Adult 1 Unit 4 GI

  1. GI System Blood Supply
    • Receives 25-30% of cardiac output
    • Blood from GI track returns to → Portal Vein →Liver → Inferior Vena Cava→ Heart

    • GI Tract receives its arterial blood from:
    • Upper = Splenic Artery
    • Small Intestine = Hepatic & Superior MesentericArteries
    • Large Intestine = Superior & Inferior Mesenteric Arteries
  2. GI System Innervated By Autonomic Nervous System
    • Sympathetic nervous system shunts blood to heart & brain (not GI)
    • Parasympathetic nervous system/vagal stimulation over the GI system
    • Voluntary control over:
    • Swallowing – upper esophageal sphincter
    • Defecation – external anal sphincter
  3. Stomach
    • (food stays 4 hours)
    • Liquefies food into chyme (creamy, semi-fluid material) as it mixes with gastric enzymes, HCL, &pepsin (Protein digestion begins)

    • Mechanical Digestion churning of the food to help break into smaller particles
    • Absorbs small quantities of food (water, glucose);
    • Intrinsic factor synthesized by cells of stomach combines with Vit. B12 so it can be absorbed in the ileum
    • If no Vit. B12=pernicious anemia;

    Pyloric sphincter allows a small amount of chyme to enter duodenum at a time
  4. Liver Functions:(largest organ)
    • Carb, Protein & FatMetabolism
    • Detoxification
    • Synthesize clotting factors
    • Bile production & excretion
    • Glucose (Glycogen) storage
    • Breakdown old RBC, WBC, hemoglobin &bacteria (Kupffer cells)
  5. Gallbladder
    • Biliary Tract
    • Gallbladder- concentrates & stores bile (removes water) Holds 45-90 cc of bile

    Ductal system- hepatic ducts merge with cystic duct from Gallbladder to form Common Bile Duct emptying into duodenum
  6. Bilirubin
    Pigment from the breakdown of hemoglobin & is constantly produced

    Unconjugated (until mixed with glucuronic acid in the Liver & is not water soluble)

    Conjugated (is water soluble & is excreted in the bile) Needed for fat emulsion and digestion
  7. Pancreas
    Exocrine Gland-Pancreatic Enzymes transported to small intestines (duodenum)

    Endocrine Gland - Islets of Langerhans produce Insulin (betacells)
  8. Recommended Balance of Carbohydrates, Proteins and Fats
    • Carbohydrates(50-55% of caloric intake)
    • Proteins(15-20% of caloric intake)
    • Fats(30% or less of caloric intake with< 10% saturated)
  9. GI Gerontologic Considerations
    • Teeth wear down, periodontal disease, lose teeth (no appetite)
    • Decrease in:
    • Taste buds, smell, salivary secretions,GI motility, & HCL acid
    • Delayed emptying of stomach
    • Increase in gallstones
    • Decrease in dietary fiber/fluid
    • Increased constipation
Card Set
Adult 1 Unit 4 GI
Adult 1 Unit 4 GI