Mastering A&P Chapter 16

Identify the letter that indicates the portion of the fibrous layer known as the sclera.

A

Identify the letter that indicates the structure that is the boundary between the external and middle ear.

A

Identify the fluid filled space between the cornea and iris.

Anterior chamber

Identify the letter that indicates the middle ear ossicle that is known as the stirrup.

B

Identify the letter that indicates the region of the retina that contains only cones and provides maximal visual acuity.

B

Identify the letter that indicates the ciliary body.

C

Identify the letter that indicates the structure that contains receptors for rotational acceleration.

C

Melanin-containing layer of the eye's vascular tunic.

Choroid

Blindness caused by glaucoma is the result of increased pressure in the anterior segment of the eye and compression of the optic nerve. What is the correct pathway for aqueous humor production and drainage into the anterior segment of the eye?

Ciliary processes, posterior chamber, pupil, anterior chamber, scleral venous sinus

Identify the letter that indicates the structure that is called the cochlea.

D

Identify the letter that indicates the transparent portion of the fibrous layer.

D

Identify the letter that indicates the anterior segment, which is filled with aqueous humor.

E

Identify the letter that indicates the structure that is important in equalizing air pressure on both sides of the eardrum.

E

Drag each label into the appropriate bin to indicate to which layer of the eye each structure belongs.

FIBROUS LAYER sclera, cornea VASCULAR LAYER Choroid, ciliary body, iris, pupil, cililary zonule INNER LAYER retina, optic nerve, fovea centralis, macula lutea, ora serrata, optic disc

Lacrimal fluid is produced by the lacrimal sac in the medial canthus of the eye.

False

Light entering the eye passes first to the rod and cone cells, then to bipolar cells, and finally to ganglion cells adjacent to the pigmented retina.

False

The iris divides the eye into the anterior and posterior segments.

False

The pupil can adjust its size independent of the iris.

False

The superior oblique muscle of the eye enables the eye to look upward and laterally.

False

The ________ muscle allows your left eye to look up and to the left.

Inferior oblique

The __________ muscle depresses the eye and turns it medially.

Inferior rectus

Identify the structure that regulates the amount of light entering the posterior segment of the eye.

Iris

Which is true about a retinal detachment?

It can result from a blow to the eye.

Which of these statements concerning vitreous humor is FALSE?

It is renewed continuously.

Why is the sense of touch not considered a "special sense"?

Its receptors are widespread throughout the body.

The visual pathway describes the route that light takes and the cells it activates on the way to the region of the brain where it is processed. Correctly construct the visual pathway.

LIGHT ENTERING THROUGH CORNEA lens cones and rods bipolar cells ganglion cells thalamus PRIMARY VISUAL CORTEX OF OCCIPITAL LOBE

Lateral movement of the eye is controlled by the _________ muscle.

Lateral rectus

Lila's pediatrician covered her right eye with a patch for several months to try and strengthen the muscles of her wandering left eye. Her strabismus only improved slightly, so he suspected nerve damage. He told Lila's parents that the condition was likely sixth nerve palsy. Which extrinsic eye muscle was not being properly innervated?

Lateral rectus

Correctly sort the different special senses into the box that matches them with the type of receptor cell that allows for that sense.

MECHANORECEPTOR hearing, equilibrium PHOTORECEPTOR vision CHEMORECEPTOR taste, smell

Medial movement of the eye is controlled by the ____________ muscle.

Medial rectus

A 58-year-old gentleman noted that he was having problems reading cross-word puzzles. The letters appeared fuzzy and he guessed that he needed reading glasses. What condition does he have?

Presbyopia

In describing the distribution of photoreceptors on the retina, which of the following statements is true?

Rod cells are more numerous and more light sensitive than cones, which allows for gray, fuzzy vision in dim light.

The ________ muscle allows your left eye to look down and to the left.

Superior oblique

The _____________ muscle elevates the eye and turns it medially.

Superior rectus

What is strabismus?

The affected eye is turned medially or laterally with respect to the normal eye; results from weakness or paralysis of extrinsic eye muscles.

Identify the areas that are filled with aqueous humor.

The anterior and posterior chambers

When the lens of the eye bulges for close vision, which of the following happens?

The ciliary muscles contract.

Why do corneal transplants have minimal risk of rejection?

The cornea is avascular and has minimal exposure to the recipient's immune system.

