Chapter 15 Homework

A) convergence

Convergence is the medial rotation of the eyeballs by the medial rectus muscles so that we can fixate on a close object.

What term refers to the eye’s moving medially to track items close at hand? A) convergence B) constriction C) accommodation D) refraction

C) damage to the hair cells near the oval window in the cochlear duct

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) an overgrowth of bony tissue, fusing the ossicles together B) middle ear infection C) damage to the hair cells near the oval window in the cochlear duct D) a perforated tympanic membrane

Eyeball

C) the white of the eye

The sclera is the outer, tough, protective layer of the eyeball that is white in color. The bulbar conjunctival membrane is the membrane that sits on top of the sclera at the anterior of the eye, but it is not a structural part of the sclera. If the bulbar conjunctiva membrane becomes inflamed, it may affect the sclera, however as it is not a structural part of the sclera, this would be an indirect affect. Inflammation of the sclera is termed scleritis.

Conjunctivitis does not directly affect ______. A) the superior palpebra B) the inferior palpebra C) the white of the eye D) the conjunctival sac

C) ciliary body

The ciliary body contains capillaries that filter fluid from blood to form the aqueous humor.

Aqueous humor forms during capillary filtration in the __________? A) iris B) scleral venous sinus C) ciliary body D) lens

Surface Anatomy of Right Eye

A) has no blood supply

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 blood supply B) is not a living tissue C) has no nerve supply D) does not contain connective tissue

C) fibrous

The fibrous layer includes the tough sclera (the "white" of the eye) as well as the transparent cornea.

Which layer of the eye is indicated by letter A? A) vascular B) neural C) fibrous

C) iris

The iris, the visible colored part of the eye, is the most anterior portion of the vascular layer of the eye, and either dilates or constricts to control how much light enters the posterior chamber.

What portion of the eye controls how much light passes into the posterior chamber? A) sclera B) cornea C) iris D) pupil

C) The condition is glaucoma. Blindness could result if not treated or caught early. The eyedrops increase the rate of aqueous humor drainage or decrease its production.

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, eyedrops would be merited. What is wrong with Roger’s eyes? What are the possible consequences of this condition? What is the function of the eyedrops? A) The condition is myopia. The increased pressure is causing the lens to bend, and will result in the need to wear glasses or contact lenses. The eyedrops will decrease the pressure, and in time he will not need to wear glasses or contact lenses. B) The condition is diplopia. Double vision, blurred vision, and loss of color perception may occur. The eyedrops will decrease the internal pressure, relaxing the lens and restoring normal vision. C) The condition is glaucoma. Blindness could result if not treated or caught early. The eyedrops increase the rate of aqueous humor drainage or decrease its production. D) The condition is a cataract. Blindness could result if not treated. The eyedrops will gradually remove the clouding of the lens, restoring vision. E) The condition is retinal detachment. The increased pressure has caused the retina to detach from the choroid, resulting in light flashes and spots in the vision. The eyedrops will decrease the internal pressure. What portion of the eye controls how much light passes into the posterior chamber?

A) Susie has strabismus. The doctor’s recommendations are for eye exercises and/or placing a patch over the unaffected eye; in severe cases, the condition may require surgery.

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? A) Susie has strabismus. The doctor’s recommendations are for eye exercises and/or placing a patch over the unaffected eye; in severe cases, the condition may require surgery. B) Susie has diplopia. The doctor’s recommendations are for glasses or contact lenses, or laser surgery to correct the problem. C) Susie has astigmatism. The doctor’s recommendations are for glasses or contact lenses, or laser surgery to correct the problem. D) Susie has astigmatism. The doctor’s recommendations are for eye exercises and/or placing a patch over the affected eye; in severe cases, the condition may require surgery. Susie has strabismus. The doctor’s recommendations are for eye exercises and/or placing a patch over the affected eye; in severe cases, the condition may require surgery.

C

The inner layer (retina) contains both the pigmented layer and the neural layer.

Identify the layer that contains both a single-celled pigmented layer and a neural layer. A B C D

A) emmetropic

Emmetropic eyes are considered normal. They are the right length (anterior/posterior) to place properly focused images on the retina.

This image best illustrates an eyeball that is __________. A) emmetropic B) myopic C) hyperopic D) inverted

C

The cone cells are photoreceptor cells that require brighter light, By differentiating input from three different types of cones, the brain can differentiate color and high resolution.

Identify the type of neuronal cell that detects bright light and provides high-resolution color vision. A B C D

D

The cochlear nerve carries information about hearing from the hair cells of the cochlea to the auditory cortex. Damage at any point along this pathway can lead to sensorineural deafness.

Damage to which of these structures can result in sensorineural deafness? A B C D

C) contract the ciliary body

Contracting the ciliary body would allow the lens to recoil and bulge, which would enhance focus on close objects.

During close vision, what actions must the eye take to bring an object into focus? A) change the curvature of the cornea B) relax the ciliary body C) contract the ciliary body D) dilate the pupil

Eye and Accessory Structures

C) inferior rectus

The inferior rectus originates from the common tendinous ring at the back of the orbit and inserts into the inferior surface of the eye.

