinth.

-vestibule: lies posterior to the cochlea, anterior to the semicircular canals, flanks middle ear medially. in its lateral wall is the oval window. -semicircular canals: lie posterior and lateral to the vestibule. the cavities of the canals project from the posterior aspect of the vestibule, anteriorly, posteriorly, and laterally. -cochlea: the cochlea extends from the anterior part of the vestibule and coils around a bony pillar called the modulus.

29. Identify how you would assess each of the following and why: -visual acuity -observation of the retina, arteries and veins -accommodation -color blindness -convergence

-visual acuity: snellen chart, "E" chart, near vision chart -retina etc: use opthalmoscope -accommodation: shining light into each eye and watching pupil constrict -color blindness: -convergence: have patient follow finger/object as you bring it toward their nose

73. Describe the auditory pathway from the sensory afferents at the base of the hair cells to the auditory cortex and subcortical areas.

1. action potentials generated in the cochlea pass through the spiral ganglion and along the afferent fibers of the cochlear nerve to the cochlear nuclei of the medulla 2. neurons project to the superior olivary nucleus at the junction of the medulla and pons 3. from here axons ascent in the lateral lemniscus tract to the inferior colliculus 4. the inferior colliculus projects to the medial geniculate nucleus of the thalamus 5. axons of the thalamic neurons project to the primary auditory cortex (provides conscious awareness of sound)

54. Rank the activation thresholds for the primary tastes

1. bitter 2. sour 3. salty 4. sweet 5. umami

21. Identify in order the structures or materials through which light passes as it moves from the air to the retina.

1. cornea 2. aqueous humor 3. lens 4. vitreous. humor 5. neural layer of retina 6. photoreceptors of pigmented layer

46. Describe the process of transduction in an olfactory receptor cell.

1. odorant binds to a receptor protein 2. GDP binds to receptor and is transformed to GTP 3. GTP activates adenylate cyclase 4. adenylate cyclase converts ATP to cAMP 5. cAMP binds to voltage gated ion channel and opens it, allowing influx of Ca2+ and Na+ causing depolarization

71. Describe the events involved in transducing sound vibrations, beginning with a sound wave passing through the external auditory canal.

1. sound waves entering the external acoustic meatus strike the tympanic membrane and it vibrates 2. the motion of the tympanic membrane is amplified and transferred to the oval window by the ossicle lever system 3. as the stapes rocks back and forth against the oval window it sets the perilymph in the Scala vestibuli into a similar motion. pressure wave travels through the perilymph from basal end toward helicotrema 4. sound waves of a low frequency (below 20Hz) create pressure waves that take the complete route through the cochlea; sound waves with frequencies that are high enough to create pressure waves are transmitted through the cochlear duct into the perilymph of the scala tympani. it vibrates the basilar membrane causing the hair cells to active and APs are sent to the brain

76. What type of tuning fork is best for assessing a patient's ears? Explain your answer.

512Hz bc it's mid speaking so it's the one we would hear the most

37. What is the "dark current"? In darkness, what is the membrane potential of photoreceptor cells? What happens to its membrane potential when a photoreceptor cell is exposed to light?

a continuous influx of Na+ ions into the outer segment; depolarized; light triggers pigment breakdown which results in hyperpolarization of the cell (Na+ channels are closed) and inhibition of NT release (Ca2+ channels close)

83. In what part of the semicircular ducts are the cristae located?

ampulla

19. Where is aqueous humor located and what is its function?

aqueous humor is a clear fluid located in the anterior segment of the eye. it forms and drains continually, helping to maintain a constant intraocular pressure which helps support the eyeball internally. it also supplies nutrients and oxygen to the lens and cornea and carries away metabolic wastes.

