A healthy term neonate kept in a cool delivery room maintains its core temperature without shivering. The metabolic process responsible for this heat production is located in which tissue and mediated by which protein?

• A Brown adipose tissue, mediated by uncoupling protein 1 (thermogenin) ✓
• B Skeletal muscle, mediated by ryanodine receptor calcium leak
• C White adipose tissue, mediated by hormone-sensitive lipase
• D Liver, mediated by thyroid hormone induced Na-K ATPase

Explanation

Neonates have negligible shivering capacity and rely on non-shivering thermogenesis in brown fat, abundant in the interscapular region and around great vessels. Uncoupling protein 1 (thermogenin) in brown fat mitochondria dissipates the proton gradient, so fuel oxidation proceeds without ATP synthesis and energy is released as heat under sympathetic norepinephrine drive. White fat lipase generates fatty acids for fuel, not heat directly, and skeletal muscle shivering is minimal at birth.

Reference: Ganong Review of Medical Physiology, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.