Anatomy Test Bank Chapter

Exam Name___________________________________ SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question. Figure 15.1 Using Figure 15.1, match the following: 1) Ganglion cells. Answer: E 2) Bipolar cells. Answer: C 3) Horizontal cell. Answer: A 4) Amacrine cell. Answer: D 5) Rod. Answer: B 1 Figure 15.2 Using Figure 15.2, match the following: 6) Protects and shapes the eyeball; provides a sturdy anchoring site for extrinsic eye muscles. Answer: A 7) Blood vessels that supply nutrition to most of the eyes' structures (excluding the lens and cornea). Answer: B 8) Contains only cones; provides detailed color vision. Answer: D 9) Lacks photoreceptors; where optic nerve exits the eye. Answer: E 10) Consists of a pigmented layer and a neural layer. Answer: C 2 Figure 15.3 Using Figure 15.3, match the following: 11) Acts as a reflexively activated diaphragm to vary pupil size. Answer: C 12) The only tissue in the body that can be transplanted from one person to another with little or no rejection. Answer: B 13) Controls lens shape. Answer: A 14) Viscous liquid that holds the retina firmly against the pigmented layer. Answer: E 15) Increased pressure here causes glaucoma. Answer: D 3 Figure 15.4 Using Figure 15.4, match the following: 16) Auricle. Answer: A 17) Tympanic membrane. Answer: E 18) Stapes. Answer: C 19) Semicircular canals. Answer: B 20) Cochlea. Answer: D 21) Balance organ. Answer: B 22) Houses organ of Corti. Answer: D 4 MATCHING. Choose the item in column 2 that best matches each item in column 1. Match the following: 23) The sensory layer of the eye. A) Retina Answer: A B) Aqueous humor 24) The structure most responsible for focusing light rays that enter the eye. C) Fovea centralis Answer: D 25) Helps maintain the intraocular pressure; located in the anterior part of the eye. D) Lens Answer: B 26) Area of greatest visual acuity. Answer: C Match the following: 27) Ear stones. A) Otoliths Answer: A B) Tympanic membrane 28) Connects the middle ear with the nasopharynx. C) Vestibule Answer: D 29) Separates external acoustic meatus from the middle ear. D) Pharyngotympanic tube Answer: B 30) Contains utricle and saccule. Answer: C 31) Detects linear acceleration. Answer: C Match the following: 32) A condition that can result from a deficiency of vitamin A. A) Night blindness Answer: A 5 33) A condition of deafness that may result from otosclerosis. Answer: B 34) An inflammation of the lining of the middle ear. A) Otitis media B) Conduction deafness C) Glaucoma Answer: A 35) A condition often leading to blindness due to chronic persistent intraocular pressure. Answer: C Match the following: 36) Hair cells receptive to changes in dynamic equilibrium are found in this structure. A) Macula B) Spiral organ (of Corti) Answer: E 37) Chemically sensitive microvilli found in this structure. Answer: F 38) Hair cells receptive to changes in static equilibrium are found in this structure. Answer: A 39) Chemically sensitive cilia are found in this structure. C) Olfactory epithelium D) Tympanic membrane E) Crista ampullaris F) Taste buds G) Cochlear duct H) Vestibule Answer: C 40) Houses the spiral organ (of Corti). Answer: G 41) The receptor organ for hearing. Answer: B 42) The central part of the bony labyrinth. Answer: H 43) A membrane that transmits sound vibrations to the auditory ossicles. Answer: D 6 Match the following: 44) Loss of hearing resulting from prolonged exposure to high intensity sounds. A) Sensorineural deafness B) Conduction deafness Answer: A 45) Can result from the fusion of the auditory ossicles. C) Tinnitus Answer: B 46) A possible side effect of medications such as aspirin. Answer: C 47) One of the most common results of otitis media. Answer: B 48) Can result from impacted cerumen. Answer: B TRUE/FALSE. Write 'T' if the statement is true and 'F' if the statement is false. 