Digestive System

Digestive System

Functions
1. Ingestion
2. Digestion
  1. Breakdown of food
  2. Secretion
    1. Exocrine
      1. Do not enter blood
    2. Endocrine
      1. enters blood
    3. Motility
      1. Segmentation
        Mixing
      2. Peristalsis
        Wave movement
3. Absorption
  1. Transport into circulation
4. Storage and elimination
  1. Processes and digest food
Organization
1. Two components
  1. Digestive tract
    1. Stomach
    2. Intestines
  2. Accessory Organs
    1. Liver
    2. Pancreas
    3. Gallbladder
    4. Salivary glands
Oral Cavity
1. Tongue, teeth and salivary glands
2. Mastication
  1. Mixes food with saliva
3. Saliva
  1. Chemical digestion (amylase) lubrication ,antibacterial
4. Deglutition
  1. Swallowing
    1. Medulla Oblongata
      1. Coordinates process
  2. Buccal Phase
    1. Bolus formation and movement
  3. Pharyngeal Phase
    1. Movement of uvula to close off nasopharynx
    2. Elevation of epiglottis
    3. Reflection of glottis
    4. Closure of glottis
  4. Esophageal phase
    1. Opening of upper esophageal sphincter
      1. Peristalsis
    2. Opening of lower esophageal sphincter
Esophagus
1. Connects pharynx to stomach
  1. Muscular Externa
    1. Upper 3rd
      1. Skeletal muscle
      2. Middle 3rd
        Muscles of skeletal & smooth
        Terminal portion
        Smooth
  2. Passes through diaphragm via esophageal hiatus
  3. Sphincter: UES and LES
2. Peristalsis
  1. Propels food thru GI tract
  2. GERD
Stomach
1. Most distensible part of the GI tract
  1. Empties into intestines
2. Function
  1. Food storage
  2. Absorption of NSAIDS and alcohol
  3. Protein digestion
  4. Bacteriostatic
  5. Moves food (chyme) into intestines
3. Regions
  1. Cardia
  2. Fundus
  3. Body
  4. Pylorus
4. Organization of stomach Mucosa
  1. Gastric pits
  2. Gastric glands 4 types
    1. Exocrine Function
      1. Mucus cells
      2. Chief cells
        Manufacture inactive pepsinogen
      3. Parietal cells
        produce HCL and Inssintrcit factor
        Activate Pepsinogen
        Denature protein ,exposing peptide bonds
    2. Endocrine Function
      1. Somatostatin
        Inhibits gastric function
      2. Gastrin
        Stimulates production of HCL acid production
      3. Ghrelin
        Hormone that stimulates appetite
      4. Histamine
        Stimulates acid production

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	Created by Susy Sanchez over 11 years ago