Question

multiple choice 1 point
what category of receptor cell is used to sense changes in the concentration of chemicals in blood?
○ photoreceptor
○ mechanoreceptor
○ thermoreceptor
○ chemoreceptor

5 multiple choice 1 point
vision is processed solely in the thalamus.
○ true
○ false

6 multiple choice 1 point
which of the following nerve fiber tracts are used to conduct nerve impulses between gyri within the same cerebral hemisphere?
○ association tracts
○ commissure tracts
○ projection tracts
○ mammillothalamic tracts

Explanation:

Question 4 (Receptor for chemical concentration in blood)

• Photoreceptors detect light (for vision), so not for chemicals.
• Mechanoreceptors detect mechanical stimuli (like pressure, touch), not chemicals.
• Thermoreceptors detect temperature changes, not chemicals.
• Chemoreceptors are specialized to sense chemical changes (e.g., in blood for oxygen, pH, etc.).

Vision processing starts in the retina, then goes to the thalamus, but the primary visual cortex (in the occipital lobe) is where most visual processing occurs. The thalamus relays visual information but does not process vision "solely"—the cortex is crucial. So the statement is false.

• Association tracts connect gyri within the same cerebral hemisphere.
• Commissure tracts connect hemispheres (e.g., corpus callosum).
• Projection tracts connect the cortex to lower brain/spinal cord.
• Mammillothalamic tracts are part of the limbic system (connect mammillary bodies to thalamus), not for same-hemisphere gyri.

Answer:

D. chemoreceptor

Question 5 (Vision processed solely in thalamus)