A collection of tan fat-containing tissue is found around the kidneys and adrenal glands of a newborn during surgery. Surgical removal of the tissue would most likely contribute to:

Question

A collection of tan fat-containing tissue is found around the kidneys and adrenal glands of a newborn during surgery.  Surgical removal of the tissue would most likely contribute to:

Quizplus · Accepted Answer

Brown adipose tissue comprises 5% of body mass in neonates. It is also found in hibernating animals, but is present in very small amounts in adult humans. The main function of brown adipose tissue is heat production (Choice E). Neonates have many physiological traits that make them more susceptible to hypothermia, such as an immature nervous system, a high body surface area to volume ratio and a decreased ability to shiver for heat production. Heat production by brown adipose tissue is, therefore, necessary for neonatal survival. White adipose tissue is composed of cells that contain one intracytoplasmic fat droplet. Unlike white adipocytes, brown adipocytes possess several small intracytoplasmic fat vacuoles and considerably more mitochondria. The drastically increased number of mitochondria in these cells gives brown adipose tissue its tan color. Brown adipose tissue has a higher oxygen requirement and contains more capillaries than white adipose tissue. In the majority of human cells, mitochondria are the sites of ATP production. In the mitochondria of brown adipose tissue electron transport and phosphorylation are uncoupled. The protons pumped out by electron transport chain return to the matrix via the mitochondrial membrane protein thermogenin, also known as an uncoupling protein. Thus no ATP is synthesized, and the energy released by electron transport is dissipated as heat. (Choice A) A defect in gluconeogenesis or glycogenolysis would lead to fasting hypoglycemia. These processes primarily occur in the liver. (Choice B) Hypercholesterolemia is most commonly due to a genetic / familial predisposition for high serum cholesterol levels. It may also be induced by diets high in cholesterol. (Choice C) Ketonemia occurs when the liver is depleted of glycogen and utilizes body fat for gluconeogenesis. It occurs during sleep, fasting, starvation, and due to metabolic disturbances in diabetes mellitus. (Choice D) Lactic acidosis results in states of tissue hypoxia or in the presence of defects in oxidative phosphorylation because pyruvate generated by glycolysis is converted to lactate rather than acetyl-CoA in these states. Educational Objective: Brown adipose tissue is found in newborns and in hibernating mammals. Brown adipose cells contain several intracytoplasmic fat droplets and many more mitochondria than white adipose cells. They function to produce heat by uncoupling oxidative phosphorylation with the protein thermogenin.

A Collection of Tan Fat-Containing Tissue Is Found Around the Kidneys