which of the following is a characteristic of the lens?

# which of the following is a characteristic of the lens?

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If a chalazion interferes with glandular secretion, the immediate outcome would be ______.friction on the anterior surface of the eye
Conjunctivitis does not directly affect ______.the conjunctival sac
When a person's cold is accompanied by "watery eyes," there is reduced flow of lacrimal fluid directly into the ______.lacrimal puncta
Which of the following nerves would you predict is NEVER involved in the development of strabismus?trigeminal (V)
If retinal detachment occurs in the macula lutea, one can predict that there would be a significant loss of ______.color vision
In glaucoma, damage occurs primarily to the ______.ganglion cells in the retina
In theory, cataracts could be prevented by invention of a treatment that would ______.increase diffusion rates within the lenses
Which of the following statements is true?Contraction of the ciliary muscles is required for hyperopic individuals to clearly see distant objects.
In a 30 year old man who has red-green color blindness, light having a wavelength of 530 nm is perceived as being green. This man ______.perceives that red light has a green color
Which of the following statements is FALSE?Nyctalopia affects vision in the fovea centralis, resulting in impaired vision.
If the optic chiasma is destroyed but the rest of the visual pathway to the brain is not damaged, the result would be ______.loss of peripheral vision on both the far right and far left sides of the visual field
The mucous membrane that lines the eyelids and is reflected over the anterior surface of the eyeball is the conjunctiva.True
The photoreceptor cells are sensitive to damage from light.True
The optic disc is the location where the optic nerve leaves the eyeball.True
The extrinsic eye muscle motor units contain only 8 to 12 muscle cells and in some cases as few as 2 or 3 muscle cells.True
The bending of light rays is called reflection.False
The anterior chamber of the eye is filled with vitreous humor.False
The neural layer of the retina prevents excessive scattering of light within the eye.False
Light passes through the entire thickness of the neural layer of the retina to excite the photoreceptors.True
Contraction of the ciliary muscle causes the lens to bend the light less.False
When we move from darkness to bright light, retinal sensitivity is lost, but visual acuity is gained.True
The function of the lens of the eye is to allow precise focusing of light on the retina.True
What is the main function of the rods in the eye?vision in dim light
What structure regulates the amount of light passing to the visual receptors of the eye?iris
Farsightedness is more properly called ________.hyperopia
Seventy percent of all sensory receptors are located in the ________.eye
Nerve fibers from the medial aspect of each eye ________.cross over to the opposite side at the chiasma
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
There are three layers of neurons in the retina. The axons of which of these neuron layers form the optic nerves?ganglion cells
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 ________.lateral geniculate body of the thalamus
What prevents the eyelids from sticking together when the eyes close?tarsal gland secretions
Conscious perception of vision probably reflects activity in the ________.occipital lobe of the cortex
In the visual pathways to the brain, the optic radiations project to the ________.primary visual cortex
Visual inputs to the ________ serve to synchronize biorhythms with natural light and dark.suprachiasmatic nucleus
The blind spot of the eye is where ________.the optic nerve leaves the eye
Which of the following could not be seen as one looks into the eye with an ophthalmoscope?optic chiasma
The cells of the retina in which action potentials are generated are the ________.ganglion cells
During dark adaptation ________.rhodopsin accumulates in the rods
Which of the following is true about light and vision?When we see the color of an object, all light is being absorbed by that object except for the color being experienced.
The tarsal plate of the eyelid ________.is connected to the levator palpebrae
Which of the following is true about photoreceptors?Rods absorb light throughout the visual spectrum but confer only gray tone vision.
The eye muscle that elevates and turns the eye laterally is the ________.inferior oblique
Light passes through the following structures in which order?cornea, aqueous humor, lens, vitreous humor
Visual processing in the thalamus does not contribute significantly to ________.night vision
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?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.
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?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.
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.
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. What is the rationale for pressing on the nasolacrimal duct?Applying gentle pressure to the nasolacrimal duct prevents the delivery of the drug to the nasal mucosa and general circulation, where it could affect heart rate.
Vitamin D needed by the photoreceptor cells is stored by the cells of the retina pigmented layer.False
Ciliary muscles are a type of skeletal muscle.False
Another name for the primary visual cortex is ________.striate cortex
Which statement about malnutrition-induced night blindness is most accurate?Vitamin supplements can reverse degenerative changes.
Dark adaptation ________.involves accumulation of rhodopsin
Damage to the medial rectus muscles would probably affect ________.convergence
Visible light fits between ________.UV and infrared
Which accessory eye structures function to produce the tears that cleanse and protect the eye?lacrimal glands
Which structure in the eye provides nutrition to all eye layers?choroid
What part of the eye constitutes the blind spot?optic disc
Which photoreceptors respond to very dim light?rods
Even though we have two eyes, why do we normally see only one image?Information from each eye goes to both hemispheres for processing.
The major function of the conjunctiva is to __________.produce mucus to prevent the eyes from drying out
Which of the following is NOTan accessory structure of the eye?retina
The visible colored portion of the eye is the __________.iris
Which of the following is a role of the vitreous humor?It supports the posterior surface of the lens.
