Structure X as a Thermoreceptor in Skin

Steps:

• Examine skin diagram layers: epidermis, dermis contain sensory receptors.
• Identify X's location: embedded in dermis or epidermis for sensory detection.
• Match function to sensory role: detects environmental changes like temperature.
• Eliminate non-sensory options: X aligns with thermoreceptor physiology.

Why B is correct:

• Thermoreceptors are specialized nerve endings in skin that detect temperature changes, signaling the brain to maintain homeostasis per sensory physiology.

Why the others are wrong:

• A: Capillary constriction is regulated by smooth muscle and autonomic nerves, not a specific structure like X.
• C: Impulses from CNS are carried by motor neurons to effectors, not received by sensory structures.
• D: Sweat gland stimulation occurs via cholinergic sympathetic fibers, a neural pathway unrelated to X.

Final answer: B