Anatomy Chapter 15
Conduction deafness
One of the most common results of otitis media; can result from the fusion of the auditory ossicles; can result from impacted cerumen.
What term means that the lens can change shape so that the eye can focus on items either close at hand or far away?
accommodation
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 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.
Conduction deafness
A condition of deafness that may result from otosclerosis.
Glaucoma
A condition often leading to blindness due to increased intraocular pressure.
Night blindness
A condition that can result from a deficiency of vitamin A.
Tinnitus
A possible side effect of medications such as aspirin.
Otitis media
An inflammation of the lining of the middle ear.
Fovea centralis
Area of greatest visual acuity.
Taste is independent of smell.
False
Vision is fully developed at birth.
False
Aqueous humor
Helps maintain the intraocular pressure; located in the anterior part of the eye.
Sensorineural deafness
Loss of hearing resulting from prolonged exposure to high-intensity sounds.
Tinnitus, vertigo, and gradual hearing loss typify the disorder called ________.
Ménière's syndrome
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? What are the possible consequences of this condition? What is the function of the eyedrops?
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.
Which of the following is a characteristic of the lens?
The lens focuses light on the retina.
Retina
The sensory layer of the eye.
Lens
The structure most responsible for focusing light rays that enter the eye.
Which of the following is NOT a requirement for something to be tasted?
The tastant must contact the basal epithelial cells of the taste buds.
Odorants must be volatile to be smelled.
True
The function of the lens of the eye is to allow precise focusing of light on the retina.
True
The optic disc is the location where the optic nerve leaves the eyeball.
True
The photoreceptor cells are sensitive to damage from light.
True
When we move from darkness to bright light, retinal sensitivity is lost, but visual acuity is gained.
True
Bitter taste is elicited by ________.
alkaloids
Otosclerosis of which of these structures can result in conduction deafness?
auditory ossicles (malleus, incus, and stapes)
Receptors for hearing are located in the ________.
cochlea
Damage to which of these structures can result in sensorineural deafness?
cochlear nerve
Which of the following is not a possible cause of conduction deafness?
cochlear nerve degeneration
Damage to the medial rectus muscles would probably affect ________.
convergence
Light passes through the following structures in which order?
cornea, aqueous humor, lens, vitreous humor
Seventy percent of all sensory receptors are located in the ________.
eye
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 ________.
has no blood supply
Which region of the ear is involved in detection of both hearing and equilibrium?
internal ear
Dark adaptation ________.
involves accumulation of rhodopsin
The visible colored portion of the eye is the __________.
iris
What condition results when distant objects focus in front of the retina, rather than on it?
myopia
Most taste buds are located __________.
on the tongue
What part of the eye constitutes the blind spot?
optic disc
The major function of the conjunctiva is to __________.
produce mucus to prevent the eyes from drying out
Motion sickness seems to ________.
result from mismatch between visual and vestibular inputs
Which photoreceptors respond to very dim light?
rods
Olfactory cells and taste buds are normally stimulated by ________.
substances in solution
The blind spot of the eye is where ________.
the optic nerve leaves the eye
Ringing in the ears is called __________.
tinnitus
The boundary between the external and middle ear is the __________.
tympanic membrane
Which of the following taste sensations is incorrectly matched to the chemicals that produce it?
umami-triglycerides and fatty acids
The only special sense not fully functional at birth is the sense of ________.
vision
What is the main function of the rods in the eye?
vision in dim light