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