Q&A Hero

Q: The most common form of color blindness is deuteranopia, which is congenital absence of the ____ gene. M B. L C. S

Q: The M and L cones are coded on chromosome 7 making the lack of the M and L photopsins more prevalent in females.

Q: Each cone communicates with only one ganglion cell while many rods communicate with one ganglion cell.

Q: The fovea centralis contains only rods.

Q: Those who suffer from macular degeneration lose clarity of vision provided by the fovea.

Q: The wavelengths of light a photoreceptor responds to is determined by the opsin in the photoreceptor.

Q: Different layers of the __________________ analyze input from cones (and rods) differently such that one layer can add input from L and M cones to obtain information about light intensity, while another could subtract such input to obtain red-green color information. A. hypothalamus B. superior colliculi C. lateral geniculate nucleus D. red nucleus

Q: Light energy will cause all-trans retinal to convert to the 11-cis form which dissociates from opsin to eventually create the nerve impulse.

Q: Photoreceptors have the enzyme to re-isomerize the all-trans retinal back to the 11-cis form.

Q: Which cells have the ability to re-isomerize the all-trans retinal back to the 11-cis form? A. photoreceptor cells B. ganglion cells C. pigment epithelial cells D. bipolar cells

Q: What is the name of the process that re-isomerizes the all-trans retinal back to the 11-cis form? A. dark adaptation B. visual cycle of retinal C. bleaching reaction D. dark current

Q: Retinaldehyde (retinal) is derived from A. vitamin A. B. vitamin C. C. opsin. D. vitamin D

Q: The generator potential produced in photoreceptors is a hyperpolarization.

Q: Inhibiting phosphodiesterase would cause the photoreceptor to undergo A. hyperpolarization. B. depolarization. C. repolarization. D. EPSPs.

Q: In the absence of light, there is movement of Na+ in the photoreceptors causing a depolarization. This is called the A. dark adaptation. B. visual cycle of retinal. C. bleaching reaction. D. dark current.

Q: In the dark, the photoreceptors release an inhibitory neurotransmitter that prohibits bipolar neurons from exciting ganglion neurons.

Q: What causes cGMP to convert to GMP and close Na+ channels in a photoreceptor? A. dark current B. light C. darkness D. opsin

Q: What type of G-proteins are associated with the visual cycle? A. transducins B. gustducins C. roducins D. None apply.

Q: Only absorbed light can produce photochemical reactions that result in vision.

Q: Dominant retinitis pigmentosa is characterized by A. deterioration of the striate cortex. B. degeneration of photoreceptors. C. degeneration of the optic nerve. D. degeneration of the cornea.

Q: What color of light is best absorbed by rods? A. blue-green B. red C. yellow D. purple

Q: The optic nerve is formed from fibers of A. rods and cones. B. bipolar cells. C. amacrine cells. D. ganglion cells.

Q: Within the eye, electrical impulses pass from A. photoreceptors to ganglion cells to bipolar cells. B. ganglion cells to bipolar cells to photoreceptors. C. photoreceptors to bipolar cells to ganglion cells. D. bipolar cells to photoreceptors to ganglion cells.

Q: Rods and cones face to the front of the eyeball (toward the incoming light).

Q: The tip region of the photoreceptor cells are removed by cells of the retinal pigment epithelium by A. apoptosis. B. phagocytosis. C. opsin. D. the bleaching reaction.

Q: Which of the following is NOT true of the functions of the pigment epithelium of the retina? A. absorption of scattered light B. stabilize ion composition surrounding the photoreceptors C. creating the dark current of the photoreceptors D. delivery of nutrients to the photoreceptors

Q: Bleaching induces conformational changes in both retinal and the associated opsin.

Q: Myopia is corrected with concave lenses.

Q: Myopia generally occurs when the A. eyeball is too short. B. eyeball is too long. C. lens is uneven. D. cornea is uneven.

Q: Loss of accommodation with age is A. astigmatism. B. myopia. C. hyperopia. D. presbyopia.

Q: Hyperopia is corrected with a concave lens.

Q: What condition occurs when the eyeball is too short and the focal point appears behind the eyeball? A. astigmatism B. myopia C. hyperopia D. presbyopia

Q: ______________ occurs when there is significant asymmetry of the cornea and/or lens. A. Myopia B. Hyperopia C. Astigmatism D. Presbyopia

Q: An individual with astigmatism would have their vision corrected by A. a convex lens. B. a concave lens. C. cylindrical lens. D. a magnifying lens.

Q: What new procedure is used by many people to correct refractive problems? A. lens replacement B. LASIK C. corrective lenses D. refractometry

Q: LASIK surgery can correct for all types of refractive problems.

Q: _____________ in the retina connect photoreceptors and ganglion cells. A. Horizontal cells B. Retinal epithelium C. Amacrine cells D. Bipolar cells

Q: When an object is more than 20 feet from the eyes, A. the ciliary muscle relaxes. B. there is tension on the zonular fibers of the suspensory ligament. C. the lens is pulled and flattened. D. All apply.

Q: Being able to distinguish separate trees in the forest is an example of the resolving power of visual acuity.

Q: The bending of light as it passes through different media is called A. accommodation. B. visual acuity. C. refraction. D. astigmatism.