49) The mucous membrane that lines the eyelids and is reflected over the anterior surface of the eyeball is the conjunctiva. Answer: True False 50) Vitamin A needed by the photoreceptor cells is stored by the cells of the retina pigmented layer. Answer: True False 51) Static equilibrium involves the sensation of linear acceleration as well as changes in head rotation. Answer: True False 52) The optic disc forms a blind spot where the optic nerve leaves the eyeball. Answer: True False 53) Sour taste receptors are stimulated by hydrogen ions of acidic food substances. Answer: True False 54) The fluid contained within the membranous labyrinth is called perilymph. Answer: True False 55) Precision of eye movement is due to the fact that extrinsic eye muscle motor units typically innervate 8 to 12 muscle cells and in some cases as few as 2 or 3 muscle cells. Answer: True False 56) Ciliary muscles are considered voluntary, skeletal muscle. Answer: True False 7 57) The structure that allows equalization of the pressure in the middle ear with the atmospheric pressure is the external auditory meatus. Answer: True False 58) The bending of light rays is called reflection. Answer: True False 59) The anterior chamber of the eye is filled with vitreous humor. Answer: True False 60) The neural layer of the retina prevents excessive scattering of light within the eye. Answer: True False 61) In order for sound to reach the spiral organ (of Corti), the auditory ossicles must vibrate the oval window and set the endolymph in motion. Answer: True False 62) Sound is generally perceived in the occipital lobe of the cerebral cortex. Answer: True False 63) Light passes through the entire thickness of the neural layer of the retina to excite the photoreceptors. Answer: True False 64) Without a functioning crista ampullaris, the semicircular canals would not function. Answer: True False 65) Contraction of the ciliary muscle causes the lens to bend the light less. Answer: True False 66) Theoretically, an individual born without a middle ear would be able to hear by bone conduction with a hearing aid. Answer: True False 67) When we move from darkness to bright light, retinal sensitivity is lost, but visual acuity is gained. Answer: True False 68) The function of the lens of the eye is to allow precise focusing of light on the retina. Answer: True False 69) Odorants must be volatile to be smelled. Answer: True False 70) Hair cells in the spiral organ of the ear are never replaced. Answer: True False 71) The quality of a sound is based on the atmospheric pressure at the time the sound is generated. Answer: True False 8 MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 72) Nutrients are delivered and waste products are carried away from the cells of the posterior segment of the eye by blood vessels. However, the cells in the cornea and lens (in the anterior segment) are avascular. Which is the best explanation for how these cells are maintained? A) The aqueous humor is continuously replenished and flows from the ciliary process to drain in the scleral venous sinus. B) The nutrients and waste products of the anterior segment diffuse into and through the vitreous humor of the posterior segment. C) These cells, like the cells of the corneal layer of the integument are not living cells. D) The metabolic activity of these cells is very low. They produce little waste and need few nutrients. Answer: A 73) In a person who is color blind, which of the following would you most expect to see? A) absence of green or red cones in their foveae B) an inability to regenerate 11 cis retinal after bleaching C) a loss of their peripheral vision D) a loss of functions in the rods of their retina Answer: A 74) Which of the following is the best explanation of why it is difficult to discriminate the color of an object at night? A) At night, dilation of pupils stimulates the retina, where more rods are located rather than cones. B) The foveae are densely packed with cones. C) Cones come in three types, each sensitive to different wavelengths of light. D) As many as 100 cones may converge on one ganglion cell. Answer: A 75) Which of the following best describes the function of the iris? A) gives the eye its color C) controls amount of light entering eye B) refracts light through the pupil D) adjusts the shape of the lens Answer: C 76) Which of the following is the best explanation for our perception of color? A) As many as 100 cones may converge on one ganglion cell. B) The foveae are densely packed with cones. C) Rods contain a single kind of visual pigment. D) Cones come in three types, each sensitive to different wavelengths of light. Answer: D 77) The elasticity of the lens decreases with age. This leads to which of the following? A) less accommodation of the lenses and difficulty focusing on nearby objects B) lowered accommodation of the pupillary reflex and blurry vision C) less light getting to the retina and diminished visual acuity D) a clouding of the lenses known as a cataract Answer: A 78) Paralysis of which eye muscle would prevent the right eye from looking to the left? A) Medial rectus B) Inferior rectus C) Superior rectus Answer: A 9 D) Lateral rectus 79) Overlap in the