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110 Cards in this Set
- Front
- Back
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Does chewing alter rate of digestion and absorbtion?
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No. Chewing basically just prevents choking
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Describe chewing
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It it voluntary and a reflex
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What stimulates salivary secretion?
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Both SNS and PNS, no hormaona lregulation
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Cephalic phase of saliva production
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induced by smell or sight of food. The reflex can be conditioned to other cues (Pavlov)
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What initiated salivary reflex?
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Chemorectors and pressure recptors in the mouth and on the tongue
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What cause watery saliva?
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stimulation of alpha one receptors
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What does increased blood flow to the salivary glands cause?
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increased saliva via the PNS
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Sjorgren's syndrome
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immune disorder. nonfunctioning exocrine glands including salivary glands. Patient must frequently sip water and oral fluoride treatments are prescribed
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swallowing mechanism
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elevate soft palate
epiglottis moves down upper esophageal sphincter open so food can pass through |
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skeletal muscle
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upper esophagus is skeletal muscle, middle esophagus is both skeletal and smooth m, the lower esophagus is smooth m.
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Describe food moving through upper esophagus
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relax the skeletal upper esophagus. Wave of contraction using peristaltic primary and secondary waves to move the bolus down
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Describe food moving through lower esophagus
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this is a reflex that occurs when bolus reaches the lower esophagus.
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Where is the swallowing center?
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in the brainstem, the medulla oblongata
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Barrier between the stomach and the esophagus
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Diaphragm
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How does pregnancy cause a hernia?
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because the lower esophagus is pushed into the diaphragm
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Heartburn
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irritaion of the esophagus from HCL from the tummy. Causes erosion of the lower esophagus
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parts of the stomach
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fundus, body, and antrum
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What does the body of the stomach secrete?
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mucus, pepsinogen, and HCl
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What does the antrum of the stomach secrete?
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secretes mucus and pepsinogen
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What cells secrete pepsinogen?
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Cheif cells
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What cells make HCl and intrinsic factor?
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parietal cells
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flow of bile from liver to SI
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Caliculi-bile duct-common
hepatic duct-common bile duct-sphincter of Oddi- duodenum (SI) |
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ducts in liver where bile is
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bile is secreted by liver cells into ducts called bile canaliculi
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What is needed for fat absorbion and digestion?
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Bile salts
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Main phospholipid for fat absorbtion
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Lecithin
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What is secreted along with bile by the liver?
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Bicarbonate and other salts, cholesterol, billirubin, trace metal
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What is bile salts made of?
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Cholesterol
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bilirubin
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bile pigment. it is the breakdown of RBCs. It is yello. billirubin is eliminated by the kidneys so pee is yellow, it also causes poo to be brown because it turns brown in the LI
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What happens if bile pigmens are retained in the circulation and is not secreated in the proper amount
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Jaundice
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what happens hormonally if there are a hi number of fatty acids and amino acids in the duodenum?
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the duodenum causes an increse in CCK, increase in plasma CCK, causes gall bladder to contract and the sphincter of oddi to relax. It also increases the bile flow into the common bile dut so it increase the bile flow to the duodenum
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Enterohepatic circulation of bile salts
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bile salts are in duodenum. go to illeum and secondary transport system of bile salts recycle them by a Na+ electronchem gradient. Bile salts travel back to the liver by the hepatic portal vein to by resynthesized in the bile.
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Amount of bile salts that is pooped out
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5%
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when is bile salts stored in the gall bladder?
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if person is fasting bile salts are stored in the Gall bladder
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When does bile salt go straight to SI?
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When eating, bile salts are circulated through the enterohepatic sysem while we eat
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What does CCK inhibit?
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gastric secretion and motility
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What does CCK cause secretion of?
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HCO3 secretion by pancrease and liver and causes the relearse of pancreatic enzymes.
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What does SI secrete?
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Mucus for lubrication and Chloride, sodium, and bicarbonated ions to allow secretion
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How does ions in SI aid with secretion?
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Cotransport with Cation.
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Main avenue of secretion in SI
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Chloride channel
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How is chyme in SI?
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hypertonic
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Describe absorbtion in SI
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LArge net absorbtion due mainlty due to the transport of sodium with water following by osmosis
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Primary function of segmentation motility in SI
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mixing with secretions, enzymes from liver and pancrease. It allows bolus to enter apical surface of SI
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Describe segmentaion motility in SI
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slow waves to break food down and make molecules smaller. It allows mixing of chyme
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number of segmentation contractions per minute in the duodenum
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12 per min. hi frequency in duodenum
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number of segmentation contractions per minute in the ileum
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9 contractions per minute.
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What causes movement from the pyloric valve to the illeocecal sphincter?
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segmentation motililty or slow waves
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What is frequency of slow waves different in duodenum and illeum?
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becuase the tissue pacemake potential differs so changes amount of action potentials
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What initiates myoelectric complex?
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motilin initiated
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When is motilin increase in the SI?
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after a meal is absorbed. it starts in the tummy and moves a few feet squeezing the volume down from the duodenum to the illeum. the series in continuous until the next meal. It sweeps bacteria out of the SI
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Gastroileal reflex
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segmentaion intensity in the ileum increase during periods of gastric emptying causing the food to move to the LI
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What causes the gastroileal reflex?
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food going through the pyloric sphincter
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Intestino intestinal reflex
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cessation of intestinal motility due to large distentions of the small intestine. motility just stops
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What causes intestino intestinal reflex?
