03. Skin sensation circulation and heat exchange – Practice Quiz

Skin Sensation, Circulation, and Heat Exchange: Neurovascular Effectors and Thermal Biophysics

The skin functions as both a sensory receiver and the primary effector organ for whole-body heat dissipation. This questionset explores cutaneous receptor neurophysiology, specialized microvascular networks, autonomic vasomotor pathways, and the biophysics of heat exchange.

Key Learning Areas

• Cutaneous sensory receptors: fast-adapting (Meissner, Pacinian) vs. slow-adapting (Merkel, Ruffini), TRP thermoreceptors (TRPV1, TRPM8), and nociceptive free nerve endings.
• Dermal vascular architecture: subpapillary and deep cutaneous plexuses, capillary loops in dermal papillae, and microvascular capacity.
• Cutaneous vasomotor regulation: sympathetic noradrenergic vasoconstriction (alpha-1/alpha-2), active sympathetic cholinergic vasodilation (VIP, nitric oxide), and the axon reflex (Lewis triple response).
• Arteriovenous anastomoses (glomus bodies): specialized apical shunts (fingertips, toes, ears), sympathetic tone control, and rapid non-nutritive heat dumping.
• Thermal physics at the skin: radiation, conduction, convection, and evaporation, including the latent heat of vaporization ($$2.4\text{ kJ/g}$$).
• Environmental constraints: evaporation limits at high ambient relative humidity, and cutaneous blood flow versus blood pressure defense during dehydration.

Cover image credit: Photo by Ketut Subiyanto on Pexels.