visual fields of our eyes ________. A) leaves a blind spot anterior to the nose and in the lateral fields of vision B) gives us higher visual acuity for small detail by doubling the number of photoreceptors that are being stimulated C) is essentially a waste of brain processing for what is essentially the same image D) allows us to subconsciously estimate the distance of objects based on the different angles the image strikes our two retinas Answer: D 80) If you shine a light into one eye both pupils will constrict. The best explanation for this is ________. A) information from one eye is directly and immediately transferred to the other eye to maintain alignment of the eyes B) a small portion of light always enters the other eye C) sensory input from the retinas of both eyes converges at the optic chiasm and information from each eye is delivered to both the left and right sides of the brain D) This, in fact, does not occur; information from both eyes is always separated. Answer: C 81) Select the statement below that is NOT true with regards to the process of light adaptation. A) Rhodopsin is uncoupled from light transduction. B) Visual acuity is diminished. C) Retinal sensitivity decreases. D) The activity of rods is reduced by rapid bleaching of rhodopsin. Answer: B 82) Humans can see several thousand shades of color but have cone photoreceptors that are sensitive to only three (perhaps four) wavelengths of light. What is the best explanation for why we see so many colors? A) Color perception is dependent on the millions of rods as well as cone photoreceptors. B) Shades of color are purely psychological and learned by association with age, infants only seeing in black and white. C) Colors are added and enhanced in the primary visual cortex of the brain. D) Color perception is achieved by activation of various combinations between the three cone types. Answer: D 83) Color vision has much greater resolution than night vision (vision that is mostly in shades of gray). Which of the following is the best explanation for why this is so? A) There are several types of cone photoreceptors, each of which enrich the clarity and resolution of vision. B) A single cone photoreceptor often connects to a single bipolar cell and a single ganglion cell while as many as 100 rods will converge to a single ganglion cell. C) There are many more cone photoreceptors in the eye than rod photoreceptors. D) A larger proportion of the brain's visual cortex is active during the day when our cone photoreceptors are most active. Answer: B 10 84) Humans can smell as many as 10,000 different odors but have significantly fewer types of olfactory receptors. Which of the following is the best explanation for why humans can distinguish so many smells? A) Taste receptors that are active at the same time influence the subtlety of what we smell. B) The sensation of a single, distinct smell is a combination of a variety of chemicals that stimulate different combinations of olfactory receptor cells all at once. C) The belief that we can smell so many different distinct odors is a psychological process referred to as an uncinate fit or olfactory hallucination. D) The olfactory pathway travels to location in the brain in which memories are formed and we simply mix this new sensory information with old memories. Answer: B 85) As light travels through the eye, it passes through several structures or chambers before reaching the retina. Which list below gives those structures in the correct order? A) cornea, pupil, lens, anterior chamber, posterior segment B) cornea, lens, pupil, anterior chamber, posterior segment C) cornea, pupil, anterior chamber, lens, posterior segment D) cornea, anterior chamber, pupil, lens, posterior segment Answer: D 86) Labyrinthitis is a medical condition often caused by a viral infection, resulting in swelling and inflammation of the membranous labyrinth. Which of the following symptoms would you most associate with the condition of labyrinthitis? A) loss of hearing B) auditory hallucination C) loss of balance and dizziness D) ringing in the ears (tinnitus) Answer: C 87) The sensation of loudness or the volume of a sound is detected by ________. A) faster vibration of the basilar membrane resulting in a higher frequency of hair cell stimulation B) vibration along a greater length of the basilar membrane, stimulating a greater number of hair cells C) greater movement of the basilar membrane resulting in greater deflection of the hair cells D) sounds that can travel all the way to the apex of the