D313 Anatomy and Physiology II - Set 2 - Part 2

Correct Answer: Cephalic phase

Option c is correct because the cephalic phase is triggered by the thought, sight, or smell of food. The cerebral cortex and hypothalamus send signals via the vagus nerve to begin gastric secretions. Option a is incorrect because the gastric phase begins only when food physically enters the stomach and causes distension. Stretch receptors and G-cells then drive continued acid and enzyme production in response to actual food. Option b is incorrect because the intestinal phase is triggered when chyme enters the small intestine. It modulates stomach activity based on chyme composition in the duodenum, not on brain sensory stimuli. Option d is incorrect because the pyloric phase is not one of the three recognized phases of gastric regulation. The only three established phases are the cephalic, gastric, and intestinal phases named for stimulus locations.

Correct Answer: Cranial nerve X, the vagus nerve

Option b is correct because the vagus nerve, cranial nerve ten, is the primary nerve transmitting signals from the brain to the stomach. It regulates gastric secretions and digestive activity during the cephalic phase. Option a is incorrect because the facial nerve, cranial nerve seven, primarily controls facial expressions and transmits taste sensations from the anterior tongue. It has no significant role in regulating gastric secretory activity. Option c is incorrect because the hypoglossal nerve, cranial nerve twelve, controls tongue movements during speech and swallowing. It does not transmit signals to the stomach for regulating gastric secretions or digestive motility. Option d is incorrect because the glossopharyngeal nerve, cranial nerve nine, handles taste from the posterior tongue and some swallowing reflexes. It does not serve as the primary nerve controlling gastric function.

Correct Answer: Gastrin

Option d is correct because during the gastric phase, G-cells in the stomach lining release gastrin when food enters and distends the stomach wall. Gastrin stimulates continued hydrochloric acid and digestive enzyme production. Option a is incorrect because secretin is released by duodenal cells when acidic chyme arrives in the small intestine. It stimulates pancreatic bicarbonate release and belongs to the intestinal phase, not the gastric phase. Option b is incorrect because cholecystokinin is released by duodenal cells responding to fatty and protein-rich chyme in the small intestine. It stimulates gallbladder contraction and pancreatic enzyme secretion, not gastric acid production. Option c is incorrect because pepsinogen is not a hormone but an inactive enzyme precursor secreted by chief cells. It must be converted to active pepsin by hydrochloric acid before it can digest proteins.

Correct Answer: CCK and secretin

Option a is correct because CCK and secretin are released by duodenal cells when fatty or acidic chyme enters the small intestine. Together they signal the stomach to slow emptying and protect the duodenum. Option b is incorrect because gastrin actually stimulates gastric activity and motility rather than slowing emptying down. Pepsin is a digestive enzyme rather than a hormone and cannot send regulatory signals back to the stomach. Option c is incorrect because insulin and glucagon are pancreatic endocrine hormones that regulate blood glucose levels during absorptive and postabsorptive states. They do not play a role in controlling the rate of gastric emptying. Option d is incorrect because although serotonin and histamine participate in some gastrointestinal functions, they are not the primary hormonal pair responsible for the intestinal phase feedback that slows gastric emptying down.

Correct Answer: Parasympathetic nervous system

Option c is correct because the parasympathetic nervous system generally stimulates digestive activity, including increasing gastric secretions, promoting emptying, and enhancing motility throughout the alimentary canal during rest and digestion. Option a is incorrect because the somatic nervous system controls voluntary skeletal muscle movements like chewing and the initial swallowing phase. It does not regulate the involuntary digestive processes described in this question. Option b is incorrect because the sympathetic nervous system generally inhibits digestive activity during periods of stress or physical exertion. It diverts blood away from digestive organs and slows motility, producing the opposite effect. Option d is incorrect because the central nervous system refers broadly to the brain and spinal cord together. While it processes digestive signals, it is not an autonomic division that directly stimulates digestion.

Correct Answer: Cecum

Option a is correct because the cecum is the first segment of the large intestine that receives material from the small intestine through the ileocecal valve. The vermiform appendix opens directly into this structure. Option b is incorrect because the ascending colon follows the cecum and carries material upward along the right side of the abdomen. Material must enter the cecum first before passing into the ascending colon. Option c is incorrect because the sigmoid colon is one of the final colonic segments located between the descending colon and the rectum. It is far too distal to receive material entering the large intestine. Option d is incorrect because the rectum is the storage chamber near the end of the large intestine that holds feces prior to defecation. Material must pass through the entire colon to reach it.

Correct Answer: Cecum

Option d is correct because the vermiform appendix opens into and is physically attached to the cecum. The cecum is the first large intestine segment located just beyond the ileocecal valve from the ileum. Option a is incorrect because the ascending colon follows the cecum and carries material upward on the right side of the abdomen. The appendix does not connect to the ascending colon at any anatomical point. Option b is incorrect because the transverse colon crosses the abdomen horizontally between the ascending and descending segments. It is well beyond the cecum where the appendix is actually attached and opens. Option c is incorrect because the sigmoid colon is near the end of the colonic pathway just before the rectum. It is far too distal to have any direct connection with the vermiform appendix structure.

