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30 Cards in this Set
- Front
- Back
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Histology Of Ailmentary Canal |
1. Mucosa - Epithelium Lining - Lamina Propria - Muscularis Mucosa 2. Submucosa 3. Tunica Muscularis 4. Serosa
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Mucosa |
- Epithelium Lining Simple Columnar shape; absorption; prevents autodigestion - Lamina Propria Loose connective tissue; support + nutrition; very cell dense; capillaries and lymphatics - Muscularis Mucosa two thin layers of smooth muscle; propells nutrients |
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Submucosa |
Innervated by ANS for peristalsis; Meissener's Plexus - tells glands to secret and muscualris mucosa to contract; Absorption into blood stream occurs here |
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Tunica Muscularis |
- All smooth muscle (except for esophagus) - Two layers (except for stomach) - Propulsion - Auerbach's (Myenteric) Plexus - control GI motility - (forms sphincters) |
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Tunica Serosa |
Outermost covering of walls of organs to reduce friction; Binds structures together |
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Functions of Liver |
- Carbohydrate metabolism - Protein Metabolism - Lipid (fat) metabolism\ - breakdown of RBC/Hemoglobin to Bile - Detoxification - toxins to kidney for execretion |
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Liver Lobule |
Hexagonal shaped functional units. Each has a Central Vein in the center (collects blood after it is processed in sinusoids, and drains into hepactic vein to go back into circulation).
Each also has a portal triad (Hepatic artery brings oxygenated blood to liver, oxygen is used. Portal vein brings deoxygenated, nutrient rich blood from intestines. These two tubes drain into central vein).
Bile ducts take bile produced in the liver, and transport to the gallbladder for storage.
The liver sinusoids have heptacytes that extract nutrients out |
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Creation of Bile |
RBC's are broken down by Kupferr cells in liver Sinusoids. The hemoglobin is split into Bilirubin and Iron. Bilirubin converts Albumin. This is processed into Bile salts and then Bile.
Transported via Bile ducts to Gallbladder for storage.
Blockage of these ducts leads to Jaundice |
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Carbohydrate Absorption in GI Tract |
Amylase enzyme secreted by Pancreas breaks down carbs into mono and disaccharide forms.
Absorption coupled with Na+ down conc. grad
Transported to liver via hepatic portal vein for absorption by liver sinusoid cells |
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Protein Absorption in GI Tract |
- Acid, Pepsin, and Trypsin released via Pancreas - Broken into AA's and small peptides for absorption - coupled with Na+ down conc grad. - transported to liver via hepatic portal vein
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Fat + Cholesterol |
- Bile makes it water soluble - Broken from TG to fatty acids and monoglycerides via Lipases (enzyme from Pancreas) - SI absorbs the lipids
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Absorption of Cholesterol |
1. TG broken down by Lipase into FFA and Monoglycerides 2. These two coupled with apoproteins to make Chylomicron. 3. Chylomicron put into vessels for exocytosis into lympatic system 4. From lympatic system, it moves to venous system
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Cholesterol normal values |
- Normal = 200 - At risk = >240 with LDL>160 or HDL<35
- LDL is bad, plaque causing cholesterol (athersclerosis)
- HDL is good, LDL removing cholesterol. Stores it properly |
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Treatment for High Cholesterol |
1. Cholestyramine: Binds to resin, forms complexes that are excreted 2. Statins: Decrease LDLs and increase HDLs 3. Ezetimibe: Reduces LDL |
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Daily Water values |
We take in about 8200 ml, reabsorb 8850 ml
- only excrete 150ml in feces - Water is absorbed until isoosmtic with plasma - Too much water or too much ADH leads to water intoxication
- Seawater causes problems for body due to the not being about to digest MgSO4 salts |
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Control of Digestion |
Long Reflex - Connects different regions of GI tract together. Vagus nerves carries messages from brain to GI tract. Feedforward reflexes also occur here.
Short Reflex Innervations - GI tract activated by ENS (digestion brain). Can be stimulated by smells, distention, etc. ENS actives glands and muscle in GI tract thru short innervation. |
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Physiology of Swallowing |
1. Food taken into mouth and saliva released 2. Tounge pushes food back, causes medulla swallowing center activation (controls muscle) 3. Larynx closes trachea, nasopharax closes 4. Upper esophageal sphincter opens, food moves down, and it closes. 5. Lower Esophageal sphincter opens
Respiration briefly inhibited |
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Stomach Anatomy |
- Secretion and absorption - Four parts to stomach 1. Cardiac (with sphincter) 2. Fundus 3. Body 4. Pyloris (with pylorus sphincter) - Has a mucosa - Folds called Rugae. - Heartburn occurs due to acid reflux in cardiac sphincter - Tunica Muscularis has 3 layers (instead of 2 in esophagus) - Pyloric Sphincter controls food from stomach to duedenum in SI |
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Stomach Mucosa cells |
> Muscosa Neck Cells - mucous production (prevent damage) > Parietal Cells - make HCl/Gastric Acid; active pepsin for protein digestion; secrete intrinsic factor which helps absorb VitB12** > Chief Cells - Digestion protein (pepsinogen) and fats > G cells - stimulate parietal cells to make acid. Activated by food released in stomach >Enterochromaffin cells - Histamine production leads to parietal cell stimulation > D cells - Somatostatin production to inhibit acid production |
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Gastric Acid Production cascade |
1. CO2 and H20 enter parietal cells, react with Carbonic anhydrase to make H2CO3. Disassociates to H+ and HCO3- 2. HCO3- moves to blood stream and Cl- moves into cells 3. cAMP stimulates H+/K+ kinase pump to move H+ into cells and K+ out. 4. H+ and Cl- make HCl
Histamine activates cAMP PGE2 deactivates cAMP |
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Acid production Inhibition |
- ACH antagonists - i.e. Atropine - Histamine blockers - Gastrin Blockers - Omeprazole blocks H+/K+ pump - High acidity inhibits Gastrin release = High protein meals stimulate acid production - Empty Stomach = highly acidic --> acid production decreased to cope |
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Ulcers |
Hypersecretion of acid in stomach, or lack of production from Tunica Mucosa
Treatment = histamine blockers |
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Small Intestine Functions |
- Enzyme driven digestion from Pancreas - Emulsification of fats via bile - Absorption of nutrients - secretions of hormones - has a basic pH |
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Small Intestine Parts (3) and Cell Types (4) |
Parts 1. Duodenum - digestive enzymes enter from pancreas; connects stomach to SI 2. Jejunum - Digestion/absorption occur here 3. IIeum - connects SI to LI
Four Cell types Absorptive, Goblet (secret mucous), Enterendocrine (hormones), Paneth (antibacterial) |
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Tunica Mucosa of Small Intestine |
1. Simple Columnar Epithelium with microvilli 2. Arranged in villi 3. Plica (folds)
- All of these increase surface area and absorption - Crypts of Lieberkuhn are at base of folds, and contain the enterendocrine and paneth cells
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Small Intestine Hormone Production |
From Enterendocrine Cells
1. GIP: triggered by duodenal filling and acid, released due to carbs in meals, inhibits GI motility, gives time for absorption 2. CCK-PZ: Release due to proteins/fat fillign duedenal, stimulates Gallbladder release of bile, stimulates enzyme secretion from Pancreas 3. Secretin: Release due to acid in duedenum, stimulates bicarbonate to neutrilize HCl, inhibits acid porduction and motlity
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Movements of Small Intestine |
1. Segmentation - back of forth mixing allows for absorption via contact with villi and microvilli 2. Peristalsis - forward propulsion of chyme |
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Pancreas functions (Exo and Endo) |
- Exocrine functions: Acinar cells produce pacreatic juice, which contains HCO3- to neutrilze acid in the SI (juice released thru duedenom). Enzymes from the Pancreas are also released into the SI for digestion here - Endocrine functions: Hormonal blood sugar regulation (insulin and glucagon hormones) - Bile duct from live lobules meets Pancreatic duct to form "Ampulla of Vater", which flows into SI. Sphincter of Oddi controls its release |
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Large Intestine |
- Anchored to back wall by Mesocolon Mesentary. - Absorbs water and electrolyes, but very little - Vitamin production K - Large peristalsis movement moves poop out - Three parts: Cecum, Colon, Rectum - Has pouches called "Haustra"
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Large Intestine conditions |
- Diverticulitis: diet lacks bulk - causes infection - Hirschsprung's Disease: Feces back up due to constricting LI - Hemmorroids: Varacose veins in anal canal
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