Nutrition Chapter 5

mucosal folds

The large, visible folds of the mucous lining of the small intestine that increase the absorbing surface area

digestion

The process by which food is broken down in the gastrointestinal tract to release nutrients in forms that the body can absorb

absorption

The process by which nutrients are taken into the cells that line the gastrointestinal tract

chyme

The semi-fluid food mass in the gastrointestinal tract that is present after gastric digestion

metabolism

The sum of the chemical changes in the cell that ultimately produce the materials that are essential for energy, tissue building, and metabolic controls

Peristalsis

The waves of muscle contraction that push food mass through the entire length of the intestines

The main task of the large intestine

absorption of water

bile

an emulsifying agent in fat digestion and absorption. Produced by the liver and stored in the gallbladder

glycogenesis

the anabolic process of creating stored glycogen from glucose

lipogenesis

the anabolic process of forming fat

gluconeogenesis

the formation of glucose from non-carbohydrate substances such as amino acids

pepsin

the main gastric enzyme specific to proteins; it begins breaking large protein molecules into shorter-chain polypeptides; needs gastric hydrochloric acid for activation

catabolism

the metabolic process of breaking down large substances to yield smaller building blocks

anabolism

the metabolic process of building large substances from smaller parts

adipose tissue

the storage site for excess fat

gastrin

A hormone that stimulates the secretion of gastric acid by the parietal cells of the stomach, and that stimulates the chief cells to secrete pepsinogen

pancreatic lipase

A major fat-splitting enzyme produced by the pancreas and secreted into the small intestine to digest fats

pancreatic amylase

A major starch-splitting enzyme secreted by the pancreas that acts in the small intestine

carboxpeptidase

A protein enzyme that breaks off the carboxyl group at the end of peptide chains

trypsin

A protein-splitting enzyme produced in the pancreas and released into the small intestine

salivary amylase

A starch-splitting enzyme in the mouth that is secreted by the salivary glands, also called "ptyalin" from the Greek meaning "spittle"

microvilli

Extremely small, hairlike projections that cover all of the villi on the surface of the small intestine that greatly extend the total absorption surface area. Visible through an electron microscope

chymotrypsin

One of the protein-splitting and milk-curdling pancreatic enzymes activated in the small intestine; it breaks specific amino acid peptide links of protein

mucus

Secreted by the intestinal glands protect the gastrointestinal lining from irritation and erosion caused by the highly acidic contents that enter the duodenum