Correct Answer: Internal involuntary and external voluntary

Option b is correct because the internal anal sphincter operates involuntarily using smooth muscle, while the external anal sphincter is under voluntary skeletal muscle control. Together they regulate the timing of defecation. Option a is incorrect because only the external anal sphincter is voluntary and made of skeletal muscle. The internal sphincter functions automatically using smooth muscle without any conscious control from the individual whatsoever. Option c is incorrect because only the internal anal sphincter is involuntary smooth muscle. The external sphincter is voluntarily controlled, which is what allows a person to consciously choose the timing of defecation. Option d is incorrect because this reverses the control types of both sphincters. The internal sphincter is involuntary and the external is voluntary, which is the exact opposite of the arrangement described here.

Correct Answer: Water and salts

Option c is correct because the main action of the large intestine mucosa is absorbing water and salts from food residue. This converts liquid material into increasingly solid feces moving through the colon. Option a is incorrect because amino acids and simple sugars are absorbed primarily in the small intestine, especially the jejunum. The large intestine does not perform significant absorption of these nutrient monomers from residue. Option b is incorrect because fat-soluble vitamins and lipids are absorbed in the small intestine, with lipids entering lacteals of the villi. The large intestine does not significantly absorb these substances from food. Option d is incorrect because glucose and fatty acids are products of chemical digestion absorbed across the small intestinal wall. By the time material reaches the large intestine, these nutrients have already been absorbed.

Correct Answer: Approximately every two to three hours

Option a is correct because mass movements are large wave-like contractions in the large intestine that push contents toward the rectum for defecation. They occur approximately every two to three hours throughout the day. Option b is incorrect because mass movements do not occur continuously. They happen at periodic intervals, unlike the more frequent haustral contractions that mix contents locally for water absorption between mass movement events. Option c is incorrect because mass movements are not limited to once daily. They occur several times throughout the day at two to three hour intervals, progressively moving fecal material toward the rectum for defecation. Option d is incorrect because mass movements are infrequent powerful contractions, not rapid rhythmic events. Comparing their frequency to peristalsis greatly overstates how often these large propulsive waves actually occur in the colon.

Correct Answer: Bile emulsifies fat into smaller droplets

Option d is correct because bile does not contain digestive enzymes. Instead it breaks large fat globules into smaller droplets through emulsification, increasing the surface area available for pancreatic lipase to chemically digest. Option a is incorrect because bile does not chemically split fat molecules into fatty acids and glycerol. That chemical breakdown is performed by pancreatic lipase after bile has emulsified fat into smaller accessible droplets. Option b is incorrect because bile does not absorb fat directly into blood vessels. Fat absorption occurs through intestinal villi and lacteals after lipase has digested emulsified fat into absorbable monomer components. Option c is incorrect because bile cannot convert fat into glucose. Fat and glucose are different macronutrient classes with distinct chemical structures, and bile only physically disperses fat without altering its chemical identity.

Correct Answer: Under the right lobe of liver

Option c is correct because the gallbladder is a small green sac tucked under the inferior surface of the right lobe of the liver. It stores and concentrates bile continuously produced by the liver. Option a is incorrect because the gallbladder does not sit above the left lobe. It is positioned on the inferior surface under the right lobe, which is the larger lobe visible from the front. Option b is incorrect because the gallbladder is not behind the liver near the spine. It is attached to the undersurface of the right lobe in the anterior abdominal cavity, accessible during surgery. Option d is incorrect because the gallbladder does not sit beside the liver near the left kidney. It is tucked beneath the right hepatic lobe, not positioned laterally near any kidney on either side.

Correct Answer: Cystic duct and common hepatic duct

Option a is correct because the cystic duct from the gallbladder joins the common hepatic duct from the liver to form the common bile duct, which delivers bile to the duodenum for fat emulsification. Option b is incorrect because the pancreatic duct carries enzymes and bicarbonate from the pancreas. It does not merge with the cystic duct to form the common bile duct within the biliary ductal system pathway. Option c is incorrect because the common hepatic duct merges with the cystic duct, not the pancreatic duct. The pancreatic duct has its own pathway and does not form part of the common bile duct. Option d is incorrect because the left and right hepatic ducts merge within the liver to form the common hepatic duct itself. They do not directly form the common bile duct without the cystic duct.

