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Nutrition Chapter 3
Term | Definition |
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Cells | the smallest units in which independent life can exist. All living things are single cells or organisms made of cells |
Enzyme | any of a great number of working proteins that speeds up a specific chemical reaction, such as breaking the bonds of a nutrient, without undergoing change itself. |
Fat cells | cells that specialize in the storage of fat and form the fat tissue. |
Fat cells produce... | enzymes that metabolize fat and hormones involved in appetite and energy balance. |
Tissues | systems of cells working together to perform specialized tasks |
Organs | discrete structural units made of tissues that perform specific jobs. |
Body System | a group of related organs that work together to perform a function. |
Blood | the fluid of the cardiovascular system; composed of water, re and white blood cells, other formed particles, nutrients, oxygen, and other constituents |
Lymph | the fluid that moves from the bloodstream into tissue spaces and then travels in its own vessels, which eventually drain back into the bloodstream |
Arteries | blood vessels that carry blood containing fresh oxygen supplies from the heart to the tissues |
Veins | blood vessels that carry blood, with the carbon dioxide it has collected, from the tissues back to the heart |
Capillaries | minute, weblike blood vessels that connect arteries to veins and permit transfer of materials between blood and tissues |
Plasma | the cell-free fluid part of blood and lymph |
Extracellular Fluid | fluid residing outside the cells that transports materials to and from the cells |
Intracellular Fluid | fluid residing inside the cells that provides the medium for cellular reactions |
Lungs | the body's organs of gas exchange. Blood circulating through the lungs releases its carbon dioxide and picks up fresh oxygen to carry to the tissues |
Intestine | the body's long, tubular organ of digestion and the site of nutrient absorption |
Liver | a large, lobed organ that lies just under the ribs. It filters the blood, removes and processes nutrients, manufactures materials for export other parts of the body, and destroys toxins or stores them to keep them out of the circulation. |
Kidneys | a pair of organs that filter wastes from the blood, make urine, and release it to the bladder for excretion from the body |
Hormones | chemicals that are secreted by glands into the blood in response to conditions in the body that require regulation. These chemicals serve as messengers, acting on other organs to maintain constant conditions. |
Insulin | a hormone from the pancreas that helps glucose enter cells from the blood |
Glucagon | a hormone from the pancreas that stimulates the liver to release glucose into the bloodstream |
Cortex | the outermost layer f something as in the brain where conscious thoughts take place |
Hypothalamus | a part of the brain that senses a variety of conditions in the blood, such as temperature, glucose, salt and others |
Hypothalamus signals... | other parts of the brain or body to adjust those conditions when necessary |
Fight-or-Flight Reaction | the body's instinctive hormone and nerve mediated reaction to danger. Also known as stress response |
Neurotransmitters | chemicals that are released at the end of a nerve cell when a nerve impulse arrives |
Epinephrine | the major hormone that elicits the stress response |
Norepinephrine | a compound related to epinephrine that helps to elicit the stress response |
Metabolism | the sum of all physical and chemical changes taking place in living cells; includes all reactions by which the body obtains and spends the energy from food |
Microbes | bacteria, viruses, or other organisms invisible to the naked eye, some of which cause diseases |
Antigen | a microbe or substance that is foreign to the body |
Immune System | a system of tissues and organs that defend the body against antigens, foreign materials that have penetrated the skin or body linings |
Lymphocytes | white blood cells that participate in the immune response; B-cells and T-cells |
Phagocytes | white blood cells that can ingest and destroy antigens |
T-Cells | lymphocytes that attack antigens |
B-Cells | lymphocytes that produce antibodies |
Antibodies | proteins, made by cells of the immune system, that are expressly designed to combine with and inactivate specific antigens |
Digestive System | the body system composed organs that break down complex food particles into smaller, absorbable products |
Digest | to break molecules into smaller molecules; a main function of the digestive tract with respect to food |
Absorb | to take in, as nutrients are taken into the intestinal cells after digestion; the main function of the digestive tract with respect to nutrients |
Peristalsis | the wavelike muscular squeezing of the esophagus, stomach, and small intestine that pushes their contents along |
Stomach | a muscular, elastic, pouchlike organ of the digestive tract that grinds and churns swallowed food and mixes it with acid and enzymes, forming chyme |
Sphincter | a circular muscle surrounding, and able to close, a body opening |
Chyme | the fluid resulting from the actions of the stomach upon a meal |
Pyloric Valve | the circular muscle of the lower stomach that regulates the flow of partly digested food into the small intestine. Also called pyloric sphincter |
Small Intestine | the 20-foot length of small diameter intestine, below the stomach and above the large intestine, that is the major site of digestion of food and absorption of nutrients |
Large Intestine | the portion of the intestine that completes the absorption process |
Colon | the large intestine |
Feces | waste material remaining after digestion and absorption are comlete; eventually discharged from the body |
Gastric Juice | the digestive secretion of the stomach |
pH | a measure of acidity on a point scale |
Mucus | a slippery coating of the digestive tract lining that protects the cells from exposure to digestive juices |
Bile | a cholesterol-containing digestive fluid made by the liver, stored in the gallbladder, and released into the small intestine when needed. It emulsifies fats and oils to ready them for enzymatic digestion |
Emulsifier | a compound with both water-soluble and fat-soluble portions that can attract fats and oils into water, combining them |
Pancreatic Juice | fluids secreted by the pancreas that contains both enzymes to digest carbohydrate, fat, and protien and sodium bicarbonate, a neutralizing agent |
Bicarbonate | a common alkaline chemical; a secretion of the pancreas; also, the active ingredient of baking soda |
Villi | fingerlike projections of the sheets of cells that line the intestinal tract |
Microvilli | tiny, hairlike projections on each cell of every villus that greatly expand the surface area available to trap nutrient particles and absorb them into the cells |
Hiccups | spasms of both the vocal cords and the diaphragm, causing periodic, audible, short, inhaled coughs |
Heartburn | a burning sensation in the chest area caused by backflow of stomach acid into the esophagus |
Antacids | medications that react t directly and immediately with the acid of the stomach, neutralizing it |
Acid Reducers | prescription and over the counter drugs that reduce the acid output of the stomach, effective for treating severe, persistent forms of heartburn but not for neutralizing acid already present |
Ulcer | an erosion in the topmost, and somtimes underlying, layers of cells that form a lining |
Hernia | a protusion of an organ or part of an organ through the wall of the body chamber that normally contains the organ |
Gastroesophageal Reflux Disease | a severe and chronic splashing of stomach acid and enzymes into the esophagus, throat, mouth, or airway that causes inflammation and injury to those organs |
Constipation | infrequent, difficult bowel movements often caused by diet, inactivity, dehydration, or medication |
Diarrhea | frequent, watery bowel movements usually caused by diet, stress, or irritation of the colon |
Irritable Bowel Syndrome | intermittent disturbance of bowel function, especially diarrhea or alternating diarrhea and constipation; associated with diet, lack of physical activity, or psychological stress |
Nephrons | the working units in the kidneys, consisting of intermeshed blood vessels and tubules |
Bladder | the sac that holds urine until time for elimination |
Glycogen | a storage form of carbohydrate energy (glucose) |
Adipose Tissue | the body's fat tissue, consisting of masses of fat-storing cells and blood vessels to nourish them |