Q: The letter ' would be projected onto the retina as A. B. C. D.

Q: The aggregation of cystallin proteins in the lens produces A. glaucoma. B. cataracts. C. astigmatism. D. myopia.

Q: Light is refracted the most by the A. cornea. B. aqueous humor. C. lens. D. vitreous humor.

Q: Contraction of ciliary muscles allows the lens to become thicker.

Q: The near point of vision decreases with increasing age.

Q: Accommodation would occur when A. the muscles of the ciliary body contract. B. the zonular fibers become taut. C. objects move further away from the eye. D. the lateral rectus muscle contracts.

Q: Pupil diameter would be increased by A. contraction of the circular muscles. B. contraction of the ciliary body. C. contraction of the superior rectus muscle. D. contraction of the radial muscles.

Q: The outermost layer of the eyeball is the A. choroid. B. retina. C. sclera. D. lens.

Q: What is found in the anterior cavity of the eyeball? A. aqueous humor B. blood C. vitreous humor D. pigment

Q: What is found in the posterior cavity of the eyeball? A. aqueous humor B. blood C. vitreous humor D. pigment

Q: What structure holds the lens in place? A. canal of Schlemm B. suspensory ligament C. choroid D. iris

Q: The lens is clear with no blood because it is made of dead cells.

Q: What area of the retina has no photoreceptors? A. fovea centralis B. macula C. optic disc D. None apply.

Q: Destroying the ciliary body would prevent the _____________ from receiving nutrients. A. cornea sclera B. iris C. pupil D. lens and cornea

Q: Sympathetic stimulation is responsible for pupil _____________ in _________ light. A. dilation, bright B. dilation, dim C. constriction, bright D. constriction, dim

Q: Long term blockage of the canal of Schlemm can induce A. glaucoma. B. cataracts. C. macular degeneration. D. detached retina.

Q: Which of the following organs HAS dual ANS innervation? A. arrector pili muscles B. adrenal medulla C. iris D. most blood vessels

Q: The pons is directly involved in regulating the autonomic nervous system.

Q: The medulla oblongata controls many autonomic activities through the A. paravertebral ganglia. B. vagus nerve. C. collateral ganglia. D. splanchnic nerves.

Q: The ____________________ can control autonomic function such that under some emotional states, autonomically controlled visceral reactions like blushing, fainting, etc., can occur. A. reticular activating system B. medulla oblongata C. limbic system D. cerebrum

Q: The major regulatory center of the autonomic system is, according to many scientists, the ______________ since this brain region has functions, such as control of body temperature, that require appropriate activation of sympathetic and parasympathetic nerves. A. hypothalamus B. thalamus C. midbrain D. cerebrum

Q: Visceral reactions which accompany emotional states are due to activation of the autonomic nervous system by the A. limbic system. B. cerebral cortex. C. cerebellum. D. pons.

Q: Which part of the brain helps to regulate the ANS actions from the medulla during motion sickness? A. hypothalamus B. limbic system C. cerebrum D. cerebellum

Q: It is impossible to consciously control autonomic activities.

Q: Studies have indicated that aging is associated with increased levels of parasympathetic activity and tone.

Q: A cochlear implant may help someone with conduction deafness.

Q: Which of the following organs is dually innervated? A. adrenal medulla B. arrector pili muscles in the skin C. urinary bladder D. most blood vessels

Q: Nonshivering thermogenesis requires the A. somatic nervous system. B. sympathoadrenal system. C. parasympathetic system. D. limbic system.

Q: Bradykinin stimulates A. surface blood vessel dilation. B. surface blood vessel constriction. C. salivary gland secretion. D. cerebral artery vasodilation.

Q: Atropine would A. block the release of epinephrine from the adrenal medulla. B. block constriction of the pupil. C. stimulate skeletal muscle contraction. D. facilitate near vision.

Q: Muscarinic antagonists stimulate _____________ pupillary diameter. increased B. decreased C. no change in

Q: Nitric oxide is made when Ca2+ influx into the axon terminal indirectly activates nitric oxide synthetase, which forms nitric oxide from the amino acid L- A. lysine. B. serine. C. arginine. D. asparagine.

Q: Postganglionic axons which do not secrete either catecholamines or acetylcholine may secrete A. ATP. B. nitric oxide. C. vasoactive intestinal peptide. D. All apply.

Q: A defect in nitric oxide synthetase gene may result in reduced ___________ of cerebral arteries since nitric oxide production would be impaired. A. vasoconstriction vasodilation

Q: If the effects of sympathetic and parasympathetic stimulation are similar, then the effects would be cooperative.

Q: Which of the following is NOT an example of the cooperative effects of the sympathetic and parasympathetic divisions of the ANS? A. micturition B. male sexual function C. saliva production D. sweating

Q: Beta-adrenergic receptors stimulate the production of cAMP.

Q: Alpha-1-adrenergic receptors are mediated by A. cAMP. B. Ca2+. C. K+. D. Na+.

Q: Adrenergic receptors are found on the surface of postganglionic sympathetic neurons.

Q: Nicotinic agonists would bind cholinergic receptors on preganglionic autonomic neurons.