PNB 2265 INTEGRATED MEAL RESPONSE EXAM QUESTIONS ANSWERED CORRECTLY LATEST UPDATE 2026

PNB 2265 INTEGRATED MEAL RESPONSE EXAM QUESTIONS ANSWERED CORRECTLY LATEST UPDATE 2026 Phases - Answers -cephalic -gastric -intestinal -colonic Saliva - Answers -cephalic secretion mostly containing water and ions -prod. through chewing or activation of parasympathetic NS -secreted by exocrine glands (parotid, sublingual, submandibular) Saliva chemicals - Answers lysozyme- breaks down cell walls of bacteria fluoride- strengthens enamel HCO3- neutralizes acids in food we consume Saliva carb digestion - Answers begins saliva carbohydrate digestions bc it contains amylase and lipase Cephalic phase: swallowing - Answers -peristalsis in esophagus allows food to move from mouth to stomach -coordinated contraction and relaxation of smooth muscle that creates pressure gradients -involuntary process -upper esophageal sphincter (voluntary) -lower esophageal sphincter Upper esophageal sphincter - Answers -made of skeletal muscle (voluntary control) -relaxes to allow food to enter esophagus Lower esophageal sphincter - Answers -made of smooth muscle (involuntary) -opens to let food into the stomach Achalasia - Answers -caused by muscle contraction in lower esophagus which generates high pressure there, pressure becomes so high it is hard to move bolus into that region bc we can't generate enough pressure -feeling of food being stuck Pressure between esophagus and stomach - Answers -when the lower esophageal stomach pressure is higher than the pressure inside the stomach, the lower esophageal sphincter opens to allow food into the stomach -at all other times lower esophageal sphincter is closed to prevent stomach acid reflux back into the esophagus Gastroesophageal reflux disease (GERD) - Answers -failure of lower esophageal sphincter to close properly -results in stomach contents moving back up into esophagus when stomach pressure is higher -caused by changes in esophageal pressures Things that lower esophageal pressure - Answers -linked to GERD -caffeine, alcohol, cigarettes, chocolate Gastric phase - Answers events taking place inside of the stomach when food enters Stomach anatomical divisions - Answers -cardia, fundus, body (proximal) -antrum, pyloric sphincter (distal) Stomach functional divisions - Answers proximal - reservoir distal - pump/grinder Proximal stomach - Answers -allows stomach to expand to hold food -not a lot of peristaltic activity -closest to esophagus Distal stomach - Answers -closest to small intestine -a lot of motility peristalsis, mixing, grinding Stomach rugae - Answers -ridges on inside lining of stomach that increase stomach surface area -stretch as stomach increases in volume Stomach oblique layer - Answers -additional muscle layer in the muscularis externa -allows for stronger motility and peristalsis bc more muscle = more contraction Stomach protection - Answers -stomach prod. a lot of acid bc of parietal cells so has specializations to protect from tissue damage -mucous and bicarbonate are prod. in proximal and distal regions of the stomach that create a buffer to help protect esophagus and small intestine from tissue damage bc they do not have specializations Gastric pits - Answers -where secretions other than mucous come from -specialization of epithelial layer of gastric mucosa Parietal cells - Answers -secrete HCl (acid) and intrinsic factor (B12 absorption) Regulation of acid production - Answers -controlled through the activity of parietal cells -G cells, D cells, ECL cells G cells - Answers secrete the hormone gastrin D cells - Answers secrete the peptide messenger somatostatin ECL cells - Answers secrete histamine Chief cells - Answers -secrete the inactive enzyme pepsinogen -when pepsinogen interacts w HCl acid, it gets activated and becomes pepsin (an endopeptidase) H+/P+ ATPase proton pump - Answers -proton pump needed to get H+ into the lumen to form HCl -so acid prod. is regulated by this pump Regulation of acid through proton pump - Answers -all pumps have ATPase domains that require ATP hydrolysis in order to run -when ATP hydrolysis increases, acid prod. increases -when ATP hydrolysis decreases, acid prod. decreases Proton pump of parietal cell - Answers -regulated through phosphorylation by kinases -protein kinase A -protein kinase C -increasing activity of these kinases phosphorylates the proton pump and increases acid prod. Protein kinase A - Answers -cAMP dependent Protein kinase C - Answers -Ca+ dependent Histamine - Answers -secreted by ECL cells -has Gs coupled receptors on basal lateral mem. of parietal cells -when histamine binds, the production of cAMP is stimulated which activates protein kinase A -phosphorylation increases and acid prod. increases Gastrin - Answers -secreted by G cells -has Gq coupled receptors on basal lateral mem. of parietal cell -when gastrin binds, it triggers an increase in intracellular Ca+ which activates protein kinase C -phosphorylation increases and acid prod. increases Somatostatin - Answers -secreted by D cells -has Gi coupled receptors on basal lateral mem. of parietal cell -when somatostatin binds, adenyl cyclase is inhibited which stops cAMP prod. and protein kinase activation -decreases phosphorylation and decreases acid prod. Acetylcholine - Answers -has Gq coupled muscarinic receptors on the basal lateral mem. of parietal cell -when Ach binds, it triggers an increase in intracellular Ca+ which activates protein kinase C -phosphorylation increases and acid prod. increases Local activation of proton pump - Answers involves just the responses of the cells in the gastric mucosa to stomach contents in the lumen Gastrin direct stimulation - Answers -when food is sitting in stomach many proteins are waiting to be digested, the G cell turns on and releases gastrin into the bloodstream -gastrin finds receptors on the basal lateral mem. of parietal cell which increases intracellular Ca+ and allows protein digestion to start Gastrin indirect stimulation - Answers -gastrin also has receptors on ECL cells which produce histamine -when bound with gastrin, ECL cell is stimulated and go on to stimulate parietal cells Negative feedback - Answers -an acid is a high conc. of H+ ions so the more proteins you build up, the more acidic stomach gets -the buildup of H+ ions activates the D cells -D cell decreases cAMP prod. which turns off protein kinase A prod. which turns down the proton pump to stop acid prod. -neg. feedback loop ensures that when food stimulus goes away, acid. prod turns off Direct vagal stimulation - Answers -when hungry, thinking about food or smelling food, higher brain centers are activated -releasing Ach onto cells turns them on -innervated by parasympathetic NS Receptive relaxation - Answers -food in esophagus -tissues in esophagus are innervated by neurons that have stretch receptors which send afferent info to NS -NS sends signal back which inhibits the smooth muscle in the stomach causing relaxation -prepares stomach for the food about to enter Adaptive relaxation - Answers -stretch receptors in the stomach create same response to create more stretching Pyloric sphincter - mixing - Answers -separates the stomach and small intestine and is usually closed -when stomach creates forceful peristaltic contractions, the gastric juices crash against the closed pyloric sphincter -this creates a churning that helps mix together secretions w the digestive enzymes and breaks up food into smaller pieces before sending it to the small intestine Active stomach - Answers if stomach is very active it favors mvmt of things out of the stomach Active small intestine - Answers if small intestine is very active it inhibits mvmt out of the stomach Distention - Answers -stomach stretches out to a point and when that point is reached, further stretching will empty the stomach bc it can only accommodate so much Digestive products in gastric motility - Answers -food in stomach results in secretions like gastrin which stimulates gastric emptying into small intestine -gastrin increases contraction in the stomach Absorption in the stomach - Answers -stomach wall is not specialized for absorption (small surface area, no villi, no brush border) -can absorb aspirin and alcohol quickly Stomach wall protection - Answers -protected by a later of mucous that covers the mucosa of the stomach -alkaline mucus creates a barrier against acidic HCl -mucosal cells are rapidly replaced via mitosis Chemotherapy effect on stomach wall - Answers -chemotherapy drugs target rapidly dividing cells -tissue damage occurs by HCl when the drugs inhibit the mucosal cells' rapid division -can cause bad GI side effects Intestinal phase - Answers process of sending food from stomach to the duodenum (proximal part of the small intestine closest to the stomach) Gastric emptying - Answers to empty stomach, must contract smooth muscle in the stomach, and inhibit contraction of the pyloric sphincter so it relaxes Histamine in gastric emptying - Answers -histamine causes smooth muscle contraction -histamine release would cause stomach to contract and pyloric sphincter to contract which would close the door and nothing could leave the stomach -histamine release is too broad Neural control on pyloric sphincter - Answers -when stomach needs to be emptied, the NT vasoactive intestinal peptide (VIP) is released -causes pyloric sphincter to relax -at the same time, Ach, histamine, and gastrin promote the contraction and emptying in the smooth muscle in the stomach Enterogastrones - Answers -small intestine secretions that inhibit gastric emptying (the stomach) -secretin, CCK, gastric inhibitory peptide GIP Secretin - Answers -released due to low pH in duodenum (low pH comes from stomach acid) -when stomach empties meal into duodenum, secretin is released -inhibits the release of more acidic juice -brings bicarbonate into small intestine to neutralize stomach acid CCK - Answers -released due to fatty components of meal -important for starting fat digestion in small intestine Gastric inhibitory peptide (GIP) - Answers -released due to carb components in meal -triggers insulin release which helps body to use some of those sugars once they get absorbed into the bloodstream