.
BIOL251 Human Anatomy & Physiology I w/Lab 2026
LATEST EDITION WITH CORRECT ANSWERS WELL
VERIFIED WITH RATIONALES.
Module 8: Eye and Vision Exam Review
SECTION A: EXTERNAL EYE STRUCTURES (Questions 1-25)
Question 1
Identify the eye structure denoted by the letter A in the diagram:
A) Palpebral fissure
B) Iris
C) Lacrimal caruncle
D) Sclera
E) Cornea
Correct ANSWER: C) Lacrimal caruncle
Rationale: The lacrimal caruncle is the small, pink, fleshy nodule located at the medial angle (inner
corner) of the eye. It contains modified sebaceous and sweat glands. It is important clinically as it can
become inflamed (carunculitis) and is a landmark for the lacrimal puncta.
Question 2
The palpebral fissure is best described as:
,A) The opening between the eyelids
B) The pink tissue at the medial corner of the eye
C) The transparent anterior portion of the eye
D) The colored portion of the eye
E) The white outer layer of the eye
Correct ANSWER: A) The opening between the eyelids
Rationale: The palpebral fissure is the elliptical opening between the upper and lower eyelids when the
eyes are open. It measures approximately 25-30 mm horizontally and 10-15 mm vertically in adults. The
size of the palpebral fissure can be affected by conditions such as Horner's syndrome (ptosis) or Graves'
disease (widening).
Question 3
Which structure is responsible for the color of the eye?
A) Cornea
B) Sclera
C) Iris
D) Pupil
E) Lens
,Correct ANSWER: C) Iris
Rationale: The iris is the pigmented muscular diaphragm between the cornea and lens. Its color is
determined by melanin concentration: brown eyes have high melanin, blue eyes have low melanin, and
green/hazel eyes have intermediate levels. The iris also contains two smooth muscle groups: the
sphincter pupillae (parasympathetic, constricts pupil) and dilator pupillae (sympathetic, dilates pupil).
Question 4
The lacrimal caruncle contributes to the eye's tear film by:
A) Storing tears
B) Draining tears into the nasal cavity
C) Secreting oily substances that prevent tear evaporation
D) Producing aqueous humor
E) Providing blood supply to the cornea
Correct ANSWER: C) Secreting oily substances that prevent tear evaporation
Rationale: The lacrimal caruncle contains sebaceous and sudoriferous glands that produce an oily
secretion. This contributes to the lipid layer of the tear film, which prevents rapid evaporation of tears
and maintains ocular surface lubrication. It does NOT store tears (the lacrimal sac does this) nor drain
tears (the nasolacrimal duct does this).
Question 5
The tarsal plates (tarsi) are found in which structure?
A) Cornea
, B) Sclera
C) Eyelids
D) Iris
E) Choroid
Correct ANSWER: C) Eyelids
Rationale: Tarsal plates are dense connective tissue structures found within the upper and lower eyelids.
They provide structural support and contain the meibomian glands, which secrete the lipid layer of the
tear film. The upper tarsal plate is larger (approximately 10-12 mm) than the lower (approximately 5
mm).
Question 6
Which of the following is NOT a function of the eyelids?
A) Protection from foreign particles
B) Distribution of tear film
C) Light regulation
D) Sound amplification
E) Lubrication of the cornea
Correct ANSWER: D) Sound amplification
BIOL251 Human Anatomy & Physiology I w/Lab 2026
LATEST EDITION WITH CORRECT ANSWERS WELL
VERIFIED WITH RATIONALES.
Module 8: Eye and Vision Exam Review
SECTION A: EXTERNAL EYE STRUCTURES (Questions 1-25)
Question 1
Identify the eye structure denoted by the letter A in the diagram:
A) Palpebral fissure
B) Iris
C) Lacrimal caruncle
D) Sclera
E) Cornea
Correct ANSWER: C) Lacrimal caruncle
Rationale: The lacrimal caruncle is the small, pink, fleshy nodule located at the medial angle (inner
corner) of the eye. It contains modified sebaceous and sweat glands. It is important clinically as it can
become inflamed (carunculitis) and is a landmark for the lacrimal puncta.
Question 2
The palpebral fissure is best described as:
,A) The opening between the eyelids
B) The pink tissue at the medial corner of the eye
C) The transparent anterior portion of the eye
D) The colored portion of the eye
E) The white outer layer of the eye
Correct ANSWER: A) The opening between the eyelids
Rationale: The palpebral fissure is the elliptical opening between the upper and lower eyelids when the
eyes are open. It measures approximately 25-30 mm horizontally and 10-15 mm vertically in adults. The
size of the palpebral fissure can be affected by conditions such as Horner's syndrome (ptosis) or Graves'
disease (widening).
Question 3
Which structure is responsible for the color of the eye?
A) Cornea
B) Sclera
C) Iris
D) Pupil
E) Lens
,Correct ANSWER: C) Iris
Rationale: The iris is the pigmented muscular diaphragm between the cornea and lens. Its color is
determined by melanin concentration: brown eyes have high melanin, blue eyes have low melanin, and
green/hazel eyes have intermediate levels. The iris also contains two smooth muscle groups: the
sphincter pupillae (parasympathetic, constricts pupil) and dilator pupillae (sympathetic, dilates pupil).
Question 4
The lacrimal caruncle contributes to the eye's tear film by:
A) Storing tears
B) Draining tears into the nasal cavity
C) Secreting oily substances that prevent tear evaporation
D) Producing aqueous humor
E) Providing blood supply to the cornea
Correct ANSWER: C) Secreting oily substances that prevent tear evaporation
Rationale: The lacrimal caruncle contains sebaceous and sudoriferous glands that produce an oily
secretion. This contributes to the lipid layer of the tear film, which prevents rapid evaporation of tears
and maintains ocular surface lubrication. It does NOT store tears (the lacrimal sac does this) nor drain
tears (the nasolacrimal duct does this).
Question 5
The tarsal plates (tarsi) are found in which structure?
A) Cornea
, B) Sclera
C) Eyelids
D) Iris
E) Choroid
Correct ANSWER: C) Eyelids
Rationale: Tarsal plates are dense connective tissue structures found within the upper and lower eyelids.
They provide structural support and contain the meibomian glands, which secrete the lipid layer of the
tear film. The upper tarsal plate is larger (approximately 10-12 mm) than the lower (approximately 5
mm).
Question 6
Which of the following is NOT a function of the eyelids?
A) Protection from foreign particles
B) Distribution of tear film
C) Light regulation
D) Sound amplification
E) Lubrication of the cornea
Correct ANSWER: D) Sound amplification