scala vestibule with enough energy remaining to deflect hair cells Answer: C 88) A patient has a loss of hearing in only one ear. Which of the following is likely to be a result? A) The patient will have increased sensitivity to sound in the unaffected ear. B) The patient will not be able to localize the origin of sounds. C) The patient will not be able to track objects with the eye on the same side as the hearing loss. D) The patient will have a loss of balance with dizziness and vertigo. Answer: B 11 89) Dancers will use a technique called "spotting" when they perform spins of the body. By holding their head and eyes on a fixed point in front of them as their body spins they reduce the amount of head spinning and this prevents dizziness. Which of the following is the most likely explanation for why this works? A) This will help to reduce the lateral flection of the head and will prevent hyper polarization or depolarization of the hair cells in the macula. B) When the eyes send a static vision of stability to the brain, it is tricked into believing the body is still and therefore dizziness will not occur. C) Reducing the inertia of head spin will reduce the flow of endolymph that deflects the hair cells of the crista ampullaris. D) This helps keep the motions detected by the eyes congruent (aligned) with the motions sensed by the vestibular apparatus. Answer: C 90) Tom is a 45 year old male that has lost his ability to hear high frequency sounds. The most likely explanation for this would be ________. A) a perforated tympanic membrane B) a middle ear infection C) an overgrowth of bony tissue, fusing the ossicles together D) damage to the hair cells near the oval window in the cochlear duct Answer: D 91) What is the main function of the rods in the eye? A) accommodation for near vision C) vision in dim light B) color vision D) depth perception Answer: C 92) What structure regulates the amount of light passing to the visual receptors of the eye? A) cornea B) aqueous humor C) iris D) lens Answer: C 93) Receptors for hearing are located in the ________. A) tympanic membrane C) semicircular canals B) cochlea D) vestibule Answer: B 94) Which of the following types of neurons are replaced throughout adult life? A) retinal bipolar cells B) retinal ganglion cells C) auditory outer and inner hair cells D) olfactory receptor cells Answer: D 95) Bitter taste is elicited by ________. A) metal ions B) hydrogen ions C) alkaloids Answer: C 96) The receptor for static equilibrium is the ________. A) macula C) cochlear duct B) semicircular canals D) utricle Answer: A 12 D) acids 97) The ability to clearly see objects at a distance but not close up is properly called ________. A) myopia B) hyperopia C) hypopia D) presbyopia Answer: B 98) Seventy percent of all sensory receptors are located in the ________. A) skin B) ears C) eye D) nose Answer: C 99) Which of the following structures is NOT part of the external ear? A) external acoustic meatus B) pinna C) tympanic membrane D) pharyngotympanic tube Answer: D 100) Nerve fibers from the medial aspect of each eye ________. A) go to the superior colliculus only B) divide at the chiasma, with some crossing and some not crossing C) pass posteriorly without crossing over at the chiasma D) cross over to the opposite side at the chiasma Answer: D 101) Ordinarily, it is NOT possible to transplant tissues from one person to another, yet corneas can be transplanted without tissue rejection. This is because the cornea ________. A) has no nerve supply B) is not a living tissue C) has no blood supply D) does not contain connective tissue Answer: C 102) The oval window is connected directly to which passageway? A) scala vestibuli C) scala tympani B) pharyngotympanic tube D) external acoustic meatus Answer: A 103) There are three layers of neurons in the retina. The axons of which of these neuron layers form the optic nerves? A) bipolar cells B) cone cells C) rod cells D) ganglion cells Answer: D 104) The first "way station" in the visual pathway from the eye, after there has been partial crossover of the fibers in the optic chiasma, is the ________. A) lateral geniculate body of the thalamus B) temporal lobe C) visual cortex D) superior colliculi Answer: A 105) As sound levels increase in the spiral organ (of Corti), ________. A) inner hair cells bend the cilia away from the kinocilium B) outer hair cells stiffen the basilar membrane C) inner hair cells stiffen the basilar membrane D) outer hair cells bend the cilia away from the kinocilium Answer: B 13 106) Which