Physio II

  1. What are the Exocrine secretions in the Stomach and what is there location?
    • Surface cells- Mucus, HCO3
    • Neck cells- Mucus, HCO3
    • Parietal cells- HCL, Intrinsic factor
    • Chief cells- Pepsinogen and gastric lipase
  2. What are the endocrine secretions in the stomach?
    From andtral D and G cells- Gastrin and Somatostatin.
  3. What are the three phases of the digestive period?
    Cephalic- Gastric- Intestinal-
  4. What is the Cephalic phase?
    Sensory receptors causes the increase in Acid secretions due to efferent preganglionic vagal fibers that activate the ENS fibers.
  5. What is the gastric phase?
    • Three parts:
    • Intragastric buffering by food- pH rises slightly
    • Distension-activates Vago Vago reflexes that effect ENS to secrete Gastrin and lower pH.
    • Chemical stimulation- Ca,Caffeine,Alcohol and protein stimulate acid secretions.
  6. What does GRP do?
    It stimulates Gastrin cells to release gastrin in to the blood -->leads to acid secretion.
  7. What is the role of CCK and Secretin?
    In the intestine, they responed to high protein nad H+ levels and cause the release of the inhibitory hormone Enterogastrone which decreases gastrin release.
  8. Name some aggresive factors of the Mucosal barrier.
    HCL/Pepsin, Bile, H. Pylori (gram Neg in the antrum), alcohol and nicotine and aspirin(decrease the production of prostaglandins which causes an increase in acid)
  9. Name some protective factors.
    Mucus, HCO3, Blood flow (washes H+ away), Membrane integrity and fast membrane repair.
  10. What is intrinsic factor? where is it secreted?
    • It is a glycoprotein that is secreted by by the parietal cells in reponse to ACh gastrin or histamine.
    • Is essential for B12 Absorption in the ileum.
  11. Role of R-protiens and IF in B12 absorption.
    • In the stomach- B12 binds to R protein.
    • In the intestin trypsin causes the b12 to release R and grab IF.
    • IF carries B12 to the ileum where it binds to a recepter, is internalized.
    • B12 then releases IF and binds to transcobalamin II
Card Set
Physio II
Physio II