Physiology of Digestive System

  1. What is the primary function of the digestive system?
    To bring essential nutrients into the body
  2. What 7 mechanisms are used to accomplish the primary function of the digestive system?
    Ingestion, Digestion, Motility of GI wall, secretion of enzymes, Absorption, Elimination, Regulation
  3. What is ingestion?
    The process of taking food into the body
  4. What is digestion?
    The breakdown of nutrients
  5. What is the function of the motility of the GI wall?
    physically breaks down large chunks of food and moves food along tract
  6. What does digestive enzymes do?
    Allow chemical digestion
  7. What is absorption?
    movement of nutrients through the GI mucosa 
  8. What is elimination?
    Excretion of material not absorbed
  9. What is regulation?
    coordination of various functions of the digestive system
  10. The digestive tract is functionally an...
    extension of the external environment; not truly part of internal environment until absorbed
  11. How many microbes are throughout the digestive system?
  12. What is mechanical digestion?
    movements of the digestive tract
  13. What is mastication?
    process of chewing food
  14. What is the first part of mechanical digestion?
    To change large food particles into minute particles, facilitating chemical digestion
  15. What is the 2nd step in mechanical digestion?
    To churn contents of the GI lumen with the surface of the intestinal mucosa, facilitationg absorption
  16. What is the 3rd part of mechanical digestion?
    To propel food along the alimentary tract for elimination
  17. What is Deglutition?
    the process of swallowing
  18. How many stages of deglutiition are there?
  19. What is the first step of deglutition?
    • The oral stage (mouth to oropharynx): 
  20. What is the 2nd step of deglutition?
    • Pharyngeal stage (oropharynx to esophagus): 
  21. What is Peristalsis and segmentation?
    2 main types of motility produced by the smooth muscles of the GI tract.
  22. What is peristalsis?
    wavelike ripple
  23. What is segmentation?
    Mixing movement
  24. What is gastric motility?
    emptying the stomach takes approx. 2-6 hours. Food is churned and mixed with gastric juices to form chyme
  25. What does chyme pass through?
    pyloric sphincter
  26. After leaving the stomach, how long does it normally take chyme to pass thru the small intestines?
    approx 5 hours
  27. Absorption occurs thru...
    villae and microvillae in small intestines
  28. What is chemical digestion?
    Changes in chemical composition of food as it travels thru the digestive tract.
  29. What kind of digestion results in hydrolysis?
    Chemical digestion
  30. Chemical digestion enzymes function optimally...
    at a specific pH
  31. What happens to sugars when they aren't broken down?
    They ferment
  32. Carbs are ....
    saccharide compounds
  33. Protease break down proteins into...
    amino acids
  34. What are amino acids?
    building blocks of proteins, cell membranes and etc
  35. What does fat digestion entail?
    Fats must be broken down by bile in small intestine before being digested
  36. What is the main fat-digesting enzyme?
    Pancreatic lipase
  37. What 2 things are the result of fat break down?
    glycerol and ketone bodies
  38. What has to be coded in order to be digested?
  39. Salivary glands secrete...
  40. What enzyme begins digestion of starches?
  41. What increases the pH for optimal amylase function?
    Sodium Bicarbonate
  42. What is secreted by parietal cells?
    Hydrochloric acid
  43. What is secreted by gastric glands?
    Gastric juices
  44. What actively releases hydrochloric acid into gastric juices?
    Hydrogen- potassium pumps
  45. What is another name for hydrogen pumps?
    Proton pumps
  46. HCl is one of the primary acids in...
  47. Prilosec is considered a ...
    proton- pump inhibitor because it turns off the pumps that produce gastric acid
  48. What secretes the intrinsic factor?
    parietal cells
  49. What does the intrinsic factor do?
    protects vitamin B12 and later facilitates absorption
  50. What must happen for B12 to pass into the blood stream?
    It has to be paired with an intrinsic factor
  51. What secretes pancreatic juice?
    acinar and duct cells of the pancreas
  52. What are proteases?
    enzymes that digest proteins and polypeptides
  53. Which enzymes digest emulsified (broken down) fats?
  54. Which enzymes digest nucleic acids such as DNA and RNA?
  55. Where is bile secreted and then stored?
    secreted in the liver and stored and concentrated in gallbladder
  56. What is secreted by the intestinal exocrine cells?
    Intestinal juice
  57. Olfactory and visual stimuli come from...
    the smell and sight of food
  58. Gastric secretion has how many phases?
  59. Pancreatic secretion is stimulated by...
    several hormones released by intestinal mucosa
  60. Most absorption occurs in...
    the small intestine
  61. What is gastric bypass?
    bypassing the small intestine which prevents food from being absorped
  62. For absorption to happen, food has to be...
    absorbed thru the cell wall of the duodenum
  63. What is elimination?
    the expulsion of feces from the digestive tract
  64. What is defecation?
    the act of expelling feces
  65. What is constipation?
    contents of lower part of colon and rectum move at a slower than normal rate
  66. What is diarrhea?
    result of increased motility of the small intestine, causing decreased absorption of water and electrolytes and a watery stool
  67. The colon only absorbs...
  68. Oxygen for digestive activity depends on... 
    proper functioning of the resp and circulatory systems.
Card Set
Physiology of Digestive System
A&P Chapter 26