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62 Cards in this Set
- Front
- Back
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What does the vagus innervate in Large intestine?
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Proximal Colon
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What does the pelvic nerves (s2-s4) innervate?
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distal colon rectum and anus
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what is the fxn of the stomach?
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Short term storage
Secreting intrinsic factor begin digesting proteins sterilize meal Slowly release food to the SI |
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What are the two type of glands in the stomach and where are the located?
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Gastric fundus and body
and Pyloric antrum |
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WHat does the Gastric gland secrete?
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HCl
Pepsinogen Intrinsic Factor Mucus Rennin(chymosin) |
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What does the Pyloric
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gastrin mucus and small amounts of pepsinogen
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what are the three cell types of gastric glands?
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Mucus neck cells-mucus
PEptic cells (chief cells)-pepsinogen and rennin Parietal cells-HCl and intrinsic factor |
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What does the gastric acid do?
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sterilize conversts pepsinogen to pepsing and protein digestion
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What does intrinsic factor do?
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binds b12 for absorption in the ilieum
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what do the neck cells do?
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secrete mucus to maintain stomach lining ph at 7 1 mm thick and respond to physical and chemical irritants and release intrinsic factor
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what percent of the stomach secretes hcl and how much
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proximal 80% and 1-2 L a day
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If there is no intrinsic factor or receptors how much b12 gets absorbed?
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1/50th
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What is b12 for?
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maturation of RBC
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what is pepsin?
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a protolytic enzyme needs low ph
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What causes pepsinogen release?
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vagal stimulation via acH and response to gastric acid
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What do the g cells secrete? what does it do?
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hormone that stimulates secretion of gastric acid (HCl) by the parietal cells of the stomach, as well as aiding in gastric motility. It is released by G cells in the stomach, duodenum, and the pancreas
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What stimulates gastrin release?
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Gastrin releasing peptide and small peptides and AA
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What inhibits gastrin release?
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Somatostatin and low pH
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What cause histamine release from enterochromaffin like cells? what does histamine do?
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Gastrin and AcH, causes histamine receptor on parietel cells to release H+ in stomach
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What causes HCl release in the cell?
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AcH via musccarinic receptro
Histamine- H2 receptrors -> cAMP GAstrin: gastrin cckb receptor --> Ca2+ |
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what are the three phases of gastric secretion?
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Cephalic-head seeing food release HCL and pepsinogen 20 %
Gastric phase-70% HCl, pepsin and gastrin occurs when food enters stomach Intestinal phase-gastrin 10% when food enters SI |
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What is the cephalic stage
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20% casued by hunger mechano and chemoreceptors and thinking about it if vagotomy no secretion at all
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during gastric phase what causes more acid secretion
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increased ph distention peptides and AA and calcium coffee wine all respond with gastrin release unless from nervous then direct HCl release
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what is the intestinal phase divided into
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early small secretion of gastric juices from response to chyme in duodenum
and late phase low ph <2 I cells release CCK and decrease gastrin and inhibit motility and s cells release secretin which inhibits patietal cell and gastrin release and somatostatin released also reduce gastrin release |
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What do brunners glands do?
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Release mucus to protect duodenum
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What do the crypt of lieberkuhn do? are these only in small Interstin or also large?
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all through SI serous release watery fluid like extracellular ph 6.5-7.5 and about 2L a day liquify chyme also located in both but LI no villia and secrete alkaline solution and mucus release caused by PS increase
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What is the role of the pancreas?
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Release bicarb and breakdown macromolecules via release of digestive enzymes
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What is in pancreatic secretion?
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Aqueous part-h2o Na and bicarb made by cells that line pancreatic duct
Enzymatic part-protolytic enzymes lipase and amylase |
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How are enzymatic secretions stored? what controls its secretion?
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zymogens and CCK activated when they reach intestine
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what does secretin CCK and nervous response do in the pancrease
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Secretin released by SI in response to H+ and fats cause increase fluid secretion and bicarb release
CCK in SI released in response to fats and AA cause increase release of enzymatic secretion Nerve increase enzymatic secretion |
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What are the phases of pancreatic secretion and what %
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Cephalic 20% vagus
Gastric 10% cagus Intestinal 70% mediated by acid>secretin>hco3 fat/protein>cck>enzymes acid/fat/protein> vagovagal Ach> enzymes |
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During the cephalic phase what happens when pancreas is stimulated but the vagal nerves
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Enzymatic and aqueous components released
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During the gastric phase of pancreas release what is released?
