Chapter 15: The Special Senses
Which part of the visual field would be affected by a tumor in the right visual cortex? By a tumor compressing the right optic nerve??
A tumor in the right visual cortex would affect the left visual field. A tumor compressing the right optic nerve would affect both the left and right visual fields from the right eye only.
Sam's optometrist tells him that his interocular pressure is high. What is this condition called and which fluid does it involve?
An increase in intraocular pressure is called glaucoma and is due to an accumulation of aqueous humor, usually because of impaired drainage of the fluid.
What does bleaching of the pigment mean and when does it happen?
Breakdown of the retinal-opsin combination is called bleaching of the pigment. It occurs with exposure to light.
List possible causes and symptoms of otitis media, deafness, and Meniere's syndrome.
Deafness is any hearing loss, no matter how slight. Tinnitus is a ringing or clicking sound in the ears in the absence of auditory stimuli. Meniere's syndrome is a labyrinth disorder that causes a person to suffer repeated attacks of vertigo, nausea, and vomiting.
Outline the causes and consequences of cataracts and glaucoma.
If the drainage of aqueous humor is blocked, fluid backs up as in clogged sink. Pressure within the eye may increase to dangerous levels and compress the retina and optic nerve - a condition called glaucoma. The eventual result is blindness unless the condition is detected early. A cataract is a clouding of the lens that causes the world to appear distorted, as if seen through a frosted glass. Some cataracts are congenital, but most result from age-related hardening and thickening of the lens or are a secondary consequence of diabetes mellitus.
Trace the visual pathway to the visual cortex, and briefly describe the steps in visual processing.
In order for perception to occur, the physiological signal that starts in the retina must travel to the visual cortex. The visual pathway to the brain begins with the optic nerve fibers (ganglion cell axons) from the retina. The retinal ganglion cells merge in the back of the eyeball to become the optic nerve, which crosses at the optic chiasma to become the optic tracts. The optic tracts send their axons to neurons within the lateral geniculate body of the thalamus. Axons from the thalamus project through the internal capsule to form the optic radiation of fibers in the cerebral white matter. These fibers project to the primary visual cortex in the occipital lobes. Visual processing begins in the retina and occurs when the action of light on photoreceptors hyperpolarizes them, which causes the bipolar neurons from both the rods and cones to ultimately send signals to their ganglion cells.
Compare and contrast light and dark adaptation.
Light adaptation occurs when we move from darkness into bright light, as when leaving a movie theater. We are momentarily dazzled - all we see is white light - because the sensitivity of the retina is still "set" for dim light. Both rods and cones are strongly stimulated, and large amounts of the visual pigments break down almost instantaneously, producing a flood of signals that accounts for the glare. Dark adaptation, essentially the reverse of light adaptation, occurs when we go from a well-lit area into a dark area. Initially, we see nothing but velvety blackness because (1) our cones stop functioning in low-intensity light, and (2) the bright light bleached out rod pigments, and the rods are still turning off.
Arrange the following in order that light passes through them to reach the photoreceptors (rods and cones) in the retina: lens, bipolar cells, vitreous humor, cornea, aqueous humor, ganglion cells.
Light passes through the cornea, aqueous humor, lens, vitreous humor, ganglion cells and bipolar cells before it reaches the photoreceptors.
Explain how we are able to differentiate pitch and loudness, and localize the source of sounds.
Loudness refers to our subjective interpretation of sound intensity. Sound intensity (and loudness) is measured in logarithmic units called decibels (dB). Perception of Pitch - Sound waves of different frequencies activate hair cells in different positions along the length of the basilar membrane, and impulses from specific hair cells are interpreted as specific pitches. Detection of Loudness - Louder sounds cause larger movements of the tympanic membrane, auditory ossicles, and oval window, and pressure waves of greater amplitude in the fluids of the cochlea. Localization of Sound - Several brain stem nuclei (most importantly the superior olivary nuclei) help us localize a sound's source in space by means of two cues: the relative intensity and the relative timing of sound waves reaching the two ears.
Describe the events that convert light into a neural signal.
Once light is focused on the retina, the photoreceptors come into play. Phototransduction is the process by which light energy is converted into a graded receptor potential. Two types of photoreceptors in the retina mediate the light response: the rods which mediate vision in dim light and the cones which mediate bright light and color vision.
Compare and contrast the roles of rods and cones in vision.
Rods: - Noncolor vision (one visual pigment) - High sensitivity; function in dim light - Low acuity (many rods converge onto one ganglion cell) - More numerous (20 rods for every cone) - Mostly in peripheral retina Cones: - Color vision (three visual pigments) - Low sensitivity; function in bright light - High acuity (one cone per ganglion cell in fovea) - Less numerous - Mostly in central retina
List changes that occur in the special sense organs with aging.
