Question | Answer |
absorption | the transport of the products of digestion from the digestive system into the circulatory system |
active site (of enzyme) | part of an enzyme where substrates bind and undergo a chemical reaction |
alimentary canal | the tube through which food is processed, beginning at the mouth and ending at the anus; also known as the digestive tract |
amino acid | a building block of protein |
amylase | an enzyme in the saliva & pancreatic juice that catalyzes the hydrolysis of starch to into simpler carbohydrates |
appendix | A tube-shaped sac attached to and opening into the lower end of the large intestine in humans and some other mammals. |
bicarbonate ions | liquid substance secreted by pancreas into the beginning of the small intestine in order to neutralize HCl from the stomach |
bile | a greenish-yellow fluid secreted by the liver that helps digest fat |
bulk feeder | a feeding strategy in which animals eat pieces of other organisms or swallow them whole |
canines | one of the four pointed conical teeth (two in each jaw) located between the incisors and the premolars (fangs). |
carbohydrase | an enzyme that acts on carbohydrate molecules. |
carbohydrates | Any of a group of organic compounds that includes sugars, starches, celluloses, and gums and serves as a major energy source in the diet. Generally contain a ratio of 1 carbon:2 hydrogen:1 oxygen in their chemical formula |
carnivore | an animal that eats flesh. |
cellulose | An insoluble polysaccharide that is the main constituent of plant cell walls and of vegetable fibers such as cotton. |
chemical digestion | the chemical breakdown of nutrient molecules into smaller molecules by enzyme action |
cholesterol | A sterol type compound found in most body tissues and important in metabolism. |
chyme | a thick liquid produced in the stomach and made of digested food combined with gastric juice |
chymotrypsin | A pancreatic digestive enzyme that catalyzes the hydrolysis of certain proteins in the small intestine into polypeptides and amino |
cirrhosis | the irreversible replacement of healthy liver tissue with non-functioning scar tissue; most commonly caused by excessive alcohol intake or hepatitis |
colon | main part of the large intestine, which passes from the cecum to the rectum and absorbs water and electrolytes from food |
common bile duct | a duct formed by the hepatic and cystic ducts; opens into the duodenum. Connects the liver and gall bladder to the small intestine |
Crohn’s disease | A chronic inflammatory disease of the intestines, esp. the colon and ileum. |
dehydration synthesis (or condensation reaction) | a chemical reaction that involves the loss of water and the formation of a covalent bond between two molecules in the presence of an enzyme |
diabetes | a condition in which the body is unable to use glucose for energy |
digestion | The process of breaking down food by mechanical and enzymatic action in the stomach and intestines into substances that can be used by the organism for its own processes. |
disaccharide | a sugar made up of two monosaccharide molecules |
disaccharidase (e.g. maltase, sucrase, lactase) | an enzyme that breaks disaccharide molecules into monosaccharide molecules |
duodenum | a short, wide U-shaped section of the small intestine into which food passes from the stomach |
elimination (egestion) | the final act of digestion by which organisms eliminate solid, semisolid or liquid waste material (feces) from the body |
emulsification | a liquid containing very small droplets of fat or oil suspended in a fluid, usually water |
endoscope (two types) | An instrument that can be introduced into the body to give a view of its internal parts (pill or snake-like) |
enzymes | a protein molecule that helps speed up important chemical reactions in the body |
epiglotis | A flap of cartilage at the root of the tongue, which is depressed during swallowing to cover the opening of the windpipe. |
esophageal (cardiac) sphincter | the anatomical term for the part of the stomach attached to the esophagus that controls the release of fluid, made from a ring of muscle. |
esophagus | the muscular tube through which food passes from the mouth to the stomach |
essential nutrients | a nutrient that cannot be made by the body, and must therefore be obtained from food |
fatty acids | the building blocks of the fat in our bodies and in the food we eat, made from a chain of carbons and hydrogens. |
fluid feeder | Animals such as aphids, ticks, and mosquitoes that pierce the body of a host plant or animal and obtain food from sucking liquids |
gall bladder | The small sac-shaped organ beneath the liver, in which bile is stored after secretion by the liver and before release into the intestine. |
gallstones | A small, hard crystalline mass formed abnormally in the gallbladder, often causing severe pain and blockage of the bile duct. |
gastric juice | a mixture of hydrochloric acid, salts, enzymes, water, and mucus that is produced by glands in the stomach to help digest food |
glycerol | backbone molecule that makes up fats. |
glycogen | a polysaccharide made up of glucose units |
