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Hypertonic Normal Hypotonic Atonic

Stomach - position and shape 3 muscle layers Greater curvature Lesser curvature Fundic region Cardiac region Corpus or body Pyloric region Pyloric sphincter. Hypertonic Normal Hypotonic Atonic.

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Hypertonic Normal Hypotonic Atonic

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  1. Stomach - position and shape3 muscle layersGreater curvatureLesser curvatureFundic regionCardiac regionCorpus or bodyPyloric regionPyloric sphincter

  2. Hypertonic Normal Hypotonic Atonic Hypertonic Normal Hypotonic Atonic

  3. Contraction of smooth muscle, fluid additions, and enzyme action produce Chyme. • Proximal stomach includes fundus and upper body shows low frequency sustained contractions generating a basal pressure. • Distal stomach includes lower body and antrum develops strong peristaltic waves that increase in amplitude as it approaches the pylorus

  4. Parietal cells • Zymogen cells • Goblet cells

  5. Mucus - Bicarbonate rich, thick • Hydrochloric acid from parietal cells • Proteases - Chief cells Pepsinogen Chymosin (renin ) particularly in young • Other enzymes Lipase GelatinaseHormones - GastrinIntrinsic Factor

  6. Acid Production

  7. Sphincter of Oddi Pancreatic duct Common bile duct

  8. Villi are projections into the lumen covered predominantly with mature, absorptive enterocytes and occasional mucous cells. • Crypts of Liberkuhn are moat-like invaginations of epithelium lined with younger epithelial cells involved in secretion. • Base of crypts are stem cells producing an escalator mechanism via mitosis.

  9. Location of DuodenumProduction of enzymesBrushborderenzymesBrushborder Glycocalyx Unstirred layerEnterokinaseDisaccharidasesAminopeptidase

  10. Coordinated contractions facilitate digestion and absorption bymixing foodstuffs with digestive enzymes and bile Nutrient molecules are dispersed allowing contact with epithelium Chyme is moved down the digestive tube • Following a meal intestine is full of chymeSegmentation contractions chop, mix, and roll Peristalsis propels chyme forward • Inter-digestive state (between meals) tube is largely devoid of contentsHousekeeping contractions move undigestable debris forward Also called Migrating Motor Complex…. Responsible for growling sounds

  11. Transcellular Route: Across the plasma membrane of epithelial cells. Usually larger organic molecules (sugars, amino acids) using receptor proteins. Also includes water. • Paracellular route: Across the tight junctions between cells. Primarily water transport. • Epithelium shows progressive changes in osmotic permeability along length with larger pore sizes initially but better water reabsorption in later parts. Tight junction leak more in ileum.

  12. The single most important process that takes place in the small intestine to make absorption possible is the establishment of an electrochemical gradient of sodium across the epithelial cell boundary of the lumen. • Each enterocyte has about 150,000 sodium/potassium pumps per cell pumping to the intercellular spaces. • This allows each cell to transport about 4.5 billion ions out of each cell per minute. The accumulation of water ultimately is responsible for the absorption of water, amino acids, and carbohydrates.

  13. There is a tight coupling between water and solute absorption. • Sodium is absorbed into the cell by several mechanisms but primary is cotransport with glucose and amino acids. • Absorbed sodium is rapidly exported from the cell via sodium pumps and establishes a high osmolarity in intersitial spaces. • Water diffuses in response to the osmotic gradient established by sodium. Bulk is transcellular . • Water, as well as sodium then diffuses into the capillary blood within the villus.

  14. Colonn

  15. Large Intestine The colon, also known as the large bowel or the large intestine, is an organ of the gastro intestinal tract. It is a hollow tube (about five feet long) that turns feces (liquid waste) into stools during the last phase of Digestion. Aided by enzymes, the stomach churns the foods we eat into a liquid called chyme. The stomach slowly drips the chyme into the small intestine at a rate of about 1/8 of a teaspoon at a time.

  16. Colon ~ Large Intestine • The arrows in the diagram to the right indicate that the chyme is moved up the ascending colon, across the transverse colon, down the descending colon, through the sigmoid colon until it is finally pushed into the rectal sack in the form of a stool. Pressure in the sack stimulates the defecation reflex producing the urge to “go”.

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