Taste and Smell: - Smell and taste are highly developed at birth. - Women generally have a more acute sense of taste and smell than men. - Beginning in the fourth decade of life, the ability to taste and smell declines as receptors are replaced more slowly than in younger people. Vision: - By the fourth week of development, eyes begin to develop and—even before photoreceptors develop—CNS connections are made. - Vision is the only sense not fully developed at birth. Newborn infants see only in gray tones, exhibit uncoordinated eye movements, and often use only one eye at a time. - By 5 months, vision has improved, and by 5 years, vision is well developed. - With age, the lens loses clarity and the pupil stays partly constricted, decreasing visual acuity in people over 70. Hearing and Balance: - The ear begins to develop in the embryo at 3 weeks. - Newborn infants can hear, but respond reflexively. By the fourth month of life, hearing includes recognition. - With age, the ability to hear high-pitched sounds declines, and hearing loss is exacerbated by exposure to loud noises.
What are tears and what structure secretes them?
Tears (lacrimal fluid) are a dilute saline secretion that contains mucus, antibodies, and lysozyme. They are secreted by the lacrimal glands.
Six-year-old Mohammed has a cold and says his ears feel "full" and he "can't hear well." Explain what has happened in Mohammed's ears. Which type of deafness does Mohammed have - conduction or sensorineural?
The "fullness" in Mohammed's ears is likely due to an accumulation of fluid in the middle ear as a result of his upper respiratory infection ("cold") spreading into his ear. He has a form of conduction deafness.
Which structure inside the spiral organ allows us to differentiate sounds of different pitch?
The basilar membrane allows us to differentiate sound of different pitch.
What is the blind spot and why is it blind?
The blind spot of the eye is the optic disc. It is the part of the retina where to optic nerve exits the eye and it is "blind" because it is a region of the retina that lacks photoreceptors.
Olfactory sensory neurons have cilia and gustatory epithelial cells have hairs. How do these structures help the cells perform their functions?
The cilia and hairs of these receptor cells greatly increase the surface area for sensory receptors.
You have been reading a book for awhile now, and your eyes are beginning to tire. Which intrinsic eye muscles are relaxing as you stare thoughtfully into the distance?
The ciliary muscles and sphincter pupillae relax for distant vision. (If you said the medial rectus muscles also relax, this is true, but remember that the rectus muscles are extrinsic eye muscles, not intrinsic.)
Explain how the balance organs of the semicircular canals and the vestibule help maintain equilibrium.
The equilibrium sense responds to various head movements and depends on input from the internal ear, vision, and information from stretch receptors of muscles and tendons. The sensory receptors for static equilibrium are the maculae. The receptor for dynamic equilibrium is the crista ampullaris, found in the ampulla of the semicircular canals and activated by head movement. Information from the balance receptors goes directly to reflex centers in the brain stem, rather than to the cerebral cortex.
Describe the structure and general function of the outer, middle, and internal ears.
The external ear consists of the auricle (pinna) and the external acoustic meatus, which is lined with skin bearing hairs, sebaceous glands, and ceruminous glands. The middle ear, or tympanic cavity, is a small, air-filled, mucosa-lined cavity in the petrous portion of the temporal bone. It is spanned by the auditory ossicles. The internal ear has two major divisions: the bony labyrinth and the membranous labyrinth. - The vestibule is the central cavity of the bony labyrinth with two membranous sacs suspended in the perilymph, the saccule and the utricle. - The semicircular canals project from the posterior aspect of the vestibule, each containing an equilibrium receptor region called a crista ampullaris. - The spiral, snail-shaped cochlea extends from the anterior part of the vestibule and contains the cochlear duct, which houses the spiral organ (of Corti), the receptors for hearing.
Describe the structure and function of accessory eye structures and eye layers.
