Question 1

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?
A) The nutrients and waste products of the anterior segment diffuse into and through the vitreous humor of the posterior segment.
B) The metabolic activity of these cells is very low. They produce little waste and need few nutrients.
C) These cells, like the cells of the corneal layer of the integument are not living cells.
D) The aqueous humor is continuously replenished and flows from the ciliary process to drain in the scleral venous sinus.

Accepted Answer

The maintenance of cells in the avascular cornea and lens of the anterior segment is achieved by the continuous replenishment and flow of aqueous humor from the ciliary process to drain in the scleral venous sinus. This flow provides nutrients and removes waste products from these cells.

Question 2

In a person who is color blind,which of the following would you most expect to see?
A) a loss of functions in the rods of their retina
B) an inability to regenerate 11-cis-retinal after bleaching
C) absence of green or red cones in their foveae
D) a loss of their peripheral vision

Accepted Answer

In color blindness, there is a deficiency or absence of either green or red cones in the fovea of the retina, leading to an inability to distinguish between certain colors. This is the most common cause of color blindness. Loss of function in rods (A) would affect night vision, while inability to regenerate 11-cis-retinal (B) is not directly related to color vision. Loss of peripheral vision (D) may not be a sign of color blindness specifically.

Question 3

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?
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 many more cone photoreceptors in the eye than rod photoreceptors.
C) There are several types of cone photoreceptors, each of which enrich the clarity and resolution of vision.
D) A larger proportion of the brain's visual cortex is active during the day when our cone photo receptors are most active.

Accepted Answer

A single cone photoreceptor often connects to a single bipolar cell and a single ganglion cell, allowing for high-resolution color vision. In contrast, the convergence of many rods onto a single ganglion cell in night vision leads to lower resolution.

Question 4

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

Accepted Answer

The overlap in the visual fields of our eyes allows us to subconsciously estimate the distance of objects based on the different angles the image strikes our two retinas. This is known as binocular vision and is important for depth perception.

Question 5

Flavor preferences,our likes and dislikes are said to have a "homeostatic value".Which of the following is the best example of this homeostatic value for taste preferences?
A) The temperature, smell and texture of foods will influence its overall taste.
B) Alkaloids are chemical compounds in plants that are frequently toxic "antifeedant" chemicals. Alkaloids are often unpleasantly bitter.
C) Capsaicin is a chemical compound in chili peppers. Nociceptors in the mouth respond to this chemical with the sensation of heat.
D) Monosodium glutamate is a food additive that stimulates umami taste (gustatory) cells.

Accepted Answer

The homeostatic value of taste preferences refers to the body's ability to use taste preferences and aversions to maintain a balanced diet and avoid harmful substances. Alkaloids are often bitter and unpleasant, which can act as a natural deterrent to consuming harmful plants. Therefore, our dislike of bitter tastes can help protect us from ingesting toxic substances.

Question 6

The elasticity of the lens decreases with age.This leads to which of the following?
A) less light getting to the retina and diminished visual acuity
B) lowered accommodation of the pupillary reflex and blurry vision
C) a clouding of the lenses know as a cataract
D) less accommodation of the lenses and difficulty focusing on nearby objects

Accepted Answer

The elasticity of the lens decreases with age, which leads to less accommodation of the lenses and difficulty focusing on nearby objects. This can result in presbyopia, which is common in individuals over 40 years old.

Question 7

Hair cells in the spiral organ of the ear are never replaced.

Accepted Answer

Hair cells in the spiral organ of the ear can be damaged and lost due to exposure to loud noise, ototoxic drugs or aging. In some cases, some hair cells can regenerate and replace the lost ones, although not at a significant rate. Research is ongoing to find ways to enhance hair cell regeneration and restore hearing loss.

Question 8

Photoreceptors are modified neurons.However,they differ from most neurons in the fact that ________.
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

Accepted Answer

Photoreceptors differ from most neurons in that they will hyperpolarize when stimulated by light, rather than depolarize. This hyperpolarization is caused by the closure of ion channels in response to light, whereas depolarization in typical neurons is caused by the opening of ion channels in response to a neurotransmitter or other stimulus. Photoreceptors are also specialized to detect and respond to energy changes in the external environment, specifically in the form of light. While all neurons are sensitive to changes in their environment, photoreceptors are more specialized for this function.

Question 9

A patient has a loss of hearing in only one ear.Which of the following is likely to be a result?
A) The patient will not be able to localize the origin of sounds.
B) The patient will have increased sensitivity to sound in the unaffected ear.
C) The patient will have a loss of balance with dizziness and vertigo.
D) The patient will not be able to track objects with the eye on the same side as the hearing loss.

Accepted Answer

When a patient has a loss of hearing in only one ear, they will be unable to use binaural cues to localize the origin of sounds. Without this ability, it can be difficult for the patient to determine where sounds are coming from.

Question 10

Select the statement below that is not true with regards to the process of light adaptation.
A) Visual acuity is diminished.
B) Retinal sensitivity decreases.
C) Rhodopsin is uncoupled from light transduction.
D) The activity of rods is reduced by rapid bleaching of rhodopsin.

Accepted Answer

Visual acuity actually improves during light adaptation as the eye adjusts to higher light levels, allowing for better resolution and detail perception.

Question 11

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?
A) Color perception is achieved by activation of various combinations between the three cone types.
B) Color perception is dependent on the millions of rods as well as cone photoreceptors.
C) Shades of color are purely psychological and learned by association with age, infants only seeing in black and white.
D) Colors are added and enhanced in the primary visual cortex of the brain.