Which of the following is a characteristic of the lens?The lens focuses light on the retina.
Choose the correctly paired terms.nyctalopia: night blindness
A stroke that affects the left visual cortex would lead to __________.blindness in the right half of the visual field
The receptors for smell are activated when __________.dissolved odorants bind to receptor proteins in the cilium membranes
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
Sour taste receptors are stimulated by hydrogen ions of acidic food substances.True
Odorants must be volatile to be smelled.True
Receptors for hearing are located in the ________.cochlea
Which of the follow types of neurons are replaced throughout adult life?olfactory receptor cells
Which of the following is true about gustatory receptors?Complete adaptation occurs in about one to five minutes.
Select the correct statement about olfaction.Some of the sensation of olfaction is actually one of pain.
Olfactory cells and taste buds are normally stimulated by ________.substances in solution
Which of the following is not a characteristic of olfactory receptor cells?They are unipolar neurons.
The receptor membranes of gustatory cells are ________.gustatory hairs
Bitter taste is elicited by ________.alkaloids
Which of the following taste sensations is incorrectly matched to the chemicals that produce it?umami-triglycerides and fatty acids
Which of the following is the basic taste quality responsible for the "beef taste" of steak?umami
Most taste buds are located __________.on the tongue
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.
The boundary between the external and middle ear is the __________.tympanic membrane
Ringing in the ears is called __________.tinnitus
Vision is fully developed at birth.False
What condition results when distant objects focus in front of the retina, rather than on it?myopia
During otitis media, large amounts of fluid or pus may accumulate in the tympanic cavity; the fluid is primarily ______.interstitial fluid
Which of the following would be the LEAST likely to be associated with the development of motion sickness?having a non-functional vestibular apparatus
The fluid contained within the membranous labyrinth is called perilymph.False
The structure that allows equalization of the pressure in the middle ear with that outside the body is the external auditory meatus.False
In order for sound to reach the spiral organ (of Corti), the auditory ossicles must vibrate the oval window and set the perilymph and endolymph in motion.True
Sound is generally perceived in the occipital lobe of the cerebral cortex.False
Without a functioning crista ampullaris, the semicircular canals would not function.True
Theoretically, an individual born without a middle ear would be able to hear by bone conduction with a hearing aid.True
The receptor for static equilibrium is the ________.macula
Which of the following structures is not part of the external ear?pharyngotympanic tube
The oval window is connected directly to which passageway?scala vestibuli
As sound levels increase in the spiral organ (of Corti), ________.outer hair cells stiffen the basilar membrane
What is a modiolus?a bone pillar in the center of the cochlea
Information from balance receptors goes directly to the ________.brain stem reflex centers
Motion sickness seems to ________.result from mismatch between visual and vestibular inputs
An essential part of the maculae involved in static equilibrium is (are) the ________.otoliths
Select the correct statement about equilibrium.Cristae respond to angular acceleration and deceleration.
Which statement about sound localization is not true?It requires processing at the cortical level.
Which of the following is not a possible cause of conduction deafness?cochlear nerve degeneration
Ceruminous glands are ________.modified apocrine sweat glands
Static equilibrium involves linear acceleration as well as changes in head rotation.false
Hair cells in the spiral organ of the ear are never replaced.False
The quality of a sound is based on the atmospheric pressure at the time the sound is generated.False
Which pairing of terms is incorrectly related?frequency of sound waves: loudness of the sound
Tinnitus, vertigo, and gradual hearing loss typify the disorder called ________.Mnire's syndrome
Which middle ear ossicle is attached to, and transmits vibratory motion to, the oval window?stapes
Which of the following is the receptor organ for hearing?spiral organ (of Corti)
What is the vestibular apparatus?the equilibrium receptors in the semicircular canals and vestibule
Which of the following correctly matches the equilibrium receptor to the type of equilibrium it monitors?maculae/static equilibrium
Where are equilibrium receptors located?in the semicircular canals and in the vestibule of the ear
There are __________ auditory ossicles in the ear.three
The final step in perceiving sound is __________.the auditory cortex is stimulated
The receptor organ for hearing is the __________.spiral organ (of Corti)
The distance between two consecutive wave crests is the __________.wavelength
Which of the following is true of receptors for dynamic equilibrium?The receptors for dynamic equilibrium respond to rotational forces.
Information from balance (equilibrium) receptors goes directly to __________.the brain stem
Choose the FALSE statement about the olfactory epithelium.It is made of simple squamous epithelium.
Eye color is determined by the amount of brown pigment present in the iris.True
Rubella infection during early pregnancy may cause damage to the embryo's ______.All of the listed responses are correct.
Congenital sensorineural deafness most commonly involves damage to ______.the cochlear hair cells
\ Most newborns ________.often use only one eye at a time
The first vestiges of eyes in the embryo are called ________.optic vesicles
The only special sense not fully functional at birth is the sense of ________.vision
Taste is independent of smell.False
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