The eye is enclosed in the bony orbit and cushioned by fat. The accessory structure of the eye includes the eyebrows, eyelids, conjunctiva, lacrimal apparatus, and extrinsic eye muscles. The eyebrows are short, course hairs that overlie the supraorbital margins of the skull. They help shade the eyes from sunlight and prevent perspiration trickling down the forehead from reaching the eyes. The eyelids are thin, skin-covered folds supported internally by connective tissue sheets called tarsal plates. Eyelids protect and lubricate the eyes by reflex blinking. The conjunctiva is a mucosa that lines the eyelids and covers the anterior eyeball surface. Its mucus lubricates the eyeball surface. The lacrimal apparatus consists of the lacrimal gland (which produces a saline solution containing mucus, lysozyme, and antibodies), the lacrimal canaliculi, the lacrimal sac, and the nasolacrimal duct. The extrinsic eye muscles (superior, inferior, lateral, and medial rectus and superior and inferior oblique) move the eyeballs. The wall of the eyeball is made up of three layers. The outermost fibrous layer consists of the sclera and the cornea. The sclera protects the eye and gives it shape; the cornea allows light to enter the eye. The middle, pigmented vascular layer (uvea) consists of the choroid, the ciliary body, and the iris. The choroid provides nutrients to the eye and prevents light scattering within the eye. The ciliary muscles of the ciliary body control lens shape; the iris controls the size of the pupil. The inner layer, or retina, consists of an outer pigmented layer and an inner neural layer. The neural layer contains photoreceptors (rods and cones), bipolar cells, and ganglion cells. Ganglion cell axons form the optic nerve, which exits via the optic disc ("blind spot").
Name the five taste modalities. Name the three types of papillae that have taste buds.
The five taste modalities are sweet, sour, bitter, salty, and umami. The fungiform, vallate, and foliate papillae contain taste buds.
For each of the following phrases, indicate whether it applies to a macula or a crista ampullaris: inside a semicircular canal, contains otoliths, responds to linear acceleration and deceleration, has a cupula, responds to rotational acceleration and deceleration, and inside the saccule.
The following apply to the macula: "contains otholiths," "responds to linear acceleration or deceleration," and "inside a saccule." The following apply to a crista ampullaris: "inside a semicircular canal," "has a cupula," and "responds to rotational acceleration and deceleration."
For each of the following, indicate whether it applies to rods or cones: vision in bright light, only one type of visual pigment, most abundant in the periphery of the retina, many feed into one ganglion cell, color vision, higher sensitivity, and higher acuity.
The following are characteristics of cones: "vision in bright light," "color vision," and "higher acuity." The following are characteristics of rods: "only one type of visual pigment," "most abundant in the periphery of the retina," "many feed into one ganglion cell," and "higher sensitivity."
Which of the following statements does not correctly describe the spiral organ? a. Sounds of high frequency stimulates hair cells at the basal end b. The "hairs" of the receptor cells are embedded in the tectorial membrane c. The basilar membrane acts as a resonator d. The more numerous outer hair cells are largely responsible for our perception of sound
The more numerous outer hair cells are largely responsible for our perception of sound
Why does your near point of vision move farther away as you age?
The near point moves farther away as you age because the lens becomes less flexible (presbyopia), so that it is unable to assume the more rounded shape required for near vision.
Describe the location, structure, and afferent pathways of smell and taste receptors, and explain how these receptors are activated.
The receptors for taste and smell are chemoreceptors that respond to chemicals in solution. The olfactory epithelium is the organ of smell located in the roof of the nasal cavity. The olfactory receptors are bipolar neurons with a thin apical dendrite that terminates in a knob with several olfactory cilia. To smell a particular odorant, it must be volatile and it must be dissolved in the fluid coating the olfactory epithelium that stimulates the olfactory receptors. In olfactory transduction, an odorant binds to the olfactory receptor, a G protein, and the secondary messenger of cyclic AMP. Axons of the olfactory receptor cells synapse in the olfactory bulbs, sending impulses down the olfactory tracts to the thalamus, hypothalamus, amygdala, and other members of the limbic system. Taste buds, the sensory receptor organs for taste, are located in the oral cavity, with the majority located on the tongue. Taste sensations can be grouped into one of five basic qualities: sweet, sour, bitter, salty, and umami. Physiology of taste: For a chemical to be tasted it must be dissolved in saliva, move into the taste pore, and contact a gustatory hair. Each taste sensation appears to have its own special mechanism for transduction. Afferent fibers carrying taste information from the tongue are found primarily in the facial nerve and glossopharyngeal cranial nerves. Taste impulses from the few taste buds found on the epiglottis and the lower pharynx are conveyed via the vagus nerve. Taste is strongly influenced by smell and stimulation of thermoreceptors, mechanoreceptors, and nociceptors.
Apart from the bony boundaries, which structure separates the external from the middle ear? Which two (non-bone) structures separate the middle from the inner ear??
The tympanic membrane separates the external from the middle ear. The oval and round windows separate the middle from the inner ear.
Outline the cause and consequences of astigmatism, myopia, hyperopia, and presbyopia.
