digestion

  1. intracellular digestion
    oxidation of glucose and fatty acids for energy
  2. extracellular digestion
    process by which glucose and fatty acids are obtained from food, occurs in lumen of alimentary canal (mouth to anus)
  3. absorption
    the transport of products of digestion from digestive tract into circulatory system for distribution
  4. direction of food travel
    oral cavity (mouth), pharynx, esophagus, stomach, small intestine, large intestine, rectum (feces stored unless release)
  5. enteric nervous system
    neurons present in the walls of the digestive tract and trigger peristalsis of the gut tube
  6. what are salivary glands innervated by?
    parasympathetic nervous system
  7. salivary amylase
    hydrolyzing starch into smaller sugars
  8. pharynx is divided into three parts
    • nasopharynx, oropharynx (back of mouth) and laryngopharynx (above the vocal chords)
    • food prevented from entering larynx by epiglottis
  9. esophagus
    • top 1/3 is skeletal muscle (voluntary motor control)
    • middle mixed
    • bottom smooth muscle (involuntary)
  10. what kind of glands are in fundus and body?
    gastric glands (mucous cells, chief cells and parietal cells)
  11. what kind of glands are in antrum and pylorus
    pyloric glands
  12. mucous cells
    produce bicarbonate rich mucus to protect wall from acidic environment
  13. gastic juice
    • chief cells secrete pepsinogen¬†
    • parietal cells secrete H (cleave pepsinogen to pepsin, also secrete intrinsic factor)
  14. pyloric glands
    • contain G cells that secrete gastrin, a peptide hormone
    • induces parietal cells to secrete more H, and signals the stomach to contract, mixing its contents.
  15. the parts of the small intestine
    • duodenum (digestion)
    • jejunum (absorption)
    • ileum (absorption)
  16. brush border enzymes
    at the luminal surface of cells liming the duodenum and break down dimers and trimers into monomers
  17. food leaves the stomach through what to enter the duodenum
    pyloric sphincter
  18. what is necessary for carbohydrates to be used?
    • need to be broken down to monosaccharides for absorption
    • di and tripeptides can be absorbed across the small intestine wall
  19. secretin
    • regulates pH by reducing H from parietal cells and increasing bicarbonate secretion from pancreas
    • also an enterogastrone (hormone that slows motility through the digestive tract)
  20. enteropeptidase
    activation of trypsinogen to trypsin, pancreatic protease
  21. CCK (cholecystokinin)
    • secreted in response to entrance of chyme into duodenum
    • stimulates the release of bile and pancreatic juices, also acts in the brain to promote satiety
  22. bile
    • digest lipids, emulsify facts, creates micelles, facilitate lipase action
    • amphiphatic
  23. pancreatic juice
    • pH 8.5 for those enzymes that work best in that pH
    • digest all three types of nutrients: carbohydrates, fats and proteins
  24. endocrine functions of pancreas
    release of insulin, glucagon and somatostatin
  25. exocrine functions of pancreas
    • made of acinar cells that produce pancreatic juices
    • amylase (breaks carbs)
    • trypsinogen breaks down proteins
  26. bile ducts connect the liver with what
    gallbladder and small intestine
  27. functions of liver
    • produces bile
    • create glycogen and stores fats and reverse those reactions to produce glucose
    • detox
    • synthesis of albumin and clotting factors
  28. bilirubin
    • byproduct of breakdown of hemoglobin
    • travels to the liver where it is conjugated (attached to a protein) and secreted into bile for excretion
    • when liver cannot excrete it, jaundice occurs
  29. gallbladder
    stores and concentrates bile
  30. digestion in the mouth contains what enzymes?
    amylase (break down starch) and lipase
  31. digestive enzymes in the stomach
    pepsin
  32. digestive enzymes produced in the pancreas
    trypsin, chymotrypsin, carboxypeptidases A and B, amylase, lipase
  33. digestive enzyme in gallbladder
    bile miclles
  34. digestive enzymes in small intestine (brush border)
    sucrase, lactase, maltase (break down carbs), dipeptidases, amino peptidases (break down proteins
  35. what does bile consist of?
    bile salts (amphipathic molecules), piments (bilirubin from breakdown of hemoglobin) and cholesterol
  36. where is bile produced, stored, and serves its function
    produced in the liver, stored in gallbladder and serves function in duodenum.
  37. what is in the middle of each villus in the small intestine
    capillary bed for absorption of water soluble nutrients and lacteal (lymphatic channel that takes up fats for transport to the lymphatic system)
  38. how does simple carbs and amino acids diffuse from the epithelial cells lining the small intestine into the capillaries?
    via concentration gradient, blood always has lower concentration of monosaccharides and amino acid than inside the epithelial cells
  39. chylomicrons
    triglycerides and esterified cholesterol from small intestine are packaged and enters the lymphatic system
  40. transcellularly and paracellularly
    water can travel across cell membrane and also squeeze between cells to reach blood
  41. large intestine
    water absorption, consists of cecum, colon and rectum
Author
xijunzhu
ID
317927
Card Set
digestion
Description
mcat
Updated