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large distension of intestine, injury to intestinal wall, and various bacterial infections
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Function of Li
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store and concentrate fecal material before defication
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anatomy of LI
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illeocecal valve-cecum with appendix-transverse colon- descending colon, sigmoid colon-rectum-anus
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What does Li secret?
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mucus and fluids containing potassium and bicarbonate
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haustra
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bumps of LI that is circular muscle
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What happens as haustra moves?
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semental contractions occur
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where does gastroileal reflex occur?
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at the illeocecal sphincter
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what does LI absorb?
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not much but alittle absorbtion of sodium and ater
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Flatus
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intestinal gas in LI
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What composes flatus?
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nitogen, carbon dioxide, hydrogen, methatne, and hydrogen sulfide
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velocity of segmentation motility in LI
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2 per hour this is the contraction of the circular muscle or haustra
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Two types of movements in the LI
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segmentation contraction and mass movesments
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mass movements in LI
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follows meal it is a wave of intense contractions in the transverse colon. Due to gastroilleal reflex it clears all of the contents in thetransverse colon
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internal anal sphincter
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smooth muscle
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External anal sphincter
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skeletal movement so has voluntary control
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Defecation reflex
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distention in rectum bc mechanoreceptors causing the urge to poop.
Contract the recturm. relax the internal anal sph. contract external anal sph. increase peristaltic activy in sigmoid conlon. valsalva maneuer |
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valsalva maneuver
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deep breath, close glottis, contract ab and thoracic muscles
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ulcer
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erosion of the gastric, esophageal or duodenal surface
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what is natural protection against ulcers?
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alkaline mucus to provide viscosity for acid, tight junctions to prevent flow of fluid, and rapid epithelial replacement
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Endoscope
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through mouth to look for ulcers in esophagus and stomach
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Bacteria that causes ulcers
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Heliobacter pylori
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Two types of acid inhibitors
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1. histamine blockers
2. block H+/K+ ATPase pump |
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Histamine blockers
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Cimetindine, Tagamet, and Rantidine, Zantac. Block histamine receptors
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Type of medications that inhibit the hydrogen-potassium ATPase pump in parietal cells
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Omerprozole
Prilosec Lansoprazole Prevacid Esomerprazole Nexium |
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Vomiting
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Forceful expulsion of contents of stomach and upper intestinal tract through the mouth
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Vomiting center
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in medulla oblongata
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Effects of severe vomitting
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dehydration and circulatory problems and metabolic alkalosis
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how does severe vomitting cause metabolic alkalosis?
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H+ is secreted into the lumen and HCO3 goes into blood via countertransport therefore when you loose material through vomitting it causes an increase in flow of acid production to the lumen to replace the lost H+ so also increase the amount of HCO3 out of basolateral membrance into the blood, increasing alkosis
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Gallstones
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crystallized cholesteror or precipitated bile pigments
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2 places gallstones can lodge
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1. lodge in gallbladder
2. lodge in common bile duct |
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what happens if gallstone lodges in gallbladder?
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disrupts the bile flow from the Gall bladder into the SI
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What happens if gallstone lodges in teh common bile duct?
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At sphincter of Oddi it prevents bile entery of pancreatic enzymes and Gall bladder secretions to the SI
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Steatrrhea
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gall stone in common bile duct so cant absorb or digest fats. you get fats infecal material. causes diahrea, increase in fa, and increae in tonicity
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Jaundice
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Gall stone in the bile duct so bile pigments cant be secreted by liver, therfore, you look yellow
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Cholecystectomy
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remove Gallbladder if gall stone cannot be broken down
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lactose intolerance
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inability to digest lactose to glucose and galactose because of a decline in the enzyme lactase in the luminal plasma membranes of the small intestine
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Can infants break down lactase?
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yes always
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What happens if adults lose ability to digest lactase?
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diahrea bc hypertonic condition in lumen so water comes in with it
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constipation
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infrequent bowel movements
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What does constipation cause?
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toxic fecal material bc when hold poo too long too much water gets absorbed and it hurts to poo
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What increase frequency or ease of bowel movements?
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Laxatives. Use Magnesium and salts to bring H2O into colon to follow tehe salts. Also fiber can be used because it is not digested it just increases water absorbtion
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Diarrhea
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large frequent watery stools resulting from decreased absorbtion and increased secreation
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Cholera
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very severe diahrea due to bacteria causing an increase in secretions
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Traveler's diarrhea
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works on Chloide channels so increasing Cl causes water reabsorbtion too. also causes increase in secretions. Due to bacteria
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Effects of severe diahrrea
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1. Dehydration and circulatory problems bc secretions from ECF
2. potassium depletion and metabollic acidosis. lose K and HCO3 is secreted into the lumen side so push acid into the blood at the basolateral side |
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Where is chyme produced?
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Stomach
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Where does most digestion occur?
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SI
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Initial secretion of SI
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duodenum
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Sphincter between stomach and SI
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pyloric
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Where are enzymes made?
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pancrese, stomach, SI
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What do parietal cells release?
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HCL and intrinsic factor.
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only way the body can absorb vitamin B12
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intrinsic factor
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no B12
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pernicious anemia
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what causes release of enzymes in pancrease?
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CCK
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What causes release of HCO3 in pancreatic cells?
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secretin
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what do pancreatic cells secrete?
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enzymes and HCO3
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what causes acid production?
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Histamine
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What produces the driving prssure for the unidirectional movement of blood throughout the body?
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the pumping action of the heart.
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