43. Olfactory receptor cells (i.e., olfactory sensory neurons) are an example of what type of neuron?

bipolar

74. Name and describe the difference between the two types of hearing loss/deafness?

conductive (A loss of auditory sensitivity due to deformation, malfunction, or obstruction of the outer or middle ear), sensorineural (Results from the absence, malformation of, or damage to the structures of the inner ear; most notably to the hair cells within the cochlea)

1. Identify the general function of the following accessory structures of the eye: eyelids, eyebrows, and eyelashes; conjunctiva; lacrimal apparatus (lacrimal glands, lacrimal canals & ducts); extrinsic eye muscles.

eyelids: thin, skin covered folds supported internally by connective tissue sheets called tarsal plates. eyelid muscles are activated reflexively to cause blinking every 3-7 seconds and protect the eye from foreign objects eyebrows: short, coarse hairs that overlie the supraorbital margins of the skull & help shade the eyes from sunlight and prevent perspiration trickling down the forehead from reaching the eyes eyelashes: richly innervated follicles; anything that touches the eyelash triggers reflex blinking conjunctiva: transparent mucous membrane that lines the eyelids and folds back over the anterior surface of the eyeball; produces lubricating mucus that prevents the eye from drying out lacrimal gland: lies in the orbit above the lateral end of the eye + visible through the conjunctiva when lid is everted; continuously releases lacrimal secretion (tears) into superior part of conjunctival sac. blinking spreads the tears downward and across the eyeball and they enter the lacrimal canaliculi and then drain into the lacrimal sac nasolacrimal duct: carries tears from lacrimal sac to the nasal cavity at the inferior nasal meatus extrinsic eye muscles: control movement of the eye -- moves eye laterally, medially, elevates eye and turns it laterally, medially, depresses eye and turns it laterally, medially

68. Two important properties of sound are frequency and amplitude. What unit of measure is used to express sound frequency? What unit is used to express amplitude?

frequency: the number of waves that pass a given point in a given time; expressed as waves per second (hertz (Hz)) amplitude: is the height of the sine wave crest; expressed as decibels (dB)

49. Which of the papillae identified above (#48) contain taste buds

fungiform, vallate, foliate

70. Describe the hair cells of the spiral organ. How does an inner hair cell transduce a stimulus? What is the role of the outer hair cells?

inner hair cells: the "hairs" protruding from the apex of a cochlear hair cell are microvilli called stereo cilia. transduction of sound stimuli occurs when the basilar membrane vibrates, causing the hair cells to move with it. the hairs of the hair cell protrude into the K+ rich endolymph and the longest are enmeshed in the tectorial membrane above. as they pivot they open and close ion channels, generating an electrical signal. outer hair cells: act on the basilar membrane itself. when outer hair cells depolarize/hyperpolarize as the basilar membrane moves they contract and stretch (fast motility). this increases the responsiveness of the inner hair cells by amplifying the motion of the basilar membrane and helps protect the inner hair cells from damage

6. Identify and describe the 2 parts of the fibrous layer.

it is composed of the sclera, which forms the posterior portion and the majority of the fibrous layer. the sclera is seen as the "white of the eye" and protects and shapes the eyeball + provides a sturdy anchoring site for extrinsic eye muscles. it's also composed of the cornea, which allows light to enter the eye. the cornea is covered by an external sheet of stratified squamous epithelium that protects it from abrasion, and the deeper corneal endothelium composed of simple squamous epithelium that lines the inner face of the cornea and keeps its water content low

18. The optic disc is referred to as the "blind spot" because it is a region of the retina that does not contain photoreceptors? What is located in the optic disc?

it is the point where the optic nerve fibers leave the retina

36. How does the release of activated opsin during this cycle (#35) alter the rate of neurotransmitter release by photoreceptor cells?

light activated rhodopsin activates transducer (G protein) which then activates phosphodiesterase (PDE). PDE converts cGMP to GMP, causing cGMP levels to fall. as cGMP levels fall previously cGMP gated channels close, causing hyper polarization and preventing AP from occurring

79. Identify and describe the function of the two types of cells in the maculae of the utricle and saccule

maculae - sensory receptor for static equilibrium supporting cells - surround hair cells hair cells - respond to acceleration and head tilting, many stereocilia and one kinocilium, in otolithic membrane; synapse with fibers of the vestibular nerve