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mainly enzymatic components and a little aqueous solution in duct cells
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During Intestinal phase what is the major stimulus and what is released
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have little vagal mostly enteric nerves cause release of enzymes and hco3 also I cells respond to fat and protein release CCK which stimulates enzyme release and S cells release secreting in response to acid which releases aqueous component
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What reflex is initiates upon protein and fat breakdown which acts on acinar cells
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vagovagal
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what does CCK do in the duodenum?
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affect and results are:
Gallbladder->contraction Pancreas->acinar secretion Stomach->reduced emptying Sphincter of Odi->relaxsizyl |
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What does secretin act as?
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pH meter
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What is a peptic ulcer?
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Group of ulceritive disorders that occur in the upper GI caused from exposure to acid-pepsin results from when the body is unable to create enough mucus to protect from the damaging effect
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Duodenal ulcers? what causes them?
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caused from the increased exposure to acid and pepsin caused by a massive overgrowth of 2-3 x more parietal cells
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What causes ulcers?
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H. pylori
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what is the 2nd most common cause of ulcers?
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NSAID since they inhibit mucus
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WHat type of bacteria is h pylori? what do they cause?
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gram negative which has a high urease activity with high NH4 can withstand acid enviroment and increases acid secretion
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Treat for h pylori?
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antibiotics and H-K atpase inhibitor or antihistamine
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what is a proton pump inhibitor?
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Omeprazole
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what is an H2 receptor blocker
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Rantidine and Cimetidine
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WHat is Zollinger Ellison Syndrome
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Gastrin secreting tumor caused by neuroendocrine tumor (gastrinomas) tumors could be anywhere in GI like duodenal wall pancreas lymph nodes must remove tumors
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WHat is achalasia?
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food stuck in esophagus due to LES not relaxing and esophagus becomes enlarged which can cause rupture, ulcers and death. Caused by ENS problems
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What are the symptoms of achalasia and megaesophagus?
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Difficulty swallowing often regurgutate food and have weight loss, excessive belching and heartburn
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What is the treatment to Achalasia/ Megaesophagus?
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2 things antispasmodic drugs which can relax SM
or but balloon down throat and stretch LES |
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What occurs in GERD?
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backflow of food from stomach to eso caused by:
weak or incompetent LES Delayed gastric emptyingmay also contribute to reflux by increasing gastric volume and pressue very common can cause berettes eso |
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How can GERD be reduced?
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Avoid large meals and food with alcohol, caffeine and smoking elevate head antacids and use stronger medication like H2 blockers or proton pump inhibitors (omeprazole, lansoprazole etc...)
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WHat are some gastric motility problems?
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Slow gastric emptying so you have fullness loss of apetite could be caused by ulcer cancer and eating disorder treatment is ballon dilation
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What is gastroparesis?
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Slow emptying of the stomach/paralysis caused from type I diabetes (20%) which uncontrolled damages vagal nerve and causes weight loss , nausea comiting and feeling full.
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What is rapid gastric emptying?
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Symptoms diarrhia, hypotension, reactive hypoglycemia and duodenal ulcers caused by gastric operations and pyloroplasty
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WHat is encopresis?
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Frequent bowel movement accidents in male older than 4 1-3% of boys. chronic constipation cause loss of sensation in colon leading to accidents of normal feces with hard center like a tootsipop only reversed
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What are some causes and treatments for diarrhia?
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Caused by infectious organism like ecoli rotavirus salmonella chigella last two destro intestinal epithelial cells one way to treat is with oral replacement therapy ORT or compounds that inhibit gastric motility or antibiotics
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What substances increase SI motility? what decreases it?
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Increase- CCK Gastrin, Insulin, Motilin and serotonin
Decrease- Secretin and glucagon |
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What reflexes rely on the enteric system?
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Enterogastric, gastroenteric and myenteric reflex
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What is the most potent stimulator of pancreatic secretions?
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Secretin which causes lots of bicarb release in response to acid and also isotonic volumous fluid secretions
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what prevents the pancreatic enzymes from being activates?
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trypsin inhibitor
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how does gastrin cause hcl release?
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it stimulates enterochromaffin cells to release histamine which then causes parietal cell hcl secretion
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what secretes pepsin which cell type?
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chief cells in the stomach
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