Bio Ch 34

  1. absorption
    the process by which nutrients enter the body through the cells lining the digestive tract
  2. amylase
    an enzyme, found in saliva and pancreatic excretions, that catalyzes the breakdown of starch
  3. bile
    a liquid secretion, produced by the liver, that is stored in the gallbladder and released into the small intestine during digestion; consists of a complex mixture of salts, water, and cholesterol
  4. body mass index
    a number derived from an individual's height and weight that is used to estimate body fat
  5. calorie
    the amount of energy required to raise the temperature of one gram of water by one degree Celsius
  6. Calorie
    a unit used to measure the energy content of foods; it is the amount of energy required to raise the temperature of one liter of water one degree Celsius; also called a kilocalorie, equal to 1000 calories
  7. carnivore
    literally "meat eater;" a predatory organism that feeds on herbivores or other carnivores; a secondary (or higher) consumer
  8. chemical digestion
    the process by which particles of food within the digestive tract are exposed to enzymes and other digestive fluids that break down large molecules into smaller subunits
  9. cholecystokinin
    a digestive hormone produced by the small intestine that stimulates the release of pancreatic enzymes
  10. chylomicron
    a particle produced by the cells of the small intestine, consisting of proteins, triglycerides, and cholesterol; transports the products of lipid digestion into the lymphatic system and ultimately the circulatory system
  11. chyme
    an acidic, souplike mixture of partially digested food, water, and digestive secretions that is released from the stomach into the small intestine
  12. digestion
    the process by which food is physically and chemically broken down into molecules that can be absorbed by cells
  13. digestive system
    a group of organs responsible for ingesting food, digesting food into simple molecules that can be absorbed into the circulatory system, and expelling undigested wastes from the body
  14. duodenum
    the first section of the small intestine, in which most food digestion occurs, receives chyme from the stomach, buffers and enzymes from the pancreas, and bile from the liver and gallbladder
  15. elimination
    the expulsion of indigestible materials from the digestive tract, through the anus, and outside the body
  16. epiglottis
    a flap of cartilage in the lower pharynx that covers the opening to the larynx during swallowing; directs food into the esophagus
  17. esophagus
    a muscular, tubular portion of the mammalian digestive tract located between the pharynx and the stomach; no digestion occurs in the esophagus
  18. essential amino acid
    an amino acid that is a required nutrient; the body is unable to manufacture these, so they must be supplied in the diet
  19. essential fatty acid
    a fatty acid that is a required nutruent; the body is unable to manufacture these, so they must be supplied in the diet
  20. essential nutrient
    any nutrient that cannot be synthesized by the body, including certain amino acids and fatty acids, vitamins, minerals, and water
  21. extracellular digestion
    the physical and chemical breakdown of food that occurs outside a cell, normally in a digestive cavity
  22. feces
    semisolid waste material that remains in the intestine after absorption is complete and is voided through the anus; they consist principally of indigestible wastes and other bacteria
  23. food vacuole
    a membranous sac, within a single cell, in which food is enclosed; digestive enzymes are released into this, where intracellular digestion occurs
  24. gall bladder
    a small sac located next to the liver that stores and concentrates the bile secreted by the liver; it is released from the gallbladder to the small intestine through the bile duct
  25. gastric gland
    one of numerous small glands in the stomach lining; contains cells that secrete mucus, hydrochloric acid, or pepsinogen (the inactive form of the protease pepsin)
  26. gastrin
    a hormone produced by the stomach that stimulates acid secretion in response to the presence of food
  27. gastrovascular cavity
    a saclike chamber with digestive functions, found in such invertebrates such as cnidarians (sea jellies, anemones, and related animals); a single opening serves as both the mouth and the anus
  28. herbivore
    literally "plant eater"; an animal that feeds directly and exclusively on producers; a primary consumer
  29. ingestion
    the movement of food into the digestive tract, usually through the mouth
  30. intracellular digestion
    the chemical breakdown of food within single cells
  31. lacteal
    a lymph capillary; found in each villus of the small intestine
  32. lactose intolerance
    the inability to digest lactose (milk sugar) because lactase, the enzyme that digests lactose, is not produced in sufficient amounts; symptoms include bloating, gas pains, and diarrhea
  33. large intestine
    the final section of the digestive tract; consists of the colon and the rectum, where feces are formed and stored
  34. lipase
    an enzyme that catalyzes the breakdown of lipids such as fats
  35. liver
    an organ with varied functions, including bile production, glycogen storage, and the detoxification of poisons
  36. lysosome
    a membrane-bound organelle containing intracellular digestive enzymes
  37. mechanical digestion
    the process by which food in the digestive tract is physically broken down into smaller pieces
  38. metabolic rate
    the speed at which cellular reactions that release energy occur
  39. microvillus
    a microscopic projection of the plasma membrane, which increases the surface area of the cell
  40. mineral
    an inorganic substance, especially one in rocks or soil, or dissolved in water; sodium, calcium, and potassium are essential nutrients that must be obtained in the diet
  41. mouth
    the opening through which food enters a tubular digestive system
  42. nutrient
    a substance acquired from the environment and needed for the survival, growth, and development of an organism
  43. omnivore
    an organism that consumes both plants and animals
  44. pancreas
    a combined exocrine and endocrine gland located in the abdominal cavity next to the stomach; the endocrine portion secretes the hormones insulin and glucagon, which regulates glucose concentration in the blood; the exocrine portion secretes pancreatic juice (a mixture of enzymes, water, and sodium bicarbonate) into the small intestine; the bicarbonate neutralizes acidic chyme entering the intestine from the stomach
  45. pancreatic juice
    a mixture of water, enzymes, and sodium bicarbonate released by the pancreas into the small intestine
  46. peristalsis
    rhythm coordinated contractions of the smooth muscles of the digestive tract that move substances through the digestive tract
  47. pharynx
    in vertebrates, a chamber that is located at the back of the mouth, shared by the digestive and respiratory systems; in some invertebrates, the portion of the digestive tube just posterior to the mouth
  48. protease
    an enzyme that digests proteins
  49. rectum
    the terminal portion of the vertebrate digestive tube where feces are stored until they are eliminated
  50. ruminant
    a herbivorous animal with a digestive tract that includes multiple stomach chambers, one of which contains cellulose-digesting bacteria, and that regurgitates the contents ("cud") of the first chamber for additional chewing
  51. secretin
    a hormone produced by the small intestine that stimulates the production and release of digestive secretions by the pancreas and liver
  52. small intestine
    the portion of the digestive tract, located between the stomach and large intestine, in which most digestion and absorption of nutrients occur
  53. sphincter muscle
    a circular ring of muscle surrounding a tubular structure, such as the esophagus, stomach, or intestine; its contraction and relaxation controls the movement of materials through the tube
  54. stomach
    the muscular sac between the esophagus and small intestine where food is stored and mechanically broken down and in which protein digestion begins
  55. villus
    a finger-like projection of the wall of the small intestine that increases its absorptive surface area
  56. vitamin
    one of a group of diverse chemicals that must be present in trace amounts in the diet to maintain health; used by the body in conjunction with enzymes in a variety of metabolic reactions
Card Set
Bio Ch 34
Bio Ch 34