,BIOL251/BIOL 251 Human Anatomy & Physiology I w/Lab
Module 8 Exam | Portage Learning | 2026 Edition (PDF)
1. Which part of the eye controls the amount of light entering the eye by adjusting the size of the pupil?
A) Retina
B) Cornea
C) Iris
D) Optic Nerve
Correct Answer: Iris
Rationale: The iris is the colored part of the eye that contains smooth muscle fibers. It adjusts the size of
the pupil to regulate the amount of light that enters the eye, functioning much like the aperture of a
camera.
2. Which of the following photoreceptors is primarily responsible for vision in dim light conditions?
A) Cones
B) Rods
C) Bipolar cells
D) Ganglion cells
Correct Answer: Rods
Rationale: Rods are photoreceptor cells in the retina that are highly sensitive to light, making them
essential for night vision and vision in low-light conditions. They do not detect color, which is the
function of cones.
3. The photoreceptors of the eye are located in which structure?
A) Cornea
B) Lens
C) Retina
,D) Vitreous humor
Correct Answer: Retina
Rationale: The retina is the innermost layer of the eye and contains the photoreceptor cells (rods and
cones). These cells convert light energy into neural signals that are sent to the brain via the optic nerve.
4. Which structure of the eye is responsible for focusing light onto the retina?
A) Cornea
B) Iris
C) Pupil
D) Lens
Correct Answer: Lens
Rationale: The lens is a transparent, biconvex structure that bends (refracts) light rays to focus them
precisely onto the retina. While the cornea also refracts light, the lens provides the fine adjustment
needed for focusing on objects at varying distances.
5. The primary taste sensations include which of the following?
A) 3 types
B) 4 types
C) 5 types
D) 6 types
Correct Answer: 5 types
Rationale: There are five primary taste sensations: sweet, sour, salty, bitter, and umami. These are
detected by taste receptor cells located in taste buds on the tongue and other areas of the oral cavity.
, 6. Balance (equilibrium) is primarily controlled by which system?
A) Cochlea
B) Vestibular system
C) Retina
D) Optic chiasm
Correct Answer: Vestibular system
Rationale: The vestibular system, located in the inner ear, is responsible for maintaining balance and
equilibrium. It detects head position and movement through structures like the semicircular canals and
otolith organs.
7. The special senses include all of the following EXCEPT:
A) Vision
B) Hearing
C) Touch
D) Taste
Correct Answer: Touch
Rationale: The special senses are vision, hearing, equilibrium (balance), taste (gustation), and smell
(olfaction). Touch is considered a general sense because its receptors are distributed throughout the
body, not localized to a specific organ.
8. Which type of receptors are responsible for the senses of taste and smell?
A) Mechanoreceptors
B) Chemoreceptors
C) Photoreceptors
D) Thermoreceptors
Module 8 Exam | Portage Learning | 2026 Edition (PDF)
1. Which part of the eye controls the amount of light entering the eye by adjusting the size of the pupil?
A) Retina
B) Cornea
C) Iris
D) Optic Nerve
Correct Answer: Iris
Rationale: The iris is the colored part of the eye that contains smooth muscle fibers. It adjusts the size of
the pupil to regulate the amount of light that enters the eye, functioning much like the aperture of a
camera.
2. Which of the following photoreceptors is primarily responsible for vision in dim light conditions?
A) Cones
B) Rods
C) Bipolar cells
D) Ganglion cells
Correct Answer: Rods
Rationale: Rods are photoreceptor cells in the retina that are highly sensitive to light, making them
essential for night vision and vision in low-light conditions. They do not detect color, which is the
function of cones.
3. The photoreceptors of the eye are located in which structure?
A) Cornea
B) Lens
C) Retina
,D) Vitreous humor
Correct Answer: Retina
Rationale: The retina is the innermost layer of the eye and contains the photoreceptor cells (rods and
cones). These cells convert light energy into neural signals that are sent to the brain via the optic nerve.
4. Which structure of the eye is responsible for focusing light onto the retina?
A) Cornea
B) Iris
C) Pupil
D) Lens
Correct Answer: Lens
Rationale: The lens is a transparent, biconvex structure that bends (refracts) light rays to focus them
precisely onto the retina. While the cornea also refracts light, the lens provides the fine adjustment
needed for focusing on objects at varying distances.
5. The primary taste sensations include which of the following?
A) 3 types
B) 4 types
C) 5 types
D) 6 types
Correct Answer: 5 types
Rationale: There are five primary taste sensations: sweet, sour, salty, bitter, and umami. These are
detected by taste receptor cells located in taste buds on the tongue and other areas of the oral cavity.
, 6. Balance (equilibrium) is primarily controlled by which system?
A) Cochlea
B) Vestibular system
C) Retina
D) Optic chiasm
Correct Answer: Vestibular system
Rationale: The vestibular system, located in the inner ear, is responsible for maintaining balance and
equilibrium. It detects head position and movement through structures like the semicircular canals and
otolith organs.
7. The special senses include all of the following EXCEPT:
A) Vision
B) Hearing
C) Touch
D) Taste
Correct Answer: Touch
Rationale: The special senses are vision, hearing, equilibrium (balance), taste (gustation), and smell
(olfaction). Touch is considered a general sense because its receptors are distributed throughout the
body, not localized to a specific organ.
8. Which type of receptors are responsible for the senses of taste and smell?
A) Mechanoreceptors
B) Chemoreceptors
C) Photoreceptors
D) Thermoreceptors