What layer of the retina undergoes age-related degeneration and is the primary cause of the condition.

The pigmented layer

You are listening to music on your iPod at a very loud volume. What happens in your middle ear to protect the hearing receptors in your inner ear?

The tensor tympani and stapedius muscles contract reflexively.

What is the function of the outer hair cells in the spiral organ (organ of Corti)?

They are involved with actively tuning the cochlea and amplifying the signal.

The cone-filled region of the retina surrounding the fovea centralis is called the macula lutea.

True

Both the choroid and the retina __________.

absorb light and prevent it from scattering within the eye

What axons decussate in the optic chiasma?

axons from the medial half of each eye

In hyperopic (farsighted) eyes, diverging light rays from nearby objects cause the focal point to occur __________, resulting in __________ objects to appear blurry.

behind the retina / nearby

Which of the following lies closest to the anterior pole of the eye?

center of the cornea

Which response does NOT occur in the eye to aid in viewing near objects?

change in shape of the cornea

Transparent mucous membrane covering the inner surface of the eyelid.

conjunctiva

Transparent structure of the eye containing regularly aligned collagen fibers.

cornea

Which of the following would not be associated with strabismus?

damage to the optic nerve

Which cranial nerve does not innervate the extrinsic eye muscles?

facial

There are three layers of neurons in the retina. Which of the following neurons have axons that form the optic nerves?

ganglion cells

Ordinarily, it is not possible to transplant tissues from one person to another without rejection, yet corneas can be transplanted with impunity. This is because the cornea

has no blood supply, except around the periphery.

Farsightedness is more properly called

hyperopia

Hyperopia and presbyopia may have some features in common, but a key difference between these two conditions is that

in hyperopia the lens can accommodate, but in presbyopia it cannot.

Which of these extrinsic eye muscles depresses the eye and turns it medially?

inferior rectus

The superior oblique muscle turns the eye both laterally and

inferiorly

Where do tears drain?

into the nasal cavity

Each of the following structures participates in bending of light entering the eye except the

iris

The modiolus __________.

is a pillar of bone shaped like a screw whose tip lies at the apex of the cochlea

What structure is handled by an "eye bank"?

just the cornea

The eyelids house all of the following except the

lacrimal sac

The first "way station" (relay nucleus) in the visual pathway from the eye, after there has been partial crossover of the fibers in the optic chiasma, is the

lateral geniculate nucleus.

Accessory structures of the eye--lateral view

left image

Anatomy of the cochlea

left image

Clouding of which of the following structures would lead to a clinical condition known as a cataract?

lens

Which structure divides the internal chamber of the eye into anterior and posterior segments?

lens

The muscle that opens the eye is the

levator palpebrae superioris.

Odors may elicits a variety of emotions if these impulses are relayed through the __________.

limbic system

Which portion of ear contains ear ossicles?

middle

Nearsightedness is more properly called

myopia

The center for vision in the cerebral cortex is located in the

occipital lobe.

Damage to which cranial nerve would be suspected if a light aimed at the eye did not initiate the pupillary light reflex to cause pupil constriction?

oculomotor nerve

The ora serrata is a

part of the retina

Nerve axons from the lateral portion of each retina

pass posteriorly without crossing over at the chiasma.

The equilibrium pathway transmits most of its information to lower brain centers because the __________.

pathway responds to loss of balance and must be rapid and reflexive to prevent injury

What structure regulates the amount of light passing to the visual receptors of the eye?

pupil

Detailed structure of the spiral organ

right image

What is the specific location of the inner and outer hair cells for hearing?

scala media (cochlear duct)

Which portion of the eye is covered by conjunctiva?

sclera

In addition to sending visual information to the primary visual cortex, some axons from the optic tracts go to the __________.

suprachiasmatic nucleus in the hypothalamus to regulate daily biorhythms

The oil component found in tears is produced by the

tarsal glands.

The scala tympani __________.

terminates at the round window at the base of the cochlea and is filled with perilymph

In which region of the brain do the axons of the optic tract synapse?

thalamus

Which of the following areas has the highest concentration of cones?

the fovea centralis

Which of the following structures in the eye are pigmented?

the retina

Another name for the ciliary zonule is

the suspensory ligament of the lens.

Olfactory sensory neurons __________.

undergo replacement throughout life

Fluid filling the posterior segment of the eye.

vitreous humor