Theoretically, visual problems related to refraction could result from a hyperrefractive (overconverging) or hyporefractive (underconverging) lens or from structural abnormalities of the eyeball. In practice, 99% of refractive problems are related to eyeball shape, either too long or too short. Unequal curvatures in different parts of the cornea or lens leads to blurry images. This refractory problem is astigmatism. Myopia occurs when distant objects focus in front of the retina, rather than on it. The common name for myopia id nearsightedness. Hyperopia, or farsightedness, occurs when the parallel light rays from distant objects focus behind the retina. Presbyopia is a condition that results in the loss of near focusing ability; typical onset is around age 40.
Auditory Tube
Tube that connects the middle ear and the pharynx; also called eustachian tube; see Pharyngotympanic tube
Trace the pathway of light through the eye to the retina, and explain how light is focused for distant and close vision.
Visible light is made up of those wavelengths of the electromagnetic spectrum that excite the photoreceptors. Light is refracted (bent) when passing from one transparent medium to another of different density. Concave lenses disperse light; convex lenses converge light and bring its rays to a focal point. The greater the lens curvature, the more light bends. As light passes through the eye, the cornea and lens bend and focus it on the retina. The cornea accounts for most of the refraction, but the lens allows active focusing for different distances. Focusing for distant vision requires no special movements of the eye structures. Focusing for close-up vision requires accommodation (bulging of the lens), pupillary constriction, and convergence of the eyeballs. Cranial nerve III controls all three reflexes. Refractory problems include presbyopia, myopia, hyperopia, and astigmatism.
Describe the sound conduction pathway to the fluids of the internal ear, and follow the auditory pathway from the spiral organ to the temporal cortex.
We can summarize human hearing in a single sprawling sentence: Sounds set up vibrations in the air that beat against the eardrum that pushes a chain of tiny bones that press fluid in the internal ear against membranes that set up shearing forces that pull on the tiny hair cells that stimulate nearby neurons that give rise to impulses that travel to the brain, which interprets them - and you hear sounds. Sound is a pressure disturbance - alternating area of high and low pressure - produced by a vibrating object and propagated by the molecules of the medium. Frequency is defined as the number of waves that pass a given point in a given time. The amplitude, or height, of the sine wave crests reveals a sound's intensity. The ascending auditory pathway transmits auditory information primarily from the cochlear receptors (the inner hair cells) to the cerebral cortex. Impulses generated in the cochlea pass through the spiral ganglion, where the auditory bipolar cells reside, and along the afferent fibers of the cochlear nerve to the cochlear nuclei of the medulla. From there, neurons project to the superior olivary nucleus, which lies at the junction of the medulla and pons. Beyond this, axons ascend in the lateral lemniscus (a fiber tract) to the inferior colliculus (auditory reflex center in the midbrain), which projects to the medial geniculate nucleus of the thalamus. Axons of the thalamic neurons then project to the primary auditory cortex, which provides conscious awareness of sound. The auditory pathway is unusual because not all of the fibers from each ear cross over to the other side of the brain. For this reason, each auditory cortex receives impulses from both ears.
What age-related changes make it more difficult for the elderly to see at night?
With age, the lens discolors and loses its clarity and the dilator pupillae muscles become less efficient, decreasing the amount of light that reaches the retinas at night.
If the brain stem did not recieve input from both ears, what would you not be able to do?
You would not be able to locate the origin of a sound if the brain stem did not receive input from both ears.
