Exam 3: CH14 – Flashcards

In a person who is color blind, which of the following would you most expect to see? Select one: a. absence of green or red cones in their foveae b.an inability to regenerate 11-cis-retinal after bleaching c. a loss of functions in the rods of their retina d.a loss of their peripheral vision

Area of greatest visual acuity. Select one: a. Lens b. Retina c.Aqueous humor d.Fovea centralis e. Cornea

Humans can see several thousand shades of color but have cone photoreceptors that are sensitive to only three (perhaps four) wavelengths of light. What is the best explanation for why we see so many colors? Select one: a.Color perception is dependent on the millions of rods as well as cone photoreceptors. b.Color perception is achieved by activation of various combinations between the three cone types. c.Shades of color are purely psychological and learned by association with age, infants only seeing in black and white. Incorrect d. Colors are added and enhanced in the primary visual cortex of the brain.

Sympathetic fibers innervating the iris of the eye cause which response? Select one: a.Rapid blinking b.Papillary decrease c. Dilation d. Constriction

Photoreceptors are modified neurons. However, they differ from most neurons in the fact that ________. Select one: a. photoreceptors do not have fluctuations in membrane potential b.photoreceptors do not release neurotransmitters c.photoreceptors are sensitive to energy changes in the external environment d. photoreceptors will hyperpolarize when stimulated

Overlap in the visual fields of our eyes ________. Select one: a.is essentially a waste of brain processing for what is essentially the same image b. gives us higher visual acuity for small detail by doubling the number of photoreceptors that are being stimulated c.leaves a blind spot anterior to the nose and in the lateral fields of vision d.allows us to subconsciously estimate the distance of objects based on the different angles the image strikes our two retinas

Of the following senses, which accounts for the majority of sensory receptors in the body? Select one: a. Gustation b. Olfaction c.Vision d. Hearing

In order to turn the eye straight down, the actions of the __________ muscle(s) is (are) required. Select one: a.superior rectus and superior oblique b.inferior rectus c.inferior rectus and superior oblique d.inferior rectus and lateral rectus

The cornea is actually part of the __________ layer of the eye. Select one: a. sensory b. vascular c. scleral d. fibrous

Color vision has much greater resolution than night vision (vision that is mostly in shades of gray). Which of the following is the best explanation for why this is so? Select one: a. A single cone photoreceptor often connects to a single bipolar cell and a single ganglion cell while as many as 100 rods will converge to a single ganglion cell. b. There are several types of cone photoreceptors, each of which enrich the clarity and resolution of vision. c. A larger proportion of the brain's visual cortex is active during the day when our cone photo receptors are most active. d. There are many more cone photoreceptors in the eye than rod photoreceptors.

Which of the following is the best explanation of why it is difficult to discriminate the color of an object at night? Select one: a. Cones come in three types, each sensitive to different wavelengths of light. b.The foveae are densely packed with cones. c. As many as 100 cones may converge on one ganglion cell d.Rods contain a single kind of visual pigment.

The structure most responsible for focusing light rays that enter the eye. Select one: a. Retina b.Fovea centralis c. Cornea d. Lens e.Aqueous humor

Select the statement below that is not true with regards to the process of light adaptation. Select one: a.Visual acuity is diminished. b.The activity of rods is reduced by rapid bleaching of rhodopsin. c.Retinal sensitivity decreases. d.Rhodopsin is uncoupled from light transduction.

Which of the following is the best explanation for our perception of color? Select one: a.As many as 100 cones may converge on one ganglion cell. b.The foveae are densely packed with cones. c.Rods contain a single kind of visual pigment. d.Cones come in three types, each sensitive to different wavelengths of light.

The formation of rainbows reflects the fact that: Select one: a. during rain showers, an abundance of electromagnetic energy is available b. light travels in a linear fashion c. visible light consists of multiple wavelengths of light d. X rays become visible by reflecting off of raindrops

Sympathetic innervation is more predominant during __________. Select one: a. close vision b. distant vision c. accommodation of the lenses d. myopic vision

Glaucoma is a disorder in which: Select one: a.the scleral venous sinus becomes blocked. b. all of the above occur c. the retina and optic nerve are compressed d. intraocular pressure increases

Which of the following terms is a synonym for eyelids? Select one: a. Caruncles a.Tarsal plates c. Commissures d. Palpebrae

Pinkeye is an infection of the __________ of the eye. Select one: a. cornea b.lacrimal apparatus c.conjunctiva d. palpebrae

Which of the following is the best explanation for why night vision is fuzzy and indistinct? Select one: a.The foveae are densely packed with cones. b.Rods contain a single kind of visual pigment. c. Cones come in three types, each sensitive to different wavelengths of light. d.As many as 100 cones may converge on one ganglion cell.

Nutrients are delivered and waste products are carried away from the cells of the posterior segment of the eye by blood vessels. However, the cells in the cornea and lens (in the anterior segment) are avascular. Which is the best explanation for how these cells are maintained? Select one: a.The aqueous humor is continuously replenished and flows from the ciliary process to drain in the scleral venous sinus. b.The metabolic activity of these cells is very low. They produce little waste and need few nutrients. c.The nutrients and waste products of the anterior segment diffuse into and through the vitreous humor of the posterior segment. d.These cells, like the cells of the corneal layer of the integument are not living cells.

If you shine a light into one eye both pupils will constrict. The best explanation for this is ________. Select one: a. this in fact does not occur and information from both eyes is always separated b. information from one eye is directly and immediately transferred to the other eye to maintain alignment of the eyes c. sensory input from the retinas of both eyes converges at the optic chiasm and information d.a small portion of light always enters the other eye

The elasticity of the lens decreases with age. This leads to which of the following? Select one: a. a clouding of the lenses know as a cataract Incorrect b. lowered accommodation of the pupillary reflex and blurry vision c. less accommodation of the lenses and difficulty focusing on nearby objects d.less light getting to the retina and diminished visual acuity

Helps maintain the intraocular pressure; located in the anterior part of the eye. Select one: a. Lens b. Retina c. Fovea centralis d. Cornea e.Aqueous humor

Match the following: The sensory layer of the eye. Select one: a. Cornea b.Fovea centralis c.Aqueous humor d. Retina e. Lens