of the following is true about gustatory receptors? A) The receptors generate an action potential in response to chemical stimuli. B) Complete adaptation occurs in about one to five minutes. C) In order for a chemical to be sensed, it must be hydrophobic. D) All gustatory receptors have the same threshold for activation. Answer: B 107) Taste buds are NOT found ________. A) in filiform papillae C) in circumvallate papillae B) lining the buccal cavity D) in fungiform papillae Answer: A 108) Select the correct statement about olfaction. A) Olfactory adaptation is only due to fading of receptor cell response. B) Some of the sensation of olfaction is actually one of pain. C) Olfactory receptors have a high degree of specificity toward a single type of chemical. D) Substances must be volatile and hydrophobic in order to activate olfactory receptors. Answer: B 109) Which of the following describes a response of the eye to sympathetic stimulation? A) pupil dilation B) ciliary muscle relaxation C) pupil constriction D) ciliary muscle contraction Answer: A 110) Which of the following taste sensations is incorrectly matched to the chemicals that produce it? A) sweet organic substances such as sugar and some lead salts B) umami triglycerides and fatty acids C) salty metal ions D) sour acids E) bitter alkaloids Answer: B 111) Which best describes the function of olfactory cilia? A) increase surface area of neurons receptive to airborne chemicals B) trap inhaled particulates before air reaches lungs C) help move air through nasal passages D) help transport mucus toward nasopharynx Answer: A 112) What is a modiolus? A) bone around the cochlea B) a bony area around the junction of the facial, vestibular, and cochlear nerves C) bone in the center of a semicircular canal D) a bone pillar in the center of the cochlea Answer: D 14 113) Which statement about malnutrition induced night blindness is most accurate? A) The impaired vision is caused by reduced cone function. B) Visual pigment content is reduced in cones more than rods. C) Vitamin supplements can reverse degenerative changes. D) The most common cause is vitamin D deficiency. Answer: C 114) Dark adaptation ________. A) involves accumulation of rhodopsin B) primarily involves improvement of acuity and color vision C) is much faster than light adaptation D) results in inhibition of rod function Answer: A 115) Conscious perception of vision probably reflects activity in the ________. A) occipital lobe of the cortex B) superior colliculus C) thalamus D) chiasma Answer: A 116) In the visual pathways to the brain, the optic radiations project to the ________. A) optic chiasma B) medial retina C) lateral geniculate body D) primary visual cortex Answer: D 117) Visual inputs to the ________ serve to synchronize biorhythms with natural light and dark. A) superior colliculi B) pretectal nuclei C) lateral geniculate body D) suprachiasmatic nucleus Answer: D 118) Which of the following types of receptors are located in the mouth? A) chemoreceptors, mechanoreceptors, thermoreceptors, and nociceptors B) thermoreceptors, mechanoreceptors, and nociceptors only C) chemoreceptors only D) chemoreceptors, thermoreceptors, and nociceptors only Answer: A 119) Motion sickness seems to ________. A) result from mismatch between visual and vestibular inputs B) respond best to medication that "boosts" vestibular inputs C) respond best to medication taken after salivation and pallor begins D) result from activation of nausea centers in the brain stem Answer: A 120) The only special sense NOT fully functional at birth is the sense of ________. A) vision B) hearing C) equilibrium D) taste Answer: A 15 E) smell 121) Most newborns ________. A) are myopic B) often use only one eye at a time C) produce more tears when they cry than a toddler D) see in tones of red and green only Answer: A 122) The blind spot of the eye is caused by ________. A) an absence of photoreceptors where the optic nerve leaves the eye B) an absence of cones in the foveae C) more rods than cones within the retina D) the macula lutea interrupts the nerve pathway Answer: A 123) The first vestiges of eyes in the embryo are called ________. A) optic cups B) optic vesicles C) mesenchyme D) optic discs Answer: B 124) Which pairing of terms is incorrectly related? A) amplitude of a sound: intensity of the sound B) frequency of sound waves: loudness of the sound C) quality of a sound: frequency of the sound D) frequency of sound waves: number of wavelengths Answer: B 125) A patient who has experienced