Question

in the retina, this very small spot has the greatest visual acuity:
○ fovea centralis
○ fundus
○ optic disc
○ pigmented layer
17 multiple choice 1 point
select the statement that is most correct:
○ the dorsal root ganglion is a motor - only structure.
○ afferent nerve fibers are sensory neurons.
○ the cell bodies of afferent ganglia are located in the spinal cord.
18 multiple choice 1 point
which lobe of the cerebrum is vision mapped out?
○ frontal
○ occipital
○ temporal
○ parietal

Explanation:

Question (above question 17):

To determine the spot in the retina with the greatest visual acuity, we analyze each option:

• fovea centralis: It is a small pit in the macula lutea of the retina, containing a high density of cone cells (responsible for sharp, detailed vision), giving it the greatest visual acuity.
• fundus: Refers to the back of the eye (retina, optic disc, macula, etc.), not a specific spot with maximum acuity.
• optic disc: Is the blind spot (where the optic nerve exits, no photoreceptors), so no visual acuity here.
• pigmented layer: The outer layer of the retina (RPE) that supports photoreceptors, not a spot for visual acuity.

So the correct option is the one with fovea centralis.

Analyze each option:

• "The dorsal root ganglion is a motor - only structure": Dorsal root ganglia contain cell bodies of sensory neurons, so this is incorrect.
• "Afferent nerve fibers are sensory neurons": Afferent (sensory) nerve fibers carry sensory information from the periphery to the central nervous system, so they are sensory neurons. This is correct.
• "The cell bodies of afferent ganglia are located in the spinal cord": Cell bodies of afferent (sensory) ganglia (like dorsal root ganglia) are located outside the spinal cord, in the ganglia themselves. So this is incorrect.

The cerebrum's lobes have specific functions:

• frontal lobe: Involved in motor control, decision - making, etc.
• occipital lobe: Is the primary visual cortex, where visual information is processed and mapped.
• temporal lobe: Involved in hearing, memory, etc.
• parietal lobe: Involved in somatosensory (touch, etc.) processing and spatial awareness.

So the lobe where vision is mapped is the occipital lobe.

Answer:

A. fovea centralis

Question 17: