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53 Cards in this Set
- Front
- Back
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What are the four layers of the digestive tract from outer to inner?
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Serosa (visceral peritoneum), muscularis externa, submucosa, mucosa.
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What are the three layers of the digestive mucosa?
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Epithelium, lamina propia, muscularis mucosae
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What are the characteristics of the epithelium of the digestive tract?
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Varies depending on location.
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What is the epithelium of the small intestines?
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Columnar specialized for digestion and absorption.
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What is the lamina propria?
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Connective tissue layer of mucosa, rich in elastic fibers.
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What is the muscular is mucosae?
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Smooth muscle of the mucosa
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What are the characteristics of the submucosa of the digestive tract?
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Contains neurons of Meissner's plexus and is rich in blood vessels and lymphatics.
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What are the characteristics of the muscular is externa of the digestive tract?
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Main muscle coat of smooth muscle of both inner circular and outer longitudinal, and neurons of Auerbach's plexuses.
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What are the characteristics of the serosa of the digestive tract?
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AKA visceral peritoneum, mostly dense connective tissue.
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What is the enteric nervous system?
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Composed of Auerbach's plexuses and Meissner's plexuses, many neurons. Third branch of the autonomic nervous system.
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What are two special structures of the peritoneum?
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Mesentery that connects small intestine to posterior abdominal cavity. Carries nerves, lacteals, blood vessels.
The greater omentum is anterior to abdominopelvic cavity. Stores fat. Many macrophages. |
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What are the layers of the teeth from outer to inner?
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Enamel (calcium phosphate), dentine, dental pulp, periodontal ligament.
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What is the anatomy of the tongue?
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nerves, taste buds, blood vessels, lymphatics. Mostly skeletal muscle. Mucous membrane with serous glands. Covered with lingual papillae. Attached to hyoid bone and mandible. Lingual tonsils at rear of tongue.
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What are the functions of saliva?
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Calcium and phosphate for teeth, moistens, solvates, salivary alpha amylase for carbohydate digestion, immune secretions, pH buffer.
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What are the three salivary glands?
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Parotids, submandibular, sublingual.
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How are salivary glands innervated?
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Parasympathetic cholinergic nerves cause vasodilation, secretion, and smooth muscle contraction.
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What is the digestive importance of the pancreas?
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Secretes the majority of the enzymes needed for digestion of carbohydrates, lipids, proteins. Alkalinity also helps neutralize stomach acid in the small intestine.
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What are the five important categories of components of pancreas juice?
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Bicarbonate, proteases, amylases, lipases, nucleases
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What proteases are found in pancreatic juice?
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Trypsin, chymotrypsin, carboxypeptidase A, carboxypeptidase B.
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What carbohydrate digesting enzyme is found in pancreatic juice?
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Pancreatic alpha amylase.
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What nucleases are found in pancreatic juice?
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DNAse, RNAse.
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How does the nervous system regulate the pancreas?
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Pancreatic juice secretion stimulated by parasympathetic via vagus nerve and inhibited by sympathetic.
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What two hormones affect the pancreas and where is the origin for each hormone?
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Cholecystokinin from the small intestine and secretin from the small intestine.
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What is pathway of action for cholecystokinin?
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Fatty acids, monoglycerides, peptides, and amino acids stimulate its release (carbs don't) from the small intestine increases enzymatic concentration of pancreatic juice and stimulates gallbladder contraction to release bile.
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What is the pathway of action for secretin?
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Low pH in the small intestine stimulates it's release which stimulates pancreas to secrete bicarbonate and slows stomach emptying.
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What is the anatomy of the pancreas?
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Exocrine secretions from acinar cells that form hollow acini. Secretions fill acini which empty into ductules to ducts to main pancreatic duct.
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What duct merges with the main pancreatic duct?
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Bile duct.
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What controls the rate of discharge from the bile duct into the duodenum?
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Sphincter of Oddi.
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What are the ten main functions of the liver?
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1. Kuppfer cells phagocytize
2. Metabolic processes 3. Hepatocytes produce bile 4. Secretes somatomedin via somatotropin (growth hormone) 5. Stores substances such as glycogen, lipid droplets, vitamin A, B12 6. Manufactures most plasma proteins 7. Detoxifies via excretion into bile 8. Deaminates amino acids to form urea 9. Metabolizes cholesterol 10. Synthesizes 25-hydroxycholecalciferol |
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What is purpose and origin of bile?
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From hepatocytes in the liver, it is important in lipid digestion and cholesterol excretion (along with certain other substances).
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What is the functional unit of the liver?
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Hepatic lobule.
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Blood from what organs join to form the hepatic portal vein?
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Pancreas, GIT, spleen.
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What are hepatocytes organized into?
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Hepatic lobule.
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Blood from hepatic arterials flows to hepatic lobule at what part of the lobule?
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The corners.
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Blood from hepatic veins enters hepatic lobule at what part of the lobule?
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The corners (right next to hepatic arterials).
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How does the blood leave the hepatic lobule?
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The central vein.
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How does blood from portal vein and hepatic arterials enter the central vein?
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Via the sinusoids which serve as a channel.
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How does excess plasma and bile leave hepatic lobule?
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Via the bile canaliculus.
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What do bile canaliculus merge to form?
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Common hepatic duct.
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The hepatic duct flows to what?
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The gallbladder.
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What is the nervous system control of the gallbladder.
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Parasympathetic through the vagus initiates gallbladder contraction.
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How do patients with cholecystectomy (gallbladder removal) usually adapt to maintain proper digestion?
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Bile duct often dilates thus lending a minor storage ability.
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What are the three functions of bile?
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Excretion of certain waste products, neutralization of chyme, aid in digestion and absorption fats.
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What two main components are excreted in bile?
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Cholesterol and bilirubin (from apoptosis of erythrocytes).
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What causes jaundice?
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Accumulation of bilirubin in skin, blood, etc due to excess production (via hemolytic anemia) or liver disease.
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How does bile aid in the neutralization of chyme?
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Bile epithelium adds bicarbonate to bile.
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How does bile aid in the digestion and absorption of fat?
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Bile salts synthesized from cholesterol acts like a soap to break up and emulsify.
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What is a naming convention for bile salts?
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Ends with -cholate.
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Where does deamination of amino acids take place?
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The liver
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Where is urea formed?
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The liver
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How is urea formed?
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Two NH2 molecules bind to a CO2 molecule in the liver.
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Where are most plasma proteins formed?
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The liver
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Where are non-essential amino acids formed?
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The liver
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