previous jaw and face trauma now reports difficulty tasting with the tip of her tongue. Which cranial nerve was likely damaged in that injury? A) Facial (VII) B) Glossopharyngeal (IX) C) Hypoglossal (XII) D) Trigeminal (V) Answer: A 126) Which of the following could NOT be seen as one looks into the eye with an ophthalmoscope? A) fovea centralis B) optic disc C) macula lutea D) optic chiasma Answer: D 127) The cells of the retina in which action potentials are generated are the ________. A) amacrine cells B) rods and cones C) ganglion cells D) bipolar cells Answer: C 128) During dark adaptation, ________. A) the cones are activated C) rhodopsin accumulates in the rods B) the rate of rhodopsin breakdown is accelerated D) the sensitivity of the retina decreases Answer: C 129) Tinnitus, vertigo, and gradual hearing loss typify the disorder called ________. A) motion sickness B) strabismus C) conjunctivitis D) Ménière's syndrome Answer: D 16 130) Which of the following is NOT a characteristic of olfactory receptor cells? A) They are ciliated. B) They are chemoreceptors. C) They are unipolar neurons. D) They have a short life span of about 60 days. Answer: C 131) An essential part of the maculae involved in static equilibrium is (are) the ________. A) scala media B) otoliths C) spiral organ (of Corti) D) cupula Answer: B 132) What is the primary function of cerumen? A) cleans and lubricates the external auditory canal B) lubricates ossicles C) softens tympanic membrane D) prevents water from entering middle ear Answer: A 133) Which of the following is true about photoreceptors? A) Three types of color sensitive photoreceptors exist: red, green, and yellow. B) If all cones are stimulated equally, all colors are absorbed by the cones and the color perceived is black. C) Rods absorb light throughout the visual spectrum but confer only gray tone vision. D) In dim light, images are focused directly on the rods in the fovea centralis. Answer: C 134) Select the correct statement about equilibrium. A) Hair cells involved in both static and dynamic equilibrium hyperpolarize only, resulting in an increased rate of impulse transmission. B) The weight of the endolymph contained within the semicircular canals against the maculae is responsible for static equilibrium. C) Cristae respond to angular acceleration and deceleration. D) Due to dynamic equilibrium, movement can be perceived if rotation of the body continues at a constant rate. Answer: C 135) The eye muscle that rotates the eye upward and turns the eye laterally is the ________. A) inferior oblique B) medial rectus C) superior oblique D) lateral rectus Answer: A 136) The receptor membranes of gustatory cells are ________. A) basal cells B) taste buds C) gustatory hairs D) fungiform papillae Answer: C 137) A perceived increase in the volume of sound is best explained by ________. A) a combination of multiple sound waves B) an increase in the height of the sound wave C) an increase in the width of the sound wave D) a decrease in the width of the sound wave Answer: B 138) Damage to the medial rectus muscles would probably affect ________. A) pupil constriction B) refraction C) accommodation Answer: D 17 D) convergence 139) Which movement of ions produces EPSPs in cochlea hair cells? A) Influx of Na C) Influx of K and Ca B) Efflux of Ca D) Efflux of K Answer: C 140) Fusing of the ossicles (otosclerosis) results in ________. A) sensorineural deafness C) Ménière's Syndrome B) conduction deafness D) tinnitus Answer: B 141) Visual processing in the thalamus does NOT contribute significantly to ________. A) night vision B) depth perception C) movement perception D) high acuity vision Answer: A 142) The visible light portion of the electromagnetic spectrum fits between ________. A) UV and infrared waves B) X rays and UV waves C) infrared and microwaves D) microwaves and radio waves Answer: A 143) Ceruminous glands are ________. A) modified apocrine sweat glands C) glands found in the lateral corners of your eye B) saliva glands found at the base of the tongue D) modified taste buds Answer: A SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question. 