Correct Answer: Liver and gallbladder secretions only

Option b is correct because the bile duct contains secretions from the liver and gallbladder only. Pancreatic juice travels through its own separate pancreatic duct to reach the duodenum independently of bile. Option a is incorrect because pancreatic secretions do not travel through the bile duct. The pancreas has its own dedicated duct that delivers enzymes and bicarbonate to the duodenum through a separate ductal pathway entirely. Option c is incorrect because the bile duct carries bile that was originally produced by the liver, not the pancreas. The gallbladder stores and concentrates this liver-produced bile but does not receive pancreatic contributions. Option d is incorrect because although liver secretions travel through the bile duct, pancreatic secretions use a completely separate duct system. The bile duct does not carry any pancreatic juice alongside bile.

Correct Answer: Liver

Option d is correct because the liver breaks down toxins so they can be excreted by the kidneys. This detoxification role is one of many critical non-digestive functions the liver performs alongside bile production. Option a is incorrect because the small intestine is primarily responsible for chemical digestion and nutrient absorption from food. It does not serve as a detoxification organ processing toxins for removal from the body. Option b is incorrect because the gallbladder only stores and concentrates bile produced by the liver. It has no role in detoxification or chemical processing of toxic substances circulating in the bloodstream. Option c is incorrect because the pancreas produces digestive enzymes and hormones such as insulin and glucagon. It does not detoxify substances or process toxins for excretion through the kidneys or other routes.

Correct Answer: Islets of Langerhans

Option c is correct because the islets of Langerhans are endocrine cell clusters within the pancreas that secrete hormones like insulin and glucagon directly into the bloodstream without using any ductal system. Option a is incorrect because crypts of Lieberkuhn are glands at the base of intestinal villi in the small intestine. They secrete lysozyme and are not endocrine hormone-producing structures found within the pancreas. Option b is incorrect because Brunner glands are found in the duodenum and secrete alkaline mucus to neutralize acidic chyme from the stomach. They are intestinal glands and are not located in the pancreas. Option d is incorrect because gastric glands are embedded in the stomach mucosa and contain specialized cells like parietal cells and chief cells. They are stomach structures and not found within the pancreas.

Correct Answer: Beta cells

Option a is correct because beta cells in the pancreatic islets are endocrine glands that secrete insulin directly into the bloodstream. Insulin lowers blood sugar by moving glucose from blood into cells after meals. Option b is incorrect because alpha cells produce glucagon, which raises blood sugar by mobilizing stored glucose into the bloodstream during fasting. They do not produce the hormone that lowers blood sugar levels. Option c is incorrect because chief cells are in the gastric glands of the stomach and secrete pepsinogen for protein digestion. They are not pancreatic cells and release no hormones into the bloodstream. Option d is incorrect because G-cells are found in the stomach lining and secrete gastrin to stimulate acid production. They are not pancreatic islet cells and do not affect blood sugar regulation in any way.

Correct Answer: Type one diabetes

Option d is correct because chronic pancreatic inflammation can destroy beta cells that produce insulin. Without sufficient insulin, the body cannot regulate blood glucose properly, leading to the development of Type one diabetes. Option a is incorrect because gastric ulcers develop from damage to the stomach lining caused by excessive acid or bacterial infection. They are not caused by pancreatic inflammation or destruction of islet beta cells. Option b is incorrect because gallstones form from crystallized bile components inside the gallbladder due to bile composition imbalances. They are not a metabolic consequence of pancreatic inflammation destroying endocrine cells. Option c is incorrect because chronic diarrhea results from rapid intestinal transit or impaired water absorption in the large intestine. It is not the primary metabolic disease caused by destruction of insulin-producing beta cells.

Correct Answer: Centroacinar cells

Option b is correct because centroacinar cells within the pancreas secrete bicarbonate ions into pancreatic juice. This bicarbonate buffers acidic chyme entering the duodenum from the stomach and protects the intestinal wall. Option a is incorrect because alpha cells are endocrine cells in the pancreatic islets that secrete glucagon into the bloodstream for glucose regulation. They do not produce bicarbonate for neutralizing acid in the duodenum. Option c is incorrect because beta cells are endocrine islet cells that produce insulin for blood glucose regulation. They secrete hormones into the blood and do not produce bicarbonate solutions for the pancreatic duct. Option d is incorrect because chief cells are found in stomach gastric glands and secrete pepsinogen for protein digestion. They are not pancreatic cells and have no role in producing bicarbonate for the duodenum.

Correct Answer: Glucagon during the postabsorptive state

Option c is correct because glucagon is secreted by alpha cells during the postabsorptive fasting state. It mobilizes glucose from storage sites into the bloodstream to maintain adequate blood sugar levels between meals. Option a is incorrect because insulin is active during the absorptive state and lowers blood sugar by storing glucose. The question asks about the hormone that mobilizes glucose during fasting, which is the opposite function. Option b is incorrect because gastrin is a digestive hormone stimulating gastric acid production in the stomach during food processing. It has no role in mobilizing stored glucose during fasting periods between meals at all. Option d is incorrect because secretin is a digestive hormone released by duodenal cells that triggers pancreatic bicarbonate secretion for acid neutralization. It does not regulate blood glucose during fasting metabolic states.