Question 1

Which of the following statements best describes the function of the lens in the human eye?

Accepted Answer

It changes shape to precisely focus light on the retina.

Question 2

A patient presents with difficulty seeing in dim light but has normal color vision in bright light. Which photoreceptor type is most likely dysfunctional?

Accepted Answer

Rods

Question 3

Which process is responsible for the conversion of photon energy into a graded receptor potential in the retina?

Accepted Answer

Phototransduction

Question 4

During light adaptation, which of the following occurs in the retina?

Accepted Answer

Both rods and cones are strongly stimulated, and large amounts of pigments are broken down instantaneously.

Question 5

Which equation best represents the wavelength range of visible light detected by the human eye?

Accepted Answer

$$400 \mathrm{\ nm} \leq \lambda \leq 700 \mathrm{\ nm}$$

Question 6

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

Accepted Answer

It lacks photoreceptors entirely.

Question 7

A person exposed to bright sunlight suddenly enters a dark room and initially cannot see. Which adaptation process is responsible for the gradual improvement in vision?

Accepted Answer

Dark adaptation

Question 8

Which neurotransmitter is released by gustatory epithelial cells during taste transduction, leading to depolarization of the sensory neuron?

Accepted Answer

ATP

Question 9

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

Accepted Answer

Cones require bright light for activation and provide detailed, high-resolution vision.

Question 10

Which of the following disorders is most likely caused by a problem with the equilibrium sensory system?

Accepted Answer

Vertigo

Question 11

Which of the following best describes the role of cGMP in phototransduction?

Accepted Answer

cGMP opens cation channels in the dark, allowing $$\mathrm{Na^+}$$ and $$\mathrm{Ca$$^{2+}$$}$$ influx and depolarization.

Question 12

Which of the following is a correct sequence of signal transmission in the retina?

Accepted Answer

Photoreceptors → Bipolar cells → Ganglion cells

Question 13

Which taste sensation is primarily triggered by the influx of $$\mathrm{Na^+}$$ ions?

Accepted Answer

Salty

Question 14

Which of the following best explains why grass appears green to the human eye?

Accepted Answer

Grass reflects green wavelengths and absorbs all others.

Question 15

Which of the following is a function of the fovea centralis?

Accepted Answer

It contains only cones and is responsible for the highest visual acuity.

Question 16

Which of the following best describes the effect of parasympathetic stimulation on the pupil?

Accepted Answer

It causes the pupil to constrict by contracting circular muscles.

Question 17

Which of the following is TRUE regarding the renewal of photoreceptor outer segments?

Accepted Answer

Outer segments are renewed every 24 hours, with tips fragmenting off and being phagocytized.

Question 18

Which of the following is the correct order of events in phototransduction in rods?

Accepted Answer

Light activates rhodopsin → Transducin activates PDE → cGMP breaks down → Cation channels close → Cell hyperpolarizes

Question 19

Which of the following is a real-world example of a sensory disorder caused by malfunction of the olfactory system?

Accepted Answer

Anosmia

Chapter 15: The Special Senses – Vision, Taste, Smell, Hearing, and Equilibrium

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