144) High frequency sounds are detected when the basilar membrane is displaced near the ________. Answer: base 145) The synapse of the olfactory nerves with the mitral cells is called a(n) ________. Answer: glomerulus 146) The middle ossicle in the ear is the ________. Answer: incus 147) The ________ nuclei are in the visual pathway and mediate the pupillary light reflexes. Answer: pretectal 148) Taste is solely a response to chemicals dissolved in ________. Answer: saliva 149) Hot chili peppers contain a chemical compound called capsaicin that stimulate which type of receptor? Answer: Nociceptors 150) The apex of the cochlea hears sounds in the range of ________ Hz. Answer: 20 18 151) Describe the process of light and dark adaptation and include the role of the rods and cones. Answer: Rods respond to low intensity light that provides night and peripheral vision, while cones are bright light, high discrimination receptors that provide color vision. During light adaptation, rods are inactivated and as cones respond to the high intensity light, high visual acuity results. In dark adaptation, cones do not function (visual acuity decreases) and rod function resumes when sufficient rhodopsin accumulates. 152) What is the chemical composition of the rod pigment, rhodopsin, and how does it appear to act in the reception of light? Answer: Rhodopsin is a combination of retinal and opsin. Retinal is chemically related to vitamin A and is synthesized from it. Retinal can form a variety of three dimensional forms called isomers. The opsin protein combines with the 11 cis retinal to form rhodopsin. The light triggered changes in retinal cause hyperpolarization of the rods. This happens because the light turns off sodium entry, which then inhibits the release of neurotransmitter, thus turning off electrical signals. 153) After head trauma from an automobile accident, a man has anosmia. Define anosmia. Why is this condition fairly common after such injuries and in cases of severe nasal cavity inflammation? Answer: Anosmia means the loss of chemical sense of smell due to some olfactory disorder. Most anosmia results from head injuries or nasal cavity inflammations, allergies, smoking, and aging. The olfactory pathways are very sensitive to irritations or to damage, especially if the ethmoid bones have been damaged due to trauma. 154) Explain why your nose runs during and immediately after a good cry. Answer: The tears flow into the lacrimal canaliculi and then into the nasolacrimal sac. As the sac fills, the tears begin to run down the nasolacrimal duct and out your nose. 155) Trace the pathway of sound as it enters the external ear until it is perceived in the brain. Answer: A sound wave passing through the external acoustic meatus causes the eardrum to vibrate at the same frequency as the wave. The auditory ossicles amplify and deliver vibrations to the oval window. Pressure waves in the cochlear fluids cause basilar membrane resonance that stimulates the hair cells of the spiral organ (of Corti). Impulses are then generated along the cochlear nerve that travel to the cochlear nuclei of the medulla and, from there, through several brain stem nuclei to the auditory cortex of the brain. 156) Explain the role of the endolymph of the semicircular canals in activating the receptors during angular motion. Answer: The crista ampullaris responds to changes in the velocity of head movement (angular acceleration). The crista consists of a tuft of hair cells whose microvilli are embedded in the gelatinous cupula. Rotational movement causes the endolymph to flow in the opposite direction, thus bending the cupula and exciting the hair cells. 157) What two things does the ciliary body do? Answer: 1. Constriction of the ciliary muscle that is attached to the lens via the ciliary zonule causes the lens to chan shape. 2. The epithelium of the ciliary body secretes aqueous humor. 158) When you go to the fair and ride the roller coaster, where do those wild sensations come from? Answer: The wild sensations occur when the receptor for dynamic equilibrium, the crista ampularis, is excited by endolymph moving in the semicircular canals. This movement is the result of rotational acceleration or deceleration. Many times these wild rides spin us around enough that our eyes tell us we are going one way but the vestibule and semicircular canal tell us something different. Conflicts like that can often cause us to get quite dizzy or even sick. 19 159) What is the pharyngotympanic tube and what is its purpose? Answer: The pharyngotympanic tube links the middle ear cavity with the nasopharynx. Normally it is flattened and closed, but swallowing or yawning opens it briefly to equalize pressure in the middle ear cavity with external air pressure. It also replenishes air in the middle ear. 160) Explain why prolonged periods of reading tire the eye muscles and result in eye strain. Answer: Reading or other close work requires almost continuous accommodation, pupillary constriction, and convergence, which lead to tiredness of the eye muscles. 