Wages Digestive System
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113 terms
Terms | Definitions |
|---|---|
 What are the functions of the digestive system? | To obtain nutrients, water, vitamins and electrolytes needed for energy production, growth & repair. |
| What are the 2 divisions of the digestive system? | alimentary canal and accessory structures |
| What structures are in the alimentary canal? | mouth, pharynx, esophagus, stomach, small intestine, large intestine. |
| What structures are in the accessory structures? | teeth, tongue, gallbladder, salivary glands, liver, pancreas |
| What are the 6 digestive processes? | ingestion, propulsion, mechanical digestion, chemical digestion, absorption, defecation. |
| What is ingestion? | The only activity that is completely voluntary. Taking in food. |
| What is propulsion? | Begins with deglutition (swallowing) which initially is voluntary then peristalsis takes over. |
| What is mechanical digestion? | Physically breaking down the foodstuff. Chewing, stomach churning and segmentation in the small intestine. |
| What is chemical digestion? | Chemical bonds are broken using enzymes. |
| What is absorption? | Moving nutrients from the gut to the bloodstream (water soluble) or lymphatic system (fat soluble). |
| What is defecation? | The elimination of indigestible material as feces. |
| What are the 4 layers of the gut wall. Specifically in the small intestines. | Mucosa, submucosa, muscularis externa, serosa |
| What does the mucosa protect and function as? | The mucosa lines the gut and functions in secretion and absorption. |
| What are the 3 sublayers of the mucosa? | epithelium, lamina propria, muscularis mucosae |
| What is the epithelium of the mucosa consist of? | simple columnar epithelium with goblet cells (produce mucus) and enteroendocrine cells (produce hormones). |
| What is the lamina propria contain? | Made of loose c.t. containing the ends of nerves, capillaries, and lymphatic vessels. |
| What is the muscularis mucosae? | Thin layer of muscle. |
| What does the submucosa consist of and it's function? | Layer of dense c.t. containing blood vessels, lymph vessels, nerves, and epith glands. Has extensive vascular system to transport absorbed materials. |
| What does the muscularis exererna consist of and it's function? | Responsible for motility for peristalsis. Made of skeletal muscle at both ends of gut, smooth muscle in between. |
| What does the serosa consist of and it's function? | Layer of loos (areolar) c.t. covered by simple squamous epith. Forms part of the peritoneum, layer of tissue lining the ab cavity Above diaphragm the lining is fibrous c.t. - adventitia |
| What does the enteric nervous system regulate? | motility, secretions, and blood flow of the digestive system. |
| The enteric nervous system are composed of what 2 networks that are pare of the parasympathetic n.s.? | Submucosal nerve plexus. Myenteric nerve plexus. |
| What does the submucosal nerve plexus regulate? | It is sensory and motor. Regulates the glands & smooth muscles in the mucosa. |
| What does the myenteric nerve plexus control? | Controls peristalsis. |
| What does the lesser omentum cover? | Mesenteric tissue extending from the stomach up to liver. |
| What does the greater omentum cover? | Layer of fat. Hangs down from the stomach that covers the intestines. |
| What does the omenta contain? | Lymphatic vessels with a large number of lymph nodes and help prevent infection in the peritoneal cavity. |
| What are the names of the salivary glands? | Parotid, Submandibular, and sublingual. |
| What are the functions of the salivary glands? | Cleans the mouth Contains lysozyme - digestive Lubricates food Dissolves food Contains IgA - lines digestive tract Contains salivary amylast - b/d starch Contains lingual lipase - b/d lipids |
| How many deciduous teeth are there? | 20 teeth |
| How many permanent teeth are there? | 32 teeth |
| Enamel covers what part of the tooth? | crown |
| Which teeth are sharp and used for cutting, to bite off a piece of food? | Incisors |
| Which teeth are more pointed teeth to puncture and shred food? | Canines |
| Which teeth are flat, broad surface for grinding and chewing food? | Bicuspids and molars |
