Lecture 1 Gastrointestinal Tract

Macronutrients

Nutrients that provide energy and are essential for human growth and development; includes carbohydrates, proteins, and lipids.

Caloric intake

The total number of calories consumed through eating and drinking.

Integrative Metabolism

The process by which the body converts nutrients into energy and cellular components, while also managing waste products.

Digestion

The process by which food is broken down into smaller components that can be absorbed and utilized by the body.

Absorption

The process by which nutrients from digested food are taken up by the body's cells after digestion.

Salivary amylase

An enzyme in saliva that helps break down starches into simpler sugars.

Peristalsis

Wavelike muscle contractions that move food through the digestive tract.

Chyme

The semi-fluid mass of partly digested food that exits the stomach and enters the small intestine.

Accessory organs

Organs that assist in the digestive process but are not part of the digestive tract itself, such as the liver, pancreas, and gallbladder.

TCA Cycle (Krebs Cycle)

A series of chemical reactions used by all aerobic organisms to generate energy through the oxidation of acetyl-CoA.

Sphincter

A circular muscle that constricts a passage or closes a natural opening in the body.

Hydrochloric acid (HCl)

A strong acid produced in the stomach that aids in digestion and kills pathogens.

Bile

A digestive fluid produced by the liver and stored in the gallbladder, important for the emulsification of lipids.

Fiber

A type of carbohydrate that the body cannot digest; important for digestive health and regularity.

Digestive enzymes

Biological molecules that speed up the breakdown of complex food particles into smaller, absorbable units.

Absorption mechanisms

Processes such as diffusion, facilitated diffusion, active transport, and pinocytosis by which nutrients are absorbed across cell membranes.

Somatostatin

A hormone released by the stomach and pancreas that inhibits gastric secretions and regulates the digestive process.

Gastrin

A hormone released by G-cells in the stomach that stimulates the secretion of gastric acid (HCl).

Acceptable Macronutrient Distribution Range (AMDR)

A range of intake for each macronutrient that is associated with reduced risk of chronic diseases while providing adequate intakes of essential nutrients.

Nutrient-disease relationships

The connections between nutrient intake and the occurrence or prevention of diseases.

Enzymatic hydrolysis

The process of breaking down compounds by the enzymatic addition of water.