Chapter 3

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  1. Essential nutrients are nutrients that can be made by the body.
    False, they must be obtained by food.

    The body's cells need nutrients 24 hours a day.

    Each part of the digestive tract has specific functions.

    Digestion begins in the mouth.

    It takes approx two days for a meal to empty from the stomach.
    False, it takes approx 4 hours for a meal to empty from the stomach.

    Nutrients are absorbed in the small intestine.

    The small intestine is longeer than the large intestine.

    The small intestine is lined with fingerlike projections called villi that increase the absorptive area so that if the lining of the small intestine could be spread out flat it would cover an area the size of a tennis court.

    The liver determines the metabolic fate of every nutrient absorbed.

    The pancreas plays no role in the digestive process.
    False, the pancreas produces digestive enzymes and bicarb and secretes them into the small intesine.
  2. The SMALLEST units in which independent life an exist. All living things are single cells or organisms made of cells.
  3. Compounds that MUST be obtained from food because they cannot be synthesized by the body in amounts sufficient to meet physiological needs.
    Essential nutrients
  4. The body's cells most basic needs are:
    • energy (fuel)
    • oxygen
    • water
  5. Encloses each cell's content
  6. Encloses the cell's nucleus
    Inner membrane
  7. Inside the nucleus is:
    DNA, genes
  8. Mitochondrion
    • Where energy is being used*
    • Takes in nutrients and releases energy from them.
  9. Fingerlike projectsion
    Absorb nutrients in intestines
  10. Part of the brain that senses a variety of conditions in the blood such as temp, salt content, glucose content and isgnals other parts ot he brain or body to change those conditions when necessary.
  11. Cells are organized into __
    tissues that are designed to perform specialized tasks.
  12. Tissues can be organized to form __
  13. When several organs work together these organs are considered parts of a __
    body system
  14. Whatever foods we choose must provide energy water and essential nutrients.
  15. Hunger and appetite are experienced in the __ part of the brain.
  16. The GI tract provides the body with a constant supply of water and nutrients, accomplishing this seemingly simple task entails:
    • Passage of food through the GI tract
    • Secretion of digestive juices and enzymes
    • Digestion of the food
    • Absorption of water and nutrients
    • Circulation of blood through the body to distribute absorbed substances
    • Control of these functions.
  17. Out layer of GI tract wall is called
  18. Out layer of GI tract wall protects bl vessels, nerves and lymphatic vessels.
    Also attaches the lower parts of the small intestine (jejunum and ileum) and part of the large intestine (transverse colon) to the abd wall to prevent the intestines from twisting.
  19. Muscularis externa:
    Movement of food through the GI tract is enabled by the different layers of smooth muscle.
  20. As food works its way along the GI tract it is mixed with digestive juices and enzymes in preparation for the digestive process.
  21. Mucousa:
    Innermost layer of GI tract wall, made up of cells that serve vital functions in the digestive process. Some cells secrete gastric juices, digestive enzymes and mucus to protect the lining of the GI tract.
  22. Thick, slippery coating of the intestinal lining (and other body linings) that protects the cells from exposure to digestive juices. THe adjective form is mucous and the coating is often called the mucous membrane.
  23. Digestive process begins in __
    the mouth.
  24. Changes that occur during the oropharyngeal stage of swallowing to prevent the bolus of food from entering the wrong passageway.
  25. Teeth cut off a bite sized portion and then aided by the tongue grind it finely enough to be mixed with saliva and swallowed.
  26. Chewing exposes the surface area of food to digestive secretions.
    Digestive enzymes act only on the surface of food particles.
  27. The mouth contains three salivary glands that secrete salivary amylase (ptyalin) which moistens food during chewing and makes it easier to swallow, amylase also begins the breakdown of complex carbs and is then stopped when the carbs units reach the stomach.
  28. Mixture of food particles and saliva is called
  29. The food bolus must move from the mouth to the esophagus.
    This occurs through the process of swallowing.
  30. Swallowing:
    • Swallowing center inhibits resp center in brain stem
    • Elevation of uvula prevents food from entering nasal passages
    • Position of tongue prevents food from re-entering mouth
    • Epiglottis is pressed down over closed glottis as auxillary mechanism to prevent food from entering airways.
    • Tight apposition of vocal folds across glottis prevents food from entering resp airways
  31. The first part of swallowing process is voluntary bc we choose to chew and then with the help of the tongue, move the bolus toward the pharynx.
    From there on the process is pretty much automatic (involuntary)
  32. Does digestion take place in the esophagus?
  33. Purpose of esophagus:
    To serve as a vehicle for the food bolus as the bolus travels from the mouth to the stomach.
  34. During the swallowing process a phincter (circular bandof muscle fibers that constricts a passage or closes a natural opening in the body) at the top of the esophagus relaxes to permit the bolus to enter.