| What is another name for the throat? | pharynx |
| The tube that connects the pharynx to the stomach? | esophagus |
| What are the inner lining of the stomach that have creases called? | Rugae - stretch out as the stomach fills. |
| What are the 4 regions of the stomach? | Cardiac - esophagus goes into stomach Fundic - dome-shaped upper portion Body - bulk of stomach Pyloric - narrow pouch at the end |
| What is the stomach lined with? | simple columnar epith |
| The simple columnar epithelium in the stomach are made of what? | mucous cells that produce alkaline mucus |
| What are the 4 secretory cells of the gastric glands? | chief cells parietal cells mucous neck cells enteroendocrine cells |
| What is the most common secretory cell? | chief cell |
| What does the chief cell produce? | Pepsin Gastric lipase |
| What does the parietal cells produce/secrete? | Secrete HCl & intrinsic factory for B12 absorption. |
| What does the mucous neck cells produce? | Acidic mucus that lines the stomach in the neck region of the glands. |
| What does the enteroendocrine cells produce? | hormones that regulate digestion such as gastrin, serotonin, cholecystokinin |
| What are the 3 segments of the small intestines? | Duodenum, jejunum, ileum |
| Which segment of the small intestine comes directly off the stomach? | Duodenum - with ducts coming from liver & pancreas. |
| What segment is the middle part of the small intestines? | Jejunum |
| What segment is the lower part of the small intestines that attaches to large intestines? | Ileum |
| What are the adaptations of the small intestines to increase surface area? | Highly coiled Circular folds - plicae Villi - fingerlike projections Microvilli - projections off of the apical membrane (called brush border) |
| What are the major brush border enzymes? | maltase, sucrase, lactase - digest CHOs aminopeptidase & dipeptidase - digest proteins |
| Ileum enters from the side of the large intestines through which valve? | Ileocecal valve |
| What are the 3 major structures of the large intestine? | cecum-contains vermiform appendix colon-contains ascending, transverse, descending & sigmoid colon rectum-Muscular for defecation & last inch is vascular anal canal. |
| What is the largest gland in body? | liver - exocrine gland |
| What are the functional cells in liver? | hepatocytes |
| What are the functions of the liver? | Produce bile, makes & stores glycogen, makes NE amino acids, turns ammonia to urea, makes plasma proteins, builds up & breaks down triglycerides, phospholipids, and cholesterol, detoxifies poisons, stores fat soluble vitamins (A,E,K,D) and recycles hemoglobin |
| The right and left hepatic duct from what? | Common hepatic duct |
| Which duct comes off of the common hepatic duct going to the gallbladder? | cystic duct |
| Which duct is below the cystic duct and goes into the small intestines? | bile duct |
| What is the function of the bile? | Stores and concentrates bile from the liver Contains bile salts - emulsify fats |
| The pancreatic duct joins the bile duct forming what? | duodenal ampulla - empties into duodenum |
| What are the 2 main components in pancreatic juices? | NaHCO3 - buffers chyme & balances the gastric juices from the stomach. Digestive enzymes |
| What are the main digestive enzymes? | Trypsin Chymotrypsin Carboxypeptidase Amylase Lipase Ribonuclease Deoxyribonuclease All of these are secreted in inactive form and contain -gen at the end of the word. |
| What hormones stimulate secretion? | Secretin, Cholecystokinin, Gastrin |
| What is secretin? | From enteroendocrine cells of duodenum Release stimulated by acid in the duodenum. Stimulates pancrease to release bicarbonate-rich pancreatic juice Stimulate liver to release bile salts. |
| What is cholecystokinin? | Stimulated by protein and fat ingestion from duodenum. Stimulates release of enzyme-rich pancreatic juice Stimulates contraction of gallbladder forcing out bile |
| What is gastrin? | From the G cells in pyloric glands Stimulates release of HCl & intrinsic factor from parietal cells. |
| What are enzymes? | Proteins that catalyze reaction to speed up digestion. |
| What are digestive enzymes? | Hydrolases that break down substances by adding water. |