hepatitis | inflammation of the liver, most commonly caused by a virus |
herbivore | An animal that feeds on plants. |
hydrolysis | The chemical breakdown of a compound due to reaction with water. |
ileum | the portion of the small intestine that follows immediately after the jejunum |
incisors | A narrow-edged tooth at the front of the mouth, adapted for cutting. |
inflammatory bowel disease (IBD) | A group of chronic intestinal diseases characterized by inflammation of the bowel -- the large or small intestine. |
ingestion | the process of taking food into the body through the mouth (as by eating). |
insulin | A hormone produced in the pancreas by the islets of Langerhans that regulates the amount of glucose in the blood. |
jejunum | the portion of the small intestine that follows immediately after the duodenum |
lacteal | The lymphatic vessels of the small intestine that absorb digested fats. |
large intestine (colon) | The cecum, colon, and rectum collectively. |
larynx | The hollow muscular organ forming an air passage to the lungs and holding the vocal cords in humans and other mammals; the voice box. |
lipase | A pancreatic enzyme that catalyzes the breakdown of fats to fatty acids and glycerol or other alcohols. |
lipid | an organic compound that does not dissolve in water, such as fat and oil |
liver | A large lobed glandular organ in the abdomen of vertebrates, involved in processing digestive products, neutralizing toxins, storing glycogen and other functions. |
macromolecule | a very large molecule made up of smaller molecules that are linked together |
mechanical (physical) digestion | the physical breakdown of large pieces of food into smaller pieces in the mouth by the action of teeth, beak, or other similar structures, and by contractions and churning motions in the stomach |
metabolism | the sum total of all of the chemical reactions that occur in an organism |
microvilli | Each of a large number of minute projections from the surface of some cells. |
minerals | inorganic substances found naturally as chemical compounds or elements |
molars | the rearmost and most complicated kind of tooth in most mammals. In many mammals they grind food |
monosaccharide | a simple sugar with three to seven carbon atoms |
mucus | A substance secreted by mucous membranes and glands for lubrication & protection |
nuclease | An enzyme that cleaves the chains of nucleotides in nucleic acids into smaller units. |
nucleic acids | A complex organic substance present in living cells, esp. DNA or RNA, whose molecules consist of many nucleotides linked in a long chain. |
pancreas | A large gland behind the stomach that secretes digestive enzymes into the duodenum. |
pepsin | an enzyme in gastric juice that helps break down proteins into polypeptides |
peptic ulcer | A lesion in the lining (mucosa) of the digestive tract, typically in the stomach or duodenum, caused by the digestive action of pepsin |
peptide bonds | a bond that holds together the amino acids in a protein |
peristalsis | a wave-like series of muscular contractions in the esophagus |
pharynx | The membrane-lined cavity behind the nose and mouth, connecting them to the esophagus |
polypeptide | a linear chain of several amino acids linked by peptide bonds |
polysaccharides | a large molecule made up of many linked monosaccharide molecules |
protease | An enzyme that breaks down proteins and peptides |
proteins | Any of a class of nitrogenous organic compounds that consist of large molecules composed of one or more long chains of amino acids |
pyloric sphincter | the sphincter muscle of the pylorus that separates the stomach from the duodenum. |
rectum | The final section of the large intestine, terminating at the anus. |
saliva | a watery secretion in the mouth that begins the digestive process |
salivary glands | glands in the mouth that produce saliva to begin the chemical digestion of food |
small intestine | The part of the intestine that runs between the stomach and the large intestine; the duodenum, jejunum, and ileum collectively. |
starch | a carbohydrate macromolecule made up of repeated monosaccharide subunits linked together by dehydration (condensation) synthesis |
substrate (re. enzymes) | The material or substance on which an enzyme acts (reactants). |
substrate feeder | Animals such as earthworms or termites that eat the soil or wood through which they burrow |
trypsin | A digestive enzyme that breaks down proteins in the small intestine. It is secreted by the pancreas in an inactive form, trypsinogen |
ulcer | An open sore on an external or internal surface of the body, caused by a break in the skin or mucous membrane that fails to heal. |
ulcerative colitis | a serious chronic inflammatory disease of the large intestine and rectum characterized by recurrent episodes of abdominal pain and fever |
villi | finger-like projections lining the surface of the small intestine that increase the surface area to improve the absorption of nutrients |
vitamins | organic components in food that are needed in very small amounts for growth and for maintaining good health |