Name the muscle at D. A) superior oblique B) medial rectus C) inferior rectus D) lateral rectus

A) ciliary body: focus the pupil

The ciliary body does have a muscular complex; however, it acts to change the shape of the lens to focus an image on the retina.

Which structure is NOT matched with its function? A) ciliary body: focus the pupil B) retina: senses light C) iris: allow light into eye D) choroid: vascular layer

D) hyperopia

The ability to clearly see objects at a distance but not close up is properly called ________. A) myopia B) hypopia C) presbyopia D) hyperopia

A

The semicircular canals house the receptors for sensing rotational (angular) motion of the head.

Which part of the inner ear houses receptors for rotational (angular) movement of the head? A B C D

A

Ganglion cells are last in the transmission pathway seen here. Their role is to transmit the visual signals to the thalamus.

Identify the neuron that is last in the transmission pathway of light information, given the cells shown in this image. A B C D

B

Letter B includes the air-filled chamber containing the malleus, incus, and stapes. An infection here would be called otitis media.

A middle ear infection (otitis media) would be located in which region? A B C

A) modified apocrine sweat glands

Ceruminous glands are ________. A) modified apocrine sweat glands B) saliva glands found at the base of the tongue C) glands found in the lateral corners of your eye D) modified taste buds

C) malleus, incus, stapes

What are the names of the bones at A, in order from left to right? A) incus, stapes, malleus B) malleus, stapes, incus C) malleus, incus, stapes D) stapes, malleus, incus

C

The internal ear possesses the structures for both hearing and equilibrium sensing.

Which letter indicates structures involved in detection of BOTH hearing and equilibrium? A B C D

D

The cochlea houses the spiral organ (of Corti), which senses hearing.

What part of the inner ear houses the receptor organ of hearing, the spiral organ (organ of Corti)? A B C D

A) color vision

The macula lutea (yellow spot) is an area of the retina that is lateral to the blind spot. It is made up almost entirely of cones, specialized photoreceptor cells that help us see color.

If retinal detachment occurs in the macula lutea, one can predict that there would be a significant loss of ______. A) color vision B) dim-light vision C) vision of objects in the peripheral regions of the D) visual field E) All of the listed responses are correct.

B

The choroid is the part of the vascular layer that lies posterior to the cornea’s edge and under the sclera.

Identify the choroid. A B C D

A) iris

What structure regulates the amount of light passing to the visual receptors of the eye? A) iris B) aqueous humor C) lens D) cornea

A) A cataract is a clouding of the lens. Some cataracts are congenital, but most are due to age-related hardening and thickening of the lens, diabetes mellitus, or exposure to UV rays over time. The lens can be removed and replaced with an artificial lens.

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 cataracts, how do they occur, and how are they treated? A) A cataract is a clouding of the lens. Some cataracts are congenital, but most are due to age-related hardening and thickening of the lens, diabetes mellitus, or exposure to UV rays over time. The lens can be removed and replaced with an artificial lens. B) A cataract is increased intraocular pressure. This occurs when drainage of the aqueous humor is blocked. They are treated with eyedrops that increase the rate of aqueous humor drainage or decrease its production. C) A cataract occurs when there are unequal curvatures in different parts of the cornea or lens. This is a congenital condition. Specially ground lenses or laser surgical procedures are used to correct this problem. D) A cataract is a clouding of the cornea. Some cataracts are congenital, but most are due to age-related hardening and thickening of the lens, diabetes mellitus, or exposure to UV rays over time. A corneal transplant can be performed to replace the damaged cornea.

B) The lens focuses light on the retina.

The lens is a biconvex, transparent, flexible structure that can change shape to precisely focus light on the retina. It is enclosed in a thin, elastic capsule and held in place just posterior to the iris by the ciliary zonule. Like the cornea, the lens is avascular; blood vessels interfere with transparency.

Which of the following is a characteristic of the lens? A) The lens of the human eye has a concave shape. B) The lens focuses light on the retina. C) In a healthy eye, the lens will be opaque. D) The lens is vascularized.

A) right eye: inferior oblique left eye: superior rectus

The right eye requires both elevation and lateral movement. The inferior oblique would accomplish both of these. The left eye requires both elevation and medial movement. The superior rectus, because it approaches the eye from the medial side, turns the eye medially as it elevates.

You want to look up and to your right. Which extrinsic eye muscles would be the most active in each eye? A) right eye: inferior oblique left eye: superior rectus B) right eye: superior rectus left eye: inferior oblique C) right eye: superior oblique left eye: superior rectus D) right eye: superior rectus left eye: superior rectus

A) there are no photoreceptors where the optic nerve leaves the eye

The blind spot of the eye is caused by ________. A) there are no photoreceptors where the optic nerve leaves the eye B) the macula lutea interrupts the nerve pathway C) more rods than cones within the retina D) an absents of cones in the foveae

Eye Muscles

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