D313 Anatomy and Physiology II - Set 2 - Part 1

Correct Answer: Peristalsis

Option d is correct because the large intestine is the primary organ responsible for absorbing water from food residue. When material transits this organ too rapidly, inadequate water recovery causes diarrhea. Option a is incorrect because the small intestine primarily absorbs nutrients such as carbohydrates, proteins, and lipids from digested food. It is not the main organ responsible for recovering water from residue. Option b is incorrect because the stomach primarily performs mechanical churning and chemical protein digestion using pepsin and hydrochloric acid. It does not serve as the main site for water absorption from residue. Option c is incorrect because the cecum is only the first receiving chamber of the large intestine where material arrives from the ileum through the ileocecal valve. It does not perform most water absorption