| Enzymes are specific to what? | Reactions they catalyze due to binding to a specific substrate forming an enzyme-substrate complex |
| What is diffusion? | Requires no energy; always from high to low concentration. |
| What is osmosis? | Diffusion of whater from high to low concentration. |
| What is simple diffusion? | no carrier, from high to low concentration |
| What is facilitated diffusion? | needs a carrier, from high to low concentration. |
| What is active transport? | Energy and carrier required from low to high concentration. |
| What is the general formula for CHOs? | 1C: 2H: 1O |
| Examples of polysaccharides. | starch glycogen |
| Examples of disaccharides. | Sucrose maltose lactose |
| Examples of monosaccharides | glucose fructose galactose |
| What is the job of salivary amylase? | Breaks down starch down to short glucose chains |
| What is the job of pancreatic amylase? | Quickly breaks the short glucose chains to the disaccharide maltose. |
| What is the job of maltase? | Brush border enzyme that hydrolyzes maltose to 2 glucoses. |
| What are the 2 brush border enzymes that breakdown sucrose and lactose to monosaccharides? | sucrase lactase |
| Sucrose can be broken down into what? | glucose and fructose |
| Lactose can be broken down into what? | glucose and galactose |
| How is fructose absorbed? | facilitated diffusion |
| How are glucose and galactose absorbed? | They are cotransported with sodium across the apical membrane. Facilitated diffusion is used to get them across the basal membrane. |
| How is glucose moved across the apical membrane? | Solvent drag - dissolved in water |
| What breaks down proteins to amino acids? | Proteases |
| How do proteases break down proteins? | Breaking the peptide bonds between amino acides. |
| What shortens the amino chains | Trypsin and chymotrypsin |
| What does HCl do to protein in the stomach? | Breaks down the c.t. around the muscle to allow enzyme access. |
| Protein digestion begins where? | In the stomach with the enzyme pepsin. |
| How is protein digestion finished | Using 3 brush border enzymes: Carboxypeptidase, Aminopeptidase, Dipeptidase |
| What does Carboxypeptidase remove? | Amino acids from the carboxy end (-COOH) |
| What does the Aminopeptidase remove? | Amino acids from the amino end (-NH2) |
| What does the Dipeptidase break apart? | Dipeptides |
| How are amino acids absorbed? | Being cotransported with Na+ using active transport across the apical membrane Then facilitated diffusion across the basal membrane and enters the blood. |
| Fats are broken down into what? | Monoglyceride 2 fatty acids by lipases |
| Most digestion of fat occurs where? | In the small intestines by pancreatic lipase. |
| What are bile salts and lecithin needed for? | emulsifying agents for lipid digestion and absorption. |
| Bile Salts and lecithin break up what? | Break up fat globules into fatty droplets and this increases surface area allowing lipase to do job quickly. |
| What does the lipase do? | Removes 1st & 3rd fatty acid producing 2 free fatty acids and a monoglyceride. |
| What are the 2 F.A.s and monoglycerides coated with? | Coated with bile salts forming micelles which include cholesterol and fat-soluble vitamines (A,E,D,K) |
| What do the micelles do? | Difuse to gut wall and release their lipids which diffuse across epith cells of villi. Bile salts are then recycled in gut. |
| Inside the cell, the Free FA and monoglycerides enter what? What happens to them there? | They enter smooth ER where they are put back together as triglyceride. |
| What does the Golgi do with the triglyceride? | Coated with phospholipids and proteins to form chylomicrons. Packaged into secretory vesicles, migrate to basal membrane. release their contents, enter lacteals. |
| DNA is broken down into what? | Deoxyribonuclease breaks down DNA into: Deoxyribose + Bases + Phosphate |
| RNA is broken down into what? | Ribonuclease breaks down RNA into: Ribose + Bases + Phosphate |
| What is the function of the large intestines? | Absorbe right amount of water, absorb sodium and chloride ions, defecation. |
| Why is the bacterial in large intestines important? | Makes up normal microbial flora and release Vitamin K & some B Vitamins and absorbed by human host. |
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