Medical Science, Chapter 47: Digestive System

nutrients (p. 1012)

substances in food that are used as energy sources to power the systems of the body

ingestion (p. 1013)

the process of taking food into the digestive cavity

ruminants (p. 1013)

hooved animals with a stomach divided into four chambers

filter feeders (p. 1014)

remove suspended food particles from the water they inhabit

gastrovascular cavity (p. 1015)

central digestive cavity with a single opening

motility (p. 1015)

the mixing and propulsive movements of the digestive tract

peristalsis (p. 1015)

propulsive activity characteristic of most regions of the digestive tract - waves of muscular contraction that push the food in one direction

mucosa (p. 1016)

lines the inner space of the digestive tract, consisting of a layer of epithelial tissue and underlying connective tissue

submucosa (p. 1017)

surrounding the mucosa, a connective tissue layer rich in blood vessels, lymphatic vessels, and nerves

visceral peritoneum (p. 1017)

outer connective tissue coat of the digestive tract

parietal peritoneum (p. 1017)

a sheet of connective tissue that lines the walls of the abdominal and pelvic cavities

peritonitis (p. 1017)

inflammation of the peritoneum

incisors (p. 1017)

used for biting and cutting food

canines (p. 1017)

adapted for piercing prey and tearing food

premolars and molars (p. 1017)

specialized for crushing and grinding

dentin (p. 1017)

resembles bone in composition and hardness

pulp cavity (p. 1017)

lies beneath the dentin, is a soft connective tissue containing blood vessels, lymph vessels, and nerves

salivary glands (p. 1017)

three pairs of these secrete about a liter of saliva into the mouth cavity each day

salivary amylase (p. 1017)

an enzyme in the saliva, which begins the chemical digestion of starch into sugar

rugae (p. 1018)

folds of the stomach wall that give the inner lining a wrinkled appearance; gradually smooths out to expand the capacity of the stomach

gastric glands (p. 1018)

their secretions make up gastric juices

peptic ulcer (p. 1019)

open sores that form as a result of digestion of the stomach lining

duodenum (p. 1020)

most chemical digestion takes place in the first portion of the small intestine

villi (p. 1020)

tiny fingerlike projections that digest and absorb nutrients

bile (p. 1021)

consists of water, bile, salts, bile pigments, cholesterol, and lecithin; mechanically digests fats

pancreas (p. 1021)

elongated gland that secretes both digestive enzymes and hormones that help regulate the level of glucose in the blood

trypsin and chymotrypsin (p. 1021)

pancreatic enzymes that digest polypeptides to dipeptides

pancreatic lipase (p. 1021)

degrades fats

pancreatic amylase (p. 1021)

breaks down almost all types of complex carbohydrates, except cellulose, into disaccharides

ribonuclease and deoxyribonuclease (p. 1021)

split the nucleic acids (DNA and RNA) to free nucleotides

maltase (p. 1021)

splits maltose into two glucose molecules

dipeptidases (p. 1021)

released by the duodenum split small peptides to amino acids

emulsification (p. 1022)

bile salts break down large masses of fat into smaller droplets

gastrin, secretin, CCK, GIP (p. 1022)

hormones that help regulate the digestive system

lacteal (p. 1023)

a network of capillaries and central lymph vessel inside each villus

hepatic portal vein (p. 1023)

amino acids and glucose are transported into the liver by this

cecum (p. 1023)

a blind pouch formed by the small and big intestines joining together

rectum (p. 1023)

last portion of the large intestine

ileocecal valve (p. 1023)

sphincter into the large intestine

anabolism (p. 1024)

includes the synthetic aspects of metabolism, such as the production of proteins and nucleic acids

catabolism (p. 1024)

includes breakdown processes, such as hydrolysis

fiber (p. 1024)

mainly a mixture of cellulose and other indigestible carbohydrates

lipoproteins (p. 1025)

lipids that are bound to proteins an transported as large molecular complexes

fat-soluble vitamins (p. 1026)

A, D, E, and K

water-soluble vitamins (p. 1026)

B and C

minerals (p. 1026)

inorganic nutrients ingested in the form of salts dissolved in food and water

trace elements (p. 1027)

minerals required in amounts less than 100 mg per day

antioxidants (p. 1028)

destroy free radicals and other reactive molecules

phytochemicals (p. 1028)

plant compounds that promote health; many are antioxidants

metabolic rate (p. 1029)

the amount of energy liberated by the body per unit time

gherlin (p. 1029)

hormone secreted by the stomach when it’s empty to stimulate appetite

leptin and insulin (p. 1029)

critical in regulating energy metabolism

body mass index/BMI (p. 1030)

measure of body size and and index of weight in relation to height

set point (p. 1030)

steady state around which body is regulated