Astigmatism
a condition in which unequal curvatures in different parts of the cornea or lens of the eye lead to blurred vision
Myopia
a condition in which visual images are focused in front of rather than on the retina; nearsightedness
Hyperopia
a condition in which visual images are routinely focused behind rather than on the retina; commonly known as farsightedness
Presbyopia
a condition that results in the loss of near focusing ability; typical onset is around age 40
Ampulla
a localized dilation of a canal or duct
Fovea
a pit
Taste buds are found on the a. anterior part of the tongue b. posterior part of the tongue c. palate d. all of these
all of these
Vestibule
an enlarged area at the beginning of a canal, i.e., inner ear, nose, larynx
Branchial Groove
an indentation of the surface ectoderm in the embryo; the external acoustic meatus develops from it
Fundus
base of an organ; part farthest from the opening of the organ. For example, the posterior wall of the eye
Labyrinth
bony cavities and membranes of the inner ear
Glaucoma
condition in which intraocular pressure increases to levels that cause compression of the retina and optic nerve; results in blindness unless detected early
Activation of the sympathetic nervous system causes a. contraction of the sphincter pupillae muscles b. contraction of the dilator pupillae muscles c. contraction of the ciliary muscles d. a decrease in ciliary zonule tension
contraction of the dilator pupillae muscles
Damage to the medial recti muscles would probably affect a. accommodation b. refraction c. convergence d. pupil constriction
convergence
Tympanic Membrane
eardrum
Electromagnetic Radiation
emitted photons (wave packets) of energy, e.g., light, X ray, infrared
The transmission of sound vibrations through the internal ear occurs chiefly through a. nerve fibers b. air c. fluid d. bone
fluid
During embryonic development, the lens of the eye forms a. as part of the choroid coat b. from the surface ectoderm overlying the optic cup c. as part of the sclera d. from mesodermal tissue
from the surface ectoderm overlying the optic cup
Of the neurons in the retina, the axons of which of these form the optic nerve? a. bipolar cells b. ganglion cells c. cone cells d. horizontal cells
ganglion cells
Blockage of the scleral venous sinus might result in a. a sty b. glaucoma c. conjunctivitis d. a cataract
glaucoma
Pitch is to frequency of sound as loudness is to a. quality b. intensity c. overtones d. all of these
intensity
Which sequence best describes a normal route for the flow of tears from the eyes into the nasal cavity? a. lacrimal canaliculi, lacrimal sacs, nasolacrimal ducts b. lacrimal ducts, lacrimal canaliculi, nasolacrimal ducts c. nasolacrimal ducts, lacrimal canaliculi, lacrimal sacs
lacrimal canaliculi, lacrimal sacs, nasolacrimal ducts
Cells in the olfactory bulb that act as local "integrators" of olfactory inputs are the a. hair cells b. amacrine granule cells c. olfactory stem cells d. mitral cells e. supporting cells
mitral cells
Nearsightedness is more properly called a. myopia b. hyperopia c. presbyopia d. emmetropia
myopia
Retina
neural layer of the eyeball; contains photoreceptors (rods, cones)
Cones
one of the two types of photoreceptor cells in the retina of the eye; provide for color vision
Rods
one of the two types of photosensitive cells in the retina
Pupil
opening in the center of the iris through which light enters the eye
Olfactory nerve filaments are found a. in the optic bulbs b. passing through the cribriform plate of the ethmoid bone c. in the optic tracts d. in the olfactory cortex
passing through the cribriform plate of the ethmoid bone
Lacrimal
pertaining to tears
Ophthalmic
pertaining to the eye
Optic
pertaining to the eye or vision
Which sequence of reactions occurs when a person looks at a distant object? a. pupils constrict, ciliary zonule (suspensory ligament) reflexes, lenses become less convex b. pupils dilate, ciliary zonule become taut, lenses become less convex c. pupils dilate, ciliary zonule become taut, lenses become more convex d. pupils constrict, ciliary zonule (suspensory ligament) reflexes, lenses become more convex
pupils dilate, ciliary zonule become taut, lenses become less convex
The phenomenon of dark adaptation is best explained by the fact that a. rhodopsin does not function in dim light b. rhodopsin breakdown occurs slowly c. rods exposed to intense light need time to generate rhodopsin d. cones are stimulated to function by bright light
rods exposed to intense light need time to generate rhodopsin
The portion of the fibrous layer that is white and opaque is the a. choroid b. cornea c. retina d. sclera
sclera
Static Equilibrium
sense of head position in space with respect to gravity
Dynamic Equilibrium
sense that reports on angular (rotatory) acceleration or deceleration of the head in space
Crista Ampullaris
sensory receptor organ for rotational acceleration and deceleration housed within the ampulla of each semicircular canal of the inner ear
Taste Buds
sensory receptor organs that house gustatory cells, which respond to dissolved food chemicals
Olfaction
smell
Olfactory tract damage would probably affect your ability to a. see b. hear c. feel pain d. smell
smell
Cochlea
snail-shaped chamber of the bony labyrinth that houses the receptor for hearing [the spiral organ (of Corti)]
Photoreceptor
specialized receptor cells that respond to light energy; rods and cones
Conduction of sound from the middle ear to the internal ear occurs via vibration of the a. malleus against the tympanic membrane b. stapes in the oval window c. incus in the round window d. stapes against the tympanic membrane
stapes in the oval window
Gustatory epithelial cells are stimulated by a. movement of otoliths b. stretch c. substances in solution d. photons of light
