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chemical messengers that are produced in one location, released into the blood, and elicit responses at other locations in the body.
body waste, including unabsorbed food residue, bacteria, mucus, and dead cells which is excreted from the gastrointestinal tract by passing through the anus.
a hollow tube consisting of the mouth, pharynx, esophagus, stomach, small intestine, large intestine, and anus in which digestion and absorption of nutrients occurs
the time between ingestion of food and the elimination of the solid waste from that food
a viscous material produced by glands in the GI tract and other parts of the body. It acts to lubricate, moisten, and protect cells from harsh environments
a protein molecule that accelerates the rate of a chemical reaction without itself being changed
a watery fluid produced and secreted into the mouth by the salivary glands. It contains lubricants, enzymes, and other substances.
an enzyme in saliva, tears, and sweat that is capable of destroying certain types of bacteria
a funnel-shaped opening that connects the nasal passages and mouth to the respiratory passages and esophagus. It is a common passageway for food and air and is responsible for swallowing.
a piece of elastic connective tissue at the back of the throat that covers the opening of the passageway to the lungs during swallowing.
an inactive protein digesting enzyme produced by gastric glands and activated to pepsin by acid in the stomach
a protein digesting enzyme produced by the gastric glands. It is secreted in the gastric juice in an inactive form and activated by acid in the stomach
finger-like protrusions of the lining of the small intestine that participate in the digestion and absorption of nutrients
microvilli or brush border
minute brush-like projections on the mucosal cell membrane that increase the absorptive surface area in the small intestine
a small lymph vessel in the intestine that absorbs and transports the products of fat digestion.
rhythmic local constrictions of the intestine that mix food with digestive juices and speed absorption by repeatedly moving the food mass over the intestinal wall
starch digesting enzyme produced in the pancreas and released into the small intestine
a substance made in the liver and stored in the gallbladder. It is released into the small intestine to aid in fat digestion and absorption
the movement of substances from an area of higher concentration to an area of lower concentration. No energy is required.
the passive movement of water across a semipermeable membrane in a direction that will equalize the concentration of dissolved substances on both sides.
the movement of substances across a cell membrane from an area of lower concentration to an area of lower concentration with the aid of a carrier molecule. No energy is required.
a foreign substance (always a protein) that, when introduced into the body, stimulates an immune response
a protein produced by cells of the immune system that destroys or inactivates foreign substances in the body
gastroesophageal reflux disease (GERD)
a chronic condition in which acidic stomach contents leak back up into esophagus, causing pain and damaging the esophagus
enteral or tube-feeding
a method of feeding by providing a liquid diet directly to the stomach or intestine through a tube placed down the throat or through the wall of the GI tract
total parenteral nutrition (TPN)
a technique for nourishing an individual by providing all needed nutrients directly into the circulatory system.
an inflammation of the stomach lining that causes a reduction in the stomach acid and allows bacterial overgrowth
hepatic portal circulation
the system of blood vessels that collects nutrient-laden blood from the digestive organs and delivers it to the liver.
the system of vessels, organs, and tissues that drains excess fluid from the spaces between cells, transports fat-soluble substances from the digestive tract, and contributes to immune
a small, thin-walled blood vessel where the exchange of gases and nutrients between blood and body cells occurs.
describes a membrane or barrier that will allow some substances to pass freely but will restrict the passage of others
cellular organelle that is responsible for providing energy in the form of adenosine triphoshpate (ATP) for cellular activities.
a series of chemical rections inside a living organism that results in the transformation of one molecule into another
a small organic molecule (not a protein but sometimes a vitamin) that is necessary for the proper functioning of many enzymes
the biochemical reactions by which substances are broken down into simpler molecules releasing energy
ATP (adenosine triphosphate)
the high-energy molecule used by the body to perform energy requiring activities
energy-requiring biochemical reactions in which simpler molecules are combined to form more complex substances
the reactions that break down glucose, fatty acids, and amino acids in the presence of oxygen to produce carbon dioxide, water, and energy in the form of ATP
a metabolic intermediate formed during the breakdown of glucose, fatty acids, and amino acids. It is a two-carbon compound attached to a molecule of CoA
citric acid cycle
also known as the Krebs cycle or the tricarboxylic acid cycle, this the stage of cellular respiration in which two carbons from acetyl-CoA are oxidize, producing two molecules of carbon dioxide
electron transport chain
the final stage of cellular respiration in which electrons are passsed down a chain of molecules to oxygen to form water and produce ATP
refers to a compound that has lost an electron or undergone a chemical reaction with oxygen
the functional unit of the kidney that performs the job of filtering the blood and maintaining fluid balance
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