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Physiology of Digestion - Coggle Diagram

- - - - Protease (typsinogen, chymotrypsinogen, pro-elastase, pro-carboxypeptidase, kallikreinogen), Lipase Amylase
      - Enterokinase activates trpsinogen to trpsin which activates multiple other enzymes
- - - - Absorbed in length of small bowel with other lipids via micelles and chylomicrons into lymphatics
      - Absorbed directly into bloodstream via passive diffusion
      - Vitamin K produced by colonic bacteria absorbed in colon
    - - Absorbed in distal ileum, malabsorption may lead to gastric atrophy, pancreatic insufficiency, ileal disease
  - - - Absorbed in non-heme form, then gastric acid and brush border convert to ferrous iron, which is bound to gastroferrin and absorbed
    - - Absorbed via a vtamin D dependent process
- - - - Thought, smell, taste of food stimulates salviary, gastric and pancreatic secretion
    - - Stomach distension -> neural refelxes -> Acid,pepsin
      - Partially digested protein -> Gastrin -> Acid secretion
    - - Chyme in duodenum _. release of digestive hormones, increased small bowel motility, inhibit enterogastric reflexes to allow digestion in coordiante manner
  - - - Enteric nervous system responsible for regulation fo GIT motility and secretion
        
        Myenteric Plexus regulates motility
        
        Submucosal plexus regulates secretion + bloodflow
      - Interstitial Cells of Cajal
        
        Pacemaker cells present throughout GIT to generate spontaneous electric slow waves that spread to smooth muscle
      - Hypothalamus
        
        Feeding/satiety centers in hypohtalamus regulate apetite, and receive signals from cortical centers and periphral mediators
    - - Acetrylcoline
        
        Stimulatory molecule secreted by autonomic and enteric neurves to promote motility and secretion
      - Nitric Oxide
        
        Inhibits smoooth msucle, and secreted during fasting state to reduce peristalsis
      - Vasoactive intestinal polypeptide
        
        Secreted by myenteric and submucosal plexus during fed state to inhibit ciruclar smooth muscle to accomodate food and perislsis
        
        Stimulates secretion from mucosal tglands and vasodilation to absorb transport
      - Epinepherine
        
        Secreted during times of acute stress to seduce GIT function
      - Gastrin
        
        Stimulatory hormone released from G cells to stimulte parietal cells, ECL cells, antral smooth muscle, and pancrease
      - CCK
        
        Released in response to food in duodenum, relaxes sphincter of Oddi to allow bile/pancreatic flow, stimulates pancreas to release enzymes, induces satiety
      - Secretin
        
        Stimulates production of bicarb to neutralize stomach acid
      - Somatostatin
        
        Inhibits GIT motility and decretion in response to digestive processes