substances in solution
Refraction
the bending of a light ray when it meets a different surface at an oblique rather than right angle
Visual Field
the field of view seen when the head is still
Optic Chiasma
the partial crossover of fibers of the optic nerves
Accommodation
the process of increasing the refractive power of the lens of the eye; focusing
Special Senses
the senses of taste, smell, vision, hearing, and equilibrium
Extrinsic Eye Muscles
the six skeletal muscles which attach to and move each eye
Auditory Ossicles
the three tiny bones serving as transmitters of vibrations and located within the middle ear: the malleus, incus, and stapes
Choroid
the vascular middle layer of the eye
Conjunctiva
thin, protective mucous membrane lining the eyelids and covering the anterior surface of the eye itself
Cornea
transparent anterior portion of the eyeball; part of the fibrous layer
Pharyngotympanic Tube
tube that connects the middle ear and the pharynx. Also called auditory tube, eustachian tube
_____ are one of the few types of neurons that can replace themselves in adult life. a. Olfactory receptors b. Taste buds c. Rods d. Cones
Olfactory receptors
Accessory glands that produce an oily secretion are the a. conjunctiva b. lacrimal glands c. tarsal glands
tarsal glands
Gustation
taste
Sensory impulses transmitted over the facial, glossopharyngeal, and vagus nerves are involved in the sensation of a. taste b. touch c. equilibrium d. small
taste
As we age, _____. a. the lens of the eye becomes increasingly elastic b. the clarity of the lens of the eye remains unchanged c. the number of cochlear hair cells in the ear increases d. the ability to detect high-pitched sounds diminishes
the ability to detect high-pitched sounds diminishes
Which of the following would NOT be found in the outer ear? a. modified sweat glands b. sebaceous glands c. hair d. pharyngotympanic tube
pharyngotympanic tube
The bleaching of the pigment refers to the _____. a. oxidation of vitamin A b. regeneration of cones at the end of the day c. presence of different types of opsin found in cones d. process of breaking down the retinal-opsin combinations that form the rhodopsin found in the rods and cones
process of breaking down the retinal-opsin combinations that form the rhodopsin found in the rods and cones
The tiny skeletal muscles associated with the ossicles of the middle ear function to _____. a. protect the hearing receptors from loud sounds b. increase the vibration of the tympanic membrane c. increase the vibration of the ossicles of the ear d. connect the ossicles to each other e. connect the ossicles to the oval window
protect the hearing receptors from loud sounds
Cranial nerve V is one of the nerves that carry the sensation of taste. a. True b. False
False
Aqueous Humor
watery fluid in the anterior segment of the eye
The blind spot of the eye is a. where more rods than cones are found b. where the macula lutea is located c. where only cones occur d. where the optic nerve leaves the eye
where the optic nerve leaves the eye
The optic disc on the retina is _____. a. where the optic nerve leaves the eye b. a dense collection of rod cells c. the same as the macula lutea d. the area of greatest visual acuity
where the optic nerve leaves the eye
Sclera
white opaque portion of the fibrous layer of the eyeball
Adaptation
(1) any change in structure or response to suit a new environment; (2) decline in the transmission of a sensory nerve when a receptor is stimulated continuously and without change in stimulus strength
Place the following events in the order in which they occur during sound transmission: 1. Tympanic membrane vibrates 2. Internal ear fluids are set in motion 3. Hearing receptors are stimulated 4. Ossicles of the ear vibrate 5. Auditory cortex is stimulated a. 2,1,5,3,4 b. 1,4,2,3,5 c. 1,2,4,3,5 d. 5,1,2,4,3
1,4,2,3,5
Choose the true statement. a. Vitreous humor is continuously produced and drained. b. Aqueous humor is formed in the embryo and lasts for a lifetime. c. Vitreous humor is located in the anterior segment of the eye. d. Aqueous humor supplies nutrients and oxygen to the lens and cornea.
Aqueous humor supplies nutrients and oxygen to the lens and cornea.
Impulses from the olfactory epithelium are sent to the brain via cranial nerve II. a. True b. False
False
Information from the balance receptors goes directly to the cerebral cortex. a. True b. False
False
Olfactory adaptation means that the olfactory receptors become more sensitive to the presence of an odor. a. True b. False
False
Sounds of low frequency cause the vibration of the basilar membrane closer to the oval window. Sounds of higher frequencies vibrate the oval window farther away from the oval window. a. True b. False
False
The area of the retina with the highest vision is called the optic disc. a. True b. False
False
The cornea is part of the vascular tunic. a. True b. False
False
The malleus in the middle ear is attached to the tympanic membrane on one end and to the oval window on the other end. a. True b. False
False
The posterior segment of the eyeball is filled with clear gel, called the aqueous humor. a. True b. False
False
The rods of the retina operate in bright light and provide high-acuity vision. a. True b. False
False
When the eyeballs rotate down, the inferior oblique muscle contracts. a. True b. False
False
Which of the following is true of static equilibrium receptors? a. Static equilibrium receptors are found in the semicircular canals of the ear. b. Static equilibrium receptors monitor the position of the head. c. Static equilibrium receptors are called cristae ampullares. d. Static equilibrium receptors can respond to rotational forces.
