MEDICAL BIOLOGY, HUMAN ANATOMY, PHYSIOLOGY AND PATHOLOGY - Y.I. Fedonyuk 2010

ANATOMY, PHYSIOLOGY, PATHOLOGY

SECTION 7. THE NUTRITIONAL PROCESS AND ITS PATHOLOGY

ANATOMY AND PHYSIOLOGY OF THE DIGESTIVE ORGANS

LIPID METABOLISM

Fats (Lipids) include neutral fats, which consist of glycerol and Fatty acids, as well as lipoids (lecithin and Cholesterol). Fats perform structural and energy-yielding Functions in the body. The oxidation of 1 g of fat releases 9.3 kcal of heat, which represents its energy function.

The structural function lies in the fact that fat is a component of Cell membranes and protoplasm. The total amount of fat in the body ranges from 10–30% of body weight. In Disorders of Lipid METABOLISM, The amount of stored fat can reach up to 50% of a person's weight.

In the digestive tract, fats are broken down into glycerol and fatty acids. As they pass through the Cells of the intestinal mucosa, fats specific to the Organism are resynthesized from these components and absorbed into the Lymph, and to a lesser extent, directly into the Blood.

In addition to performing energy and structural functions, fat serves as a solvent for Fat-soluble Vitamins, which cannot be absorbed into the internal environment in any other form.

Fat is synthesized in the body not only from dietary fat, but also from Proteins and, notably, CARBOHYDRATES. Lipid Metabolism is regulated by the nervous and endocrine systems. Fat synthesis in the body is promoted by glucocorticoids of the adrenal cortex, Insulin from the Pancreas, and The activity of the Parasympathetic division of the Autonomic Nervous system. Conversely, the activity of the sympathetic nervous system, adrenaline from The adrenal medulla, thyroxine from The Thyroid Gland, and somatotropic hormone from the Pituitary Gland stimulate fat oxidation.