BIOD 152 Anatomy & Physiology II Exam 3 – Latest Updated 2025–
2026 | Special Senses | Fully Solved
1. Which transparent structure forms the anterior one-sixth of the fibrous layer of the eye and
provides major refraction?
A. Cornea
B. Choroid
C. Sclera
D. Retina
Answer: A. Cornea
Rationale: The cornea is transparent and supplies most of the eye's fixed refractive power.
2. The white, tough outer coat of most of the eyeball is the:
A. Cornea
B. Sclera
C. Choroid
D. Iris
Answer: B. Sclera
Rationale: The sclera protects the eye, maintains its shape, and provides attachment for extraocular
muscles.
3. Which vascular, pigmented layer lies between the sclera and retina?
A. Cornea
B. Lens
C. Conjunctiva
D. Choroid
Answer: D. Choroid
Rationale: The choroid provides vascular supply and absorbs stray light.
4. The colored portion of the eye that regulates pupil diameter is the:
A. Cornea
B. Retina
C. Optic disc
D. Iris
Answer: D. Iris
Rationale: Smooth muscle in the iris changes pupil size and therefore controls light entry.
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,5. The pupil is:
A. The optic nerve head
B. An opening in the center of the iris
C. A photoreceptor layer
D. A muscle within the lens
Answer: B. An opening in the center of the iris
Rationale: The pupil is the aperture through which light enters the posterior eye.
6. Which structure changes shape to fine-tune refraction for near and distant objects?
A. Sclera
B. Lens
C. Optic nerve
D. Choroid
Answer: B. Lens
Rationale: The lens alters curvature during accommodation to focus images on the retina.
7. The ciliary muscle contributes to accommodation by changing tension on the:
A. Retinal vessels
B. Optic nerve
C. Suspensory ligaments of the lens
D. Sclera only
Answer: C. Suspensory ligaments of the lens
Rationale: Ciliary muscle contraction changes zonular tension and allows the lens to become more convex
for near vision.
8. For near vision, the lens normally becomes:
A. Flatter
B. Smaller in diameter because the pupil closes
C. Opaque
D. More convex
Answer: D. More convex
Rationale: Accommodation for near objects increases lens curvature and refractive power.
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, 9. Which layer of the eye contains rods and cones?
A. Choroid only
B. Retina
C. Sclera
D. Cornea
Answer: B. Retina
Rationale: The neural retina contains photoreceptor cells called rods and cones.
10. Rods are most important for:
A. Taste discrimination
B. Vision in dim light
C. High-acuity color vision in bright light
D. Detection of sound frequency
Answer: B. Vision in dim light
Rationale: Rods are highly light-sensitive and support scotopic, low-light vision.
11. Cones are most important for:
A. Color vision and high visual acuity
B. Sound transduction
C. Balance
D. Night vision only
Answer: A. Color vision and high visual acuity
Rationale: Cones function best in brighter light and mediate color and fine detail.
12. The area of greatest visual acuity on the retina is the:
A. Ciliary body
B. Fovea centralis
C. Optic disc
D. Ora serrata
Answer: B. Fovea centralis
Rationale: The fovea has densely packed cones and minimal overlying retinal tissue, supporting maximal
acuity.
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2026 | Special Senses | Fully Solved
1. Which transparent structure forms the anterior one-sixth of the fibrous layer of the eye and
provides major refraction?
A. Cornea
B. Choroid
C. Sclera
D. Retina
Answer: A. Cornea
Rationale: The cornea is transparent and supplies most of the eye's fixed refractive power.
2. The white, tough outer coat of most of the eyeball is the:
A. Cornea
B. Sclera
C. Choroid
D. Iris
Answer: B. Sclera
Rationale: The sclera protects the eye, maintains its shape, and provides attachment for extraocular
muscles.
3. Which vascular, pigmented layer lies between the sclera and retina?
A. Cornea
B. Lens
C. Conjunctiva
D. Choroid
Answer: D. Choroid
Rationale: The choroid provides vascular supply and absorbs stray light.
4. The colored portion of the eye that regulates pupil diameter is the:
A. Cornea
B. Retina
C. Optic disc
D. Iris
Answer: D. Iris
Rationale: Smooth muscle in the iris changes pupil size and therefore controls light entry.
Page 1
,5. The pupil is:
A. The optic nerve head
B. An opening in the center of the iris
C. A photoreceptor layer
D. A muscle within the lens
Answer: B. An opening in the center of the iris
Rationale: The pupil is the aperture through which light enters the posterior eye.
6. Which structure changes shape to fine-tune refraction for near and distant objects?
A. Sclera
B. Lens
C. Optic nerve
D. Choroid
Answer: B. Lens
Rationale: The lens alters curvature during accommodation to focus images on the retina.
7. The ciliary muscle contributes to accommodation by changing tension on the:
A. Retinal vessels
B. Optic nerve
C. Suspensory ligaments of the lens
D. Sclera only
Answer: C. Suspensory ligaments of the lens
Rationale: Ciliary muscle contraction changes zonular tension and allows the lens to become more convex
for near vision.
8. For near vision, the lens normally becomes:
A. Flatter
B. Smaller in diameter because the pupil closes
C. Opaque
D. More convex
Answer: D. More convex
Rationale: Accommodation for near objects increases lens curvature and refractive power.
Page 2
, 9. Which layer of the eye contains rods and cones?
A. Choroid only
B. Retina
C. Sclera
D. Cornea
Answer: B. Retina
Rationale: The neural retina contains photoreceptor cells called rods and cones.
10. Rods are most important for:
A. Taste discrimination
B. Vision in dim light
C. High-acuity color vision in bright light
D. Detection of sound frequency
Answer: B. Vision in dim light
Rationale: Rods are highly light-sensitive and support scotopic, low-light vision.
11. Cones are most important for:
A. Color vision and high visual acuity
B. Sound transduction
C. Balance
D. Night vision only
Answer: A. Color vision and high visual acuity
Rationale: Cones function best in brighter light and mediate color and fine detail.
12. The area of greatest visual acuity on the retina is the:
A. Ciliary body
B. Fovea centralis
C. Optic disc
D. Ora serrata
Answer: B. Fovea centralis
Rationale: The fovea has densely packed cones and minimal overlying retinal tissue, supporting maximal
acuity.
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