Static equilibrium receptors monitor the position of the head.
Choose the true statement about the cornea. a. The cornea is not well-supplied with nerve endings. b. The cornea lacks blood vessels. c. The cornea is continuous with the dura mater of the brain. d. The cornea is unable to regenerate.
The cornea lacks blood vessels.
Which of the following adaptations does NOT take place when one moves from a well-lit room to a dark room? a. The retina becomes less sensitive. b. Cones stop functioning. c. Initially, the rods are turned off. d. Rhodopsin accumulates.
The retina becomes less sensitive.
Olfactory receptor cells are neurons that undergo noticeable turnover throughout adult life. a. True b. False
True
The pharyngotympanic tube allows pressure equalization between the middle ear and the external environment. a. True b. False
True
The semicircular canals respond to rotational movements. a. True b. False
True
The sense of taste is heavily dependent on olfactory receptors. a. True b. False
True
The size of the pupil is dependent on the contraction of the muscles of the iris. a. True b. False
True
Choose the answer that shows the correct order of light transmission from the air to the retina. a. air, aqueous humor, lens, cornea, vitreous humor, retina b. air, cornea, lens, aqueous humor, vitreous humor, retina c. air, lens, cornea, vitreous humor, aqueous humor, retina d. air, cornea, aqueous humor, lens, vitreous humor, retina
air, cornea, aqueous humor, lens, vitreous humor, retina
Which of the following is important in maintaining the balance of the body? a. visual cues b. semicircular canals c. the saccule d. proprioceptors e. all of these
all of these
Which of the following is/are a part of the external ear? a. auricle b. tympanic cavity c. auditory ossicles d. semicircular canals
auricle
Which of the following is an INCORRECT match? a. bitter taste: elicited by metal ions b. umami taste: elicited by glutamate and aspartate c. sweet taste: elicited by alcohols d. sour taste: elicited by H+ ions in solution
bitter taste: elicited by metal ions
The conjunctival mucous membrane covers _____. a. only the outer corneal surface b. the inner surface of the eyelids only c. the inner surface of sclera d. both the inner surface of the eyelids and the visible portion of the sclera e. the whole outer surface of the sclera
both the inner surface of the eyelids and the visible portion of the sclera
The receptors for taste and smell are classified as _____. a. thermoreceptors b. chemoreceptors c. proprioceptors d. mechanoreceptors
chemoreceptors
Cataract
clouding of the eye's lens; often congenital or age-related
The organ of Corti is found in the _____. a. utricle b. saccule c. middle ear d. cochlear duct e. semicircular canal
cochlear duct
Which of the following is not a possible cause of conduction deafness? a. impacted cerumen b. middle ear infection c. cochlear nerve degeneration d. otosclerosis
cochlear nerve degeneration
Strabismus is caused by _____. a. alcohol intoxication b. congenital weakness of the extrinsic muscles of the eye c. retinal detachment d. paralysis of the intrinsic muscle of the eye
congenital weakness of the extrinsic muscles of the eye
Pink eye is caused by an infection that produces inflammation of the _____. a. cornea b. conjunctiva c. lacrimal gland d. tarsal glands
conjunctiva
The accessory structures of the eye do NOT include _____. a. eyebrows b. conjunctiva c. eyelids d. cornea e. lacrimal glands
cornea
Which sequence follows the correct passage of light entering the cornea? a. cornea, lens, anterior segment, posterior segment, lens b. cornea, pupil, posterior segment, lens, anterior segment c. cornea, lens, posterior segment, anterior segment, pupil d. cornea, pupil, anterior segment, posterior segment, lens e. cornea, anterior segment, pupil, lens, posterior segment
cornea, anterior segment, pupil, lens, posterior segment
Our eyes are best adapted for _____. a. color vision b. distant vision c. vision in bright sunlight d. close vision
distant vision
Diplopia
double vision
The pharyngotympanic tube _____. a. helps maintain balance b. carries sound to the eardrum c. equalizes air pressure between the middle ear and outside air d. amplifies sound waves
equalizes air pressure between the middle ear and outside air
Which of the following neurotransmitters is involved with hearing in the inner ear? a. glutamate b. norepinephrine c. dopamine d. acetylcholine
glutamate
Anosmia, an olfactory disorder is caused by _____. a. iron deficiency b. head injuries or the aftereffects of nasal cavity inflammation c. vagus nerve damage d. genetic disorders e. loss of gustatory epithelial cells
