Question

henry touched a hot plate and immediately moved his finger away from it.
which best explains the integumentary systems role in this reaction?
oil in the skin sensed the temperature difference.
nerve endings in the skin responded to the heat.
some hairs stood up when the fingers touched the plate.
his nails absorbed heat and moved his finger away from the plate.

Explanation:

Identify the core physiological event

Henry touched a hot plate and immediately pulled his finger away. This is a classic reflex arc triggered by a painful thermal stimulus. The question asks specifically for the role of the integumentary system (the skin and its accessory structures) in this reaction.

Analyze the functions of skin structures

The skin contains various specialized structures:

• Sebaceous glands (oil glands): Produce sebum to lubricate and waterproof the skin, but do not detect temperature.
• Hair follicles and arrector pili muscles: Responsible for goosebumps (piloerection) during cold exposure, but do not sense or coordinate rapid withdrawal from high heat.
• Nails: Made of hard keratin, providing protection to the fingertips but lacking sensory receptors to detect heat or coordinate movement.
• Sensory nerve endings (thermoreceptors and nociceptors): Located in the dermis and epidermis of the skin, these specialized nerve endings detect temperature changes and painful stimuli, sending signals to the central nervous system to initiate a rapid reflex response.

Evaluate the given options

• Option 1: "Oil in the skin sensed the temperature difference." -> Incorrect. Sebum (oil) has no sensory capabilities.
• Option 2: "Nerve endings in the skin responded to the heat." -> Correct. Sensory receptors (nerve endings) embedded within the integumentary system are responsible for detecting thermal stimuli.
• Option 3: "Some hairs stood up when the fingers touched the plate." -> Incorrect. Piloerection is a response to cold or emotional states, not a mechanism for detecting or reacting to a hot surface.
• Option 4: "His nails absorbed heat and moved his finger away from the plate." -> Incorrect. Nails are non-living keratin structures and cannot actively move the finger.

Answer:

• Oil in the skin sensed the temperature difference.
• Nerve endings in the skin responded to the heat. (Correct answer)
• Some hairs stood up when the fingers touched the plate.
• His nails absorbed heat and moved his finger away from the plate.