    Muscle layers push the bolus down the length of the esophagus to the stomach.
  35. The wavelike squeezing motions of the stomach and intestines that push their contents along the digestive tract.
  36. Lower esophageal sphincter (LES) or gastroesophageal sphincter is normally constricted or closed, and plays an important role in protecting the esophagus from stomach acid that might otherwise splash back into the esophagus.
  37. The stomach carries out three jobs during digestion:
    • Stores a size-able amount o food until the food can be processed
    • Forms a mixture of food and gastric secretions which become a semi liquid called chyme
    • Controls movement of the chyme into the small intestine at a rate suitable for proper digestion and absorption by the small intestine
  38. Long tubular organ of digestion that is the site o nutrient absorption
    Small intestine
  39. Empty stomach has a volume of about 1 1/2 ounces or 3 tblspoon
    Can increase to 1 liter
  40. Food entering the stomach from the esophagus triggers peristalsis in the stomach which causes the stomach to "churn" thereby mixing the food with hydrochloric acid and other gastric secretions to form chyme
  41. Circular muscle surrounding the lower end of the stomach and is normally almost completely closed, controls the exodus of stomach contents allowing only a little at a time to be squirted forcefully into the small intestine
    Pyloric sphincter
  42. Produced by specialized cells in the stomach, necessary for absorption of vitamin b12 in small intestine.
    Intrinsic factor
  43. Liquids pass through the stomach quickly while solids stay in the stomach until they are mixed thoroughly with stomach secretions
    Carbs tend to move through the stomach more quickly than proteins and fatty foods may stay in the stomach for as long as six hours
  44. The rate of stomach emptying (also controlled by the central nervous system and hormonal mechanisms) plays an important role in digestion and absorption of nutrients from foods
  45. The small intestine is the organ of __ and __
    digestion and absorption
  46. Called small because it is small in diameter
  47. Compound made from cholesterol by the LIVER, stored in the GALLBLADDER and secreted into the small intestine, it emulsifies lipids to ready them for enzymatic digestion
  48. Chemical that NEUTRALIZES acid; a secretion of the PANCREAS
  49. A protein catalyst (a compound that facilitates - speeds up the rate of a chemical reaction without itself being altered in the process
  50. Stomach secrets:
    • Gastric juice
    • Hydrochloric acid
    • Gastric protease
    • Intrinsic factor
    • Mucus
  51. Liver and gallbladder secretes:
  52. Pancreas secretes:
    • Bicarbonate
    • Enzymes (break down carbs, fats, and proteins)
  53. Finger-like projections of the sheet of cells that line the GI tract; it will make the surface area much greater than it would otherwise be
  54. Tiny hairlike projections on each cell of the intestinal tract lining that can trap nutrient particles and trans-locate them into the cells
  55. No digestive enzymes are secreted in large intestine
  56. Primary function of large intestine:
    • Absorb dissolved minerals and water
    • Eliminate waste products
  57. Cells lining the colon are specialized for absorbing these minerals and retrieving water for recycling
  58. Accessory organs:
    • Liver
    • Gallbladder
    • Pancreas
  59. Large lobed organ that lies under the ribs and filters the blood in the process removing processing and readying for redistribution many of its materials
  60. Determines the metabolic fate of every nutrient we digest and absorb
  61. Liver produces 1 liter of bile daily
  62. Bile is made up o water, bile salts bile pigments and cholesterol, slightly alkaline which helps neutralize acidic chyme in the intestinal tract
  63. Sac that is attached to the liver where bile is stored and concentrated
  64. A gland having both endocrine and exocrine functions
  65. Helps regular blood glucose levels through secretion of insulin and glucagon into the blood
    Pancreas (endocrine function)
  66. Main function of the pancreas are exocrine.
    Bicarb and digestive enzymes that act on carbs proteins and fats are secreted into the duodenum.
  67. Clusters of lipids associated with protein that serve as transport vehicles for lipids in blood and lymph
  68. Type of lipoprotein that transports newly digested fat from intestine through lymph and blood
  69. Total of all chemical reactions that go on in living cells
  70. All reactions by which the body obtains and expends the energy from food or body stores
    Energy metabolism
  71. Catabolism:
    break down of body compounds, this reaction usually release energy
  72. When the body does not require energy, the end products of digestion (glucose, amino acids, glycerol, and fatty acids) are used to build body compounds in a process called
  73. Catbolism and anabolism are examples of:
    Energy metabolism
  74. Ancient Ancestors Eating Habits:
    • Rarely used grains (wheat, rice, corn, oats, barely) and this makes up 40-90 perfect of total caloric intake today
    • They ate more meat than we do now
    • More fruits and veggies
    • Less saturated fats
    • Rarely any sugar and if they did it came from honey when available
    • Low sodium for them
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Chapter 3
2012-06-11 00:35:58

Chapter 3
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