head injuries or the aftereffects of nasal cavity inflammation
Otoliths (ear stones) are a. a cause of deafness b. a type of hearing aid c. important in equilibrium d. the rock-hard petrous temporal bones
important in equilibrium
The near point of vision is the shortest _____. a. in a person over 50 years old b. in men c. when a person is 30-40 years old d. in children e. in women
in children
Where is the olfactory epithelium located? a. in the soft palate b. in the floor of the nasal cavity c. in the nostrils d. in the roof of the nasal cavity
in the roof of the nasal cavity
The receptors for sound reception and equilibrium are located in the _____. a. middle ear cavity b. middle and inner ear cavities c. outer, middle, and inner cavities d. inner ear cavity e. outer ear cavity
inner ear cavity
When a person cries, he or she tends to keep on wiping their dripping nose. The nose drips because _____. a. the nasal mucosa is sensitized to produce mucous into the nose b. lacrimal gland secretions wash the eyeball and drain into the lacrimal duct, which empties into the nasal cavity c. olfactory mucosa is sensitized to increase secretions into the nose d. the eyeball produces tears that drain into the lacrimal canal and then into the nose e. special secretory glands in the nose start to produce secretions into the nose
lacrimal gland secretions wash the eyeball and drain into the lacrimal duct, which empties into the nasal cavity
Ninety-nine percent of refractive problems in the eye are related to the _____. a. length of the eyeball b. strength of the ciliary muscles c. curvature of the lens d. curvature of the cornea
length of the eyeball
Which lies closest to the exact posterior pole of the eye? a. optic nerve b. optic disc c. macula lutea d. point of entry of central artery into the eye
macula lutea
Equilibrium receptors that report the position of the head in space relative to the pull of gravity are a. spiral organs b. maculae c. cristae ampullares d. otoliths
maculae
The horizontal movement of the eyeball toward the nose is the function of the _____. a. inferior rectus b. lateral rectus c. superior rectus d. superior rectus e. medial rectus
medial rectus
When focusing on a distant object, the lens is _____. a. more concave b. more convex c. more flattened d. not changed
more flattened
The structure that allows pressure in the middle ear to be equalized with atmospheric pressure is the a. pinna b. pharyngotympanic tube c. tympanic membrane d. oval window
pharyngotympanic tube
The _____ dilate the pupils of the eyes. a. inferior oblique muscles b. radial muscles c. medial rectus muscles d. circular muscles
radial muscles
Arrange the tunics of the wall of the eyeball in their correct sequence from inside out. a. choroid, retina, sclera b. retina, choroid, sclera c. choroid, sclera, retina d. sclera, choroid, retina e. retina, sclera, choroid
retina, choroid, sclera
Adjustment to low light conditions is primarily facilitated by changes in _____ concentration. a. rod b. vitamin A c. cone d. rhodopsin
rhodopsin
Dim light and peripheral vision receptors are called _____. a. foveae b. ganglion cells c. cones d. rods
rods
Retinitis pigmentosa is a disease of the _____. a. rods b. cones c. ciliary muscles d. lens
rods
The _____ is NOT a part of the vascular layer of the eye. a. sclera b. iris c. ciliary body d. choroid
sclera
Rotational movement of the head is monitored by receptors located in the _____. a. cochlear duct b. utricle c. cortex of the cerebrum d. saccule e. semicircular canals
semicircular canals
Seventy percent of the sensory receptors in the body involved with _____. a. taste b. sight c. hearing d. smell
sight
Which of the following are intrinsic eye muscles? a. superior rectus b. orbicularis oculi c. smooth muscles of the iris and ciliary body d. levator palpebrae superioris
smooth muscles of the iris and ciliary body
Ciliary glands are modified _____. a. sweat glands b. lacrimal glands c. salivary glands d. sebaceous glands
sweat glands
Which of the following types of stimulation results in an increase in the diameter of the pupil? a. somatic motor nerves b. parasympathetic nerves c. sympathetic nerves d. both the sympathetic and parasympathetic nerves e. damage to both autonomic nerves
sympathetic nerves
Ossicles
the three tiny bones serving as transmitters of vibrations and located within the middle ear: the malleus, incus, and stapes; see Auditory ossicles
As a rule, the only special sense not fully functional at birth is _____. a. smell b. hearing c. taste d. vision
vision
