Digestion and Excretory

  1. Digestive path
    mouth - esophagus - stomach - small intestine - large intestine - rectum - anus
  2. digestion starts where, and how?
    in mouth

    alpha-amykase in saliva
  3. alpha amylase does what?
    degrades starch into polysaccharides

    increases surface area allowing more enzymes to work on food molecules
  4. How are food molecules pushed to esophagus?
    peristaltic motion

    (smooth muscle)
  5. What is primary function of the stomach?
    mixes and stores food - reduces it to chyme
  6. exocrine glands in stomach
    begins protein digestion with pepsin

    low pH
  7. What is the pH of the stomach
  8. 4 cell types in the stomach
    mucous cells

    chief cells

    parietal cells

  9. What do mucous cells do?
    line stomach wall and exocrine glands

    allows food to slide along without damaging the cell
  10. What are mucous cells composed of?
    sticky glycoproteins and electrolytes
  11. What do chief cells do?
    secrete pepsinogen
  12. What is pepsinogen? What is it activated by? What does it do?
    pepsinogen = zymogen of pepsin

    activated by low pH of the stomach

    protein digestion
  13. What do parietal cells do?
    secrete HCl

    lowers pH of stomach and raise blood pH
  14. What are parietal cells stimulated by?
    release of gastrin
  15. What do G-cells do?
    secrete gastrin
  16. What is gastrin, and what does it do?
    gastrin = peptide hormone

    absorbed into the blood - stimulates parietal cells
  17. What are the major hormones that affect secretion of stomach juices?
    acetylcholine, gastrin, and histodine
  18. 3 parts of the small intestine and their functions
    duodenum (most digestion)

    ileum (absorption)

    jéjunum (absorption)
  19. wall of small intestine contains what, and why?

    increases surface area

    (brush border in light microscope)
  20. What does lysozyme do?
    regulates bacteria within the intestine
  21. Where does chime move to after the small intestine?
  22. Main function of the pancreas
    acts as an exocrine gland

    secretes bicarbonate ions
  23. What is the pH in the small intestine and how?
    pH = 6

    bicarbonate ions released from small intestine
  24. Which enzyme activates all other zymogen forms released from the pancreas
  25. major enzymes released from the pancreas and their function
    trypsin and chymotrypsin = degrade proteins

    amylase = polysaccharides into di and trisaccharides

    lipase = degrades fat (triglycerides)
  26. Trypsin degrades proteins into small polypeptides. How are they reduced to amino acids?
    when they reach the brush border
  27. bile - where is it produced, where is it stored, what does it do?
    produced in liver

    stored in gull bladder

    emulsifies fat = increases surface area
  28. What happens to bile after it emulsifies fat molecules?
    reabsorbed by small intestine and transported back to liver
  29. Primary function of large intestine
    water reabsorption
  30. How is glucose absorbed into cells?
    secondary active transport

    down Na+ gradient
  31. How is fructose absorbed into cells
    facilitated diffusion
  32. How are proteins absorbed into cells?
    co=transport down Na+ gradient
  33. Do we want a high or low intracellular amino acid concentration?
  34. When fats are absorbed, they are first converted into what, how?
    converted to fatty acids to brush border

    diffuse through enterocyte membrane

    return to triglycerides at smooth ER
  35. thoracic duct
    delivers lymph to venous circulation

    delivers fat to the blood
  36. Where does liver receive blood from?
    capillary beds of the intestines, stomach, spleen, pancreas
  37. Why is there a secondary blood supply to the liver?
    sent to oxygenate it
  38. Where does all of the blood received by the liver move to?
    through flattened spaces

    leads to vena cava
  39. liver funcitons (5)
    • 1. blood storage and filtration
    • 2. carb, fat, and protein metabolism
    • 3. detoxification
    • 4. erythrocyte destruction
    • 5. vitamin storage
  40. When liver mobilizes fat or protein for energy, what happens to blood acidity levels?
  41. Kidney (path)
    afferent/efferent arterioles - glomerulus - Bowman's capsul - proximal convulated tubule - loop of Henle - distal convulated tubule - collecting duct - bladder/urethra
  42. uterer and urethra
    uterer = carrries urine to the bladder

    urethra = drains the bladder
  43. afferent and efferent arterioles
    afferent = carries blood into nephron

    efferent = carries filtered blood out of nephron
  44. what is the renal capsule
    glomerulus and Bowman's capsule
  45. how does filtrate move from glomerulus to Bowman's capsule?
    hydrostatic pressure
  46. What goes on in proximal tubule?
    secondary active transport

    wanted material is reabsorbed into capillary system
  47. glucose reabsorption in proximal tubule
    in a healthy adult, glucose is completely reabsorbed
  48. Is insulin absorbed or excreted?
  49. loop of Henle - location
    crosses border from renal cortex into renal medulla
  50. descending loop
    only permeable to water

    • H2O leaves loop and into medulla
    • (because medulla is salty)
  51. filtrate osmolarity in descending loop
    high osmolarity

  52. ascending loop
    only permeable to salts

    slats leave filtrate
  53. distal tubule
    reabsorbs Na+ and Ca2+

    secretes K+ , H+ and HCO3-
  54. collecting duct
    collects waster products of multiple nephrons

    transports waste to bladder
  55. ADH
    increases permeability of water - water is absorbed into medulla (since it's salty)

    Always Digging Holes
  56. Where is the urine concentrated?
    descending loop of Henle

    mostly in collecting duct
  57. What does aldosterone do?
    increases Na+ and K+ membrane transport proteins

    so it increases Na+ absorption and K+ secretion
  58. Juxttaglomerular Apparatus
    monitors filtrate pressure in distal tubule
Card Set
Digestion and Excretory
Digestive and Excretory Systems