Where is brown adipose tissue distributed in newborns to aid thermogenesis?

• A. Around the scapulae, neck, axillae, and behind the sternum.
• B. In the liver and spleen exclusively.
• C. Only in the lower back region.
• D. In the brain.

Answer: (A)

Brown adipose tissue in newborns is arranged in depots around the upper body to generate heat quickly through non-shivering thermogenesis. Locations such as the neck, interscapular/scapular area, axillae, and behind the sternum place BAT near major blood vessels, allowing rapid heat delivery to the circulating blood when cold exposure triggers sympathetic activation. The heat comes from the mitochondria in brown fat using thermogenin (UCP1) to uncouple respiration and produce warmth rather than ATP. This distribution is why the answer points to areas around the scapulae, neck, axillae, and behind the sternum, and not to the liver, spleen, lower back, or brain.