Question 1

Which of the following best describes the sequence of events in phototransduction in rods when exposed to light?

Accepted Answer

Light activates rhodopsin, which causes retinal to change shape, activating transducin, which then activates phosphodiesterase (PDE), leading to a decrease in cGMP, closure of Na⁺ channels, hyperpolarization of the photoreceptor, and decreased glutamate release.

Question 2

A patient is diagnosed with myopia. Which lens type would correct their vision, and why?

Accepted Answer

A concave lens, because it diverges light rays so the image focuses on the retina.

Question 3

Which structure in the retina is responsible for the highest visual acuity and why?

Accepted Answer

Fovea centralis, because it contains a high density of cones and no rods.

Question 4

Which of the following best explains why glaucoma can lead to vision loss?

Accepted Answer

Increased intraocular pressure damages the optic nerve, impairing signal transmission to the brain.

Question 5

Which of the following is TRUE regarding the difference between rods and cones?

Accepted Answer

Rods are more sensitive to light and are responsible for night vision, while cones are less sensitive and mediate color vision.

Question 6

A patient presents with hearing loss due to damage to the hair cells in the cochlea. What type of hearing loss is this?

Accepted Answer

Sensorineural hearing loss

Question 7

Which of the following best describes the role of the semicircular canals in the vestibular system?

Accepted Answer

They detect rotational (angular) acceleration of the head.

Question 8

Which ion is primarily responsible for depolarizing hair cells in the cochlea during sound transduction?

Accepted Answer

Potassium (K⁺)

Question 9

A patient with Ménière’s disease experiences dizziness due to excess endolymph. Which structure is most directly affected?

Accepted Answer

Vestibular apparatus (semicircular canals, utricle, saccule)

Question 10

Which of the following best explains why the optic disc is known as the 'blind spot'?

Accepted Answer

It is the region where the optic nerve exits the eye and contains no photoreceptors.

Question 11

Which of the following best describes the mechanism of salty taste transduction?

Accepted Answer

Direct entry of Na⁺ ions through ion channels

Question 12

Which of the following statements about olfactory pathways is correct?

Accepted Answer

Olfactory signals bypass the thalamus and project directly to the olfactory cortex.

Question 13

Which of the following best explains lateral inhibition in the retina?

Accepted Answer

It sharpens visual signals by inhibiting neighboring cells, increasing contrast.

Question 14

Which of the following is the correct order of structures that sound waves pass through from the external environment to the auditory nerve?

Accepted Answer

Auricle → Tympanic membrane → Ossicles → Oval window → Cochlea → Hair cells → Auditory nerve

Question 15

Which of the following best describes the function of otoliths in the vestibular system?

Accepted Answer

They detect linear acceleration and head position by moving in response to gravity.

Question 16

A patient has difficulty distinguishing between sweet and umami tastes but can still taste salty and sour. Which type of receptor is most likely dysfunctional?

Accepted Answer

G-protein coupled receptors (GPCRs)

Question 17

Which of the following best explains why cones provide high visual acuity?

Accepted Answer

Cones are densely packed in the fovea and have a one-to-one connection with bipolar cells.

Question 18

Which of the following is a correct statement about the 'dark current' in photoreceptors?

Accepted Answer

In darkness, Na⁺ channels are open, causing depolarization of the photoreceptor.

Question 19

A patient with cataracts is experiencing vision loss. What is the underlying cause?

Accepted Answer

Clouding of the lens prevents light from properly reaching the retina.

Special Senses: Vision, Hearing, Balance, Taste, and Smell – Study Guide

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