161) Distinguish between the maculae and cristae ampullaris in terms of their sensory reception. Answer: Maculae are sensory receptors for static equilibrium. They monitor the position of the head in space by responding to linear acceleration forces. Cristae ampullaris respond to rotary (angular) movements. 162) Explain why a bad cold can result in food not tasting the same as it normally does. Answer: Taste is 80% smell. When the ability to smell is blocked due to nasal congestion, taste is primarily via the taste receptors which account for only about 20% of the taste sensation. This results in a distinct difference in the "taste" of food. Additionally, you become a mouth breather and the oral mucosa becomes dry and reduces the ability to taste ESSAY. Write your answer in the space provided or on a separate sheet of paper. 163) Roger went for his yearly eye examination and was informed that his intraocular pressure was slightly elevated (at 22 mm Hg). The physician expressed concern over this condition and noted that if the condition got worse, eye drops would be merited. What is wrong with Roger's eyes, and what are the possible consequences of this condition? Explain the function of eye drops used for therapy. Answer: If the drainage of the aqueous humor is blocked, pressure within the eye can increase, causing compression of the retina and optic nerve, resulting in a condition called glaucoma. The resulting destruction of the neural structures causes blindness unless the condition is detected early. Early glaucoma can be treated with eye drops that increase the rate of aqueous humor drainage or decrease its production. 164) Baby Susie's pediatrician notices that one of her eyes rotates outward and that she does not appear to be using it for vision. What is her condition and what does the pediatrician recommend? Answer: Susie has strabismus, caused by congenital weakness of the external eye muscles in her affected eye. To prevent this eye from becoming functionally blind, the doctor will recommend either eye exercises or putting a patch on the unaffected eye to force her to use the affected eye. If her case is deemed severe, surgery on the eye muscles will be recommended. 165) A 60 year old woman is experiencing vertigo. She ignores the symptoms initially, but now her attacks are accompanied by severe nausea and vomiting. Following an attack, she hears a roaring in her ears that causes temporary deafness for some time after. What do you think her problem is, and what is its suspected cause? Answer: She most likely has a condition known as Ménière's syndrome. It affects both the semicircular canals and the cochlea. The cause of the syndrome is uncertain, but it may result from distortion of the membranous labyrinth by excessive endolymph accumulation. Less severe cases can usually be managed by antimotion drugs. For more debilitating attacks, salt restriction and diuretics are used to decrease overall extracellular fluid volumes. Also, wearing a visor (baseball hat) reduces the visual field and allows the person to enhance their depth perception and reduce the dizziness. 20 166) Ling, a 75 year old grandmother, complained that her vision was becoming obscured. Upon examination by an ophthalmologist she was told she had cataracts. What are they, how do they occur, and how are they treated? Answer: A cataract is a clouding of the lens that causes the world to appear distorted, as if looking through frosted glass. Some cataracts are congenital, but most are due to age related hardening and thickening of the lens, or are a possible consequence of diabetes mellitus. The direct cause is probably inadequate delivery of nutrients to the deeper lens fibers. The metabolic changes that result are thought to promote unfolding of the lens proteins. Unprotected exposure to the UV rays of sunlight over time is also associated with cataract formation. The lens can be removed and replaced with an artificial lens. 167) A nurse is administering Pilocarpine eye drops. The nurse instructs the patient to press on the nasolacrimal duct for 30 seconds because the medication can have some systemic side effects, such as affecting the heart rate. Explain the rationale for pressing on the nasolacrimal duct. Answer: Applying gentle pressure to the nasolacrimal duct prevents the delivery of the drug to the nasal mucosa and general circulation, where it may affect heart rate. 21