Accepted Answer

Color perception is achieved by activation of various combinations between the three cone types. By mixing signals from the three types of cones, our brains are able to perceive a wide range of colors. This is known as trichromatic color vision.

Question 12

Labyrinthitis is a medical condition often caused by viral infection,resulting in swelling and inflammation of the membranous labyrinth.Which of the following symptoms would you most associate with the condition of labyrinthitis?
A) auditory hallucination
B) loss of hearing
C) ringing in the ears (tinnitus)
D) loss of balance and dizziness

Accepted Answer

Loss of balance and dizziness are the most common symptoms of labyrinthitis, as the swelling and inflammation affect the portion of the inner ear responsible for balance and spatial orientation. Auditory hallucinations, loss of hearing, and tinnitus may occur in some cases, but they are not as typical or specific to the condition.

Question 13

Humans can smell as many as 10,000 different odors but have significantly fewer types of olfactory receptors.Which of the following is the best explanation for why humans can distinguish so many smells?
A) The belief that we can smell so many different distinct odors is a psychological process referred to as an uncinate fit or olfactory hallucination.
B) The olfactory pathway travels to location in the brain in which memories are formed and we simply mix this new sensory information with old memories.
C) The sensation of a single, distinct smell is a combination of a variety of chemicals that stimulate different combinations of olfactory receptor cells all at once.
D) Taste receptors that are active at the same time influence the subtlety of what we smell.

Accepted Answer

The sensation of a single, distinct smell is a combination of a variety of chemicals that stimulate different combinations of olfactory receptor cells all at once.

Question 14

Odorants must be volatile to be smelled.

Accepted Answer

Odorants must be volatile (able to evaporate at normal temperatures) in order to be carried by air to the olfactory receptors in the nose and be detected as a smell. Non-volatile compounds cannot be smelled.

Question 15

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

Accepted Answer

The answer of Which of the following is the best...

Question 16

The quality of a sound is based on the atmospheric pressure at the time the sound is generated.

Accepted Answer

The quality of a sound is based on the frequency, amplitude, and harmonic content of the sound wave, and is not affected by atmospheric pressure. However, atmospheric pressure can affect the intensity or loudness of a sound.

Question 17

The sensation of loudness or the volume of a sound is detected by ________.
A) high volume sounds can travel all the way the apex of the scala vestibule with enough energy remaining to deflect hair cells
B) faster vibration of the basilar membrane resulting in a higher frequency of hair cell stimulation
C) greater movement of the basilar membrane resulting in greater deflection of the hair cells
D) vibration along a greater length of the basilar membrane, stimulating a greater number of hair cells

Accepted Answer

Greater movement of the basilar membrane results in greater deflection of the hair cells, which in turn leads to a stronger signal being sent to the brain, indicating a louder sound. Option A is incorrect because the apex of the scala vestibule is responsible for detecting low frequency sounds, while high frequency sounds are detected near the base of the cochlea. Option B is incorrect because faster vibration of the basilar membrane results in a higher pitch or frequency of sound, not necessarily louder volume. Option D is also incorrect because the number of hair cells stimulated does not necessarily correlate with loudness, as the movement and deflection of those hair cells is the determining factor.

Question 18

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

Accepted Answer

Cones come in three types, each sensitive to different wavelengths of light. This allows us to perceive different colors based on the combination and intensity of signals from different types of cones in our eyes.

Question 19

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

Accepted Answer

At night, vision relies more on rods, which are more sensitive to light than cones but do not provide color information because they contain only one type of visual pigment. This makes it difficult to discriminate the color of objects in low light conditions.

Question 20

If you shine a light into one eye both pupils will constrict.The best explanation for this is ________.
A) sensory input from the retinas of both eyes converges at the optic chiasm and information from each eye is delivered to both the left and right sides of the brain
B) information from one eye is directly and immediately transferred to the other eye to maintain alignment of the eyes
C) a small portion of light always enters the other eye
D) this in fact does not occur and information from both eyes is always separated

Accepted Answer

Sensory input from the retinas of both eyes converges at the optic chiasm and information from each eye is delivered to both the left and right sides of the brain. This allows for both pupils to constrict when a light is shone into one eye.

Quiz 15: The Special Senses

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?

In a person who is color blind,which of the following would you most expect to see?

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?

Overlap in the visual fields of our eyes ________.

Flavor preferences,our likes and dislikes are said to have a "homeostatic value".Which of the following is the best example of this homeostatic value for taste preferences?

The elasticity of the lens decreases with age.This leads to which of the following?

Hair cells in the spiral organ of the ear are never replaced.

Photoreceptors are modified neurons.However,they differ from most neurons in the fact that ________.

A patient has a loss of hearing in only one ear.Which of the following is likely to be a result?

Select the statement below that is not true with regards to the process of light adaptation.

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?

Labyrinthitis is a medical condition often caused by viral infection,resulting in swelling and inflammation of the membranous labyrinth.Which of the following symptoms would you most associate with the condition of labyrinthitis?

Humans can smell as many as 10,000 different odors but have significantly fewer types of olfactory receptors.Which of the following is the best explanation for why humans can distinguish so many smells?

Odorants must be volatile to be smelled.

Which of the following is the best explanation for why night vision is fuzzy and indistinct?

The quality of a sound is based on the atmospheric pressure at the time the sound is generated.

The sensation of loudness or the volume of a sound is detected by ________.

Which of the following is the best explanation for our perception of color?

Which of the following is the best explanation of why it is difficult to discriminate the color of an object at night?

If you shine a light into one eye both pupils will constrict.The best explanation for this is ________.