75. Identify factors that increase the risk of hearing loss

male gender, increased age, genetic predisposition, exposure to secondhand smoke, use of ototoxic medications, education level less than or equal to high school diploma, and certain medical conditions

59. Name the auditory ossicles and describe their position within the middle ear.

malleus: base secured to ear drum incus: between malleus and stapes stapes: base fits into oval window

87. Identify and differentiate why a person may experience dizziness

motion sickness vertigo dehydration low BP drug toxicity

51. What part of the gustatory receptor cell is the stimulus transducer?

neurotransmitter

11. Which muscle layer of the iris is under parasympathetic control? sympathetic control?

parasympathetic: sphincter pupillae sympathetic: dilator pupillae

14. Name the three distinct layers of retinal neurons from outermost to innermost.

photoreceptors bipolar cells ganglion cells

39. Explain the basic processing of visual input that occurs in the retina

retinal cells simplify and condense the information from rods and cones; splits into different channels that include information about color and brightness also angle, direction and speed of movement

16. Name and describe the specific functions of the two types of photoreceptors.

rods: dim light and peripheral vision receptors. more numerous, more sensitive to light than cones. do not provide sharp images or color vision. cones: vision receptors for bright light and provide high resolution color vision.

60. Describe the process through which the tympanic membrane and ossicles work together to transmit and amplify sound waves

soundwaves vibrate tympanic membrane, vibrate the bones, stapes vibrates on the round window and move the fluid in the internal ear exciting hearing receptors

77. Identify and define the two types of equilibrium.

static equilibrium: linear acceleration and position of head with respect to gravity dynamic equilibrium: changes in head rotation

78. Which vestibular structure(s) are associated with dynamic equilibrium? with static equilibrium?

static equilibrium: vestibule, maculae dynamic equilibrium: semicircular canals

52. What are the five primary taste sensations?

sweet, sour, salty, bitter, umami

9. Describe the structural relationship between the ciliary body, ciliary processes, ciliary zonule (aka suspensory ligament), and lens of the eye. How do these structures work together in accommodation for near vision?

the ciliary muscle and ciliary zonule focus an image by changing the shape of the lens. sympathetic input (distant vision) relaxes ciliary muscle. this tightens the ciliary zonule and flattens the lens. parasympathetic input (near vision) contracts ciliary muscle. this loosens the ciliary zonule and allows the lens to bulge.

22. What two eye structures account for virtually all of the eye's refractive ability?

the cornea and the lens

85. How is a rotational movement stimulus transduced?

the endolymph in the semicircular ducts moves briefly in the direction opposite the body's rotation, deforming the crista in the duct. as the hairs bend, the hair cells depolarize and impulses reach the brain at a faster rate. bending the cilia in the opposite direction causes hyperpolarization and generates fewer impulses; endolymph eventually comes to rest until we stop moving some ampulla are hyperpolarized and some are depolarized because they are in different planes

23. What is the functional significance of the far point of vision?

the far point of vision is the distance beyond which no change in lens shape is needed for focusing. for the normal eye (emmetropic) the far point is about 20ft

67. Describe the spiral organ (aka organ of Corti), noting its relationship to the basilar and tectorial membranes.

the spiral organ is located within the cochlear duct. it sits on top of the basilar membrane an under the tectorial membrane

82. Describe the relationship of the semicircular canals with respect to each other.

they are located in all three planes of space

88. CNS integration of balance and orientation of the body in space occurs in the cerebellum and vestibular nuclei of the brain stem and involves analysis and integration of input from what three types of receptors?

vestibular somatic visual

86. Which cranial nerve conducts sensory nerve impulses regarding static and dynamic equilibrium?

vestibulocochlear (CN VIII)

20. Where is vitreous humor located and what is its function?

vitreous humor is a clear gel located in the posterior segment of the eye. it transmits light, supports the posterior surface of the lens, holds the neural layer of the retina against the pigmented layer, contributes to intraocular pressure, and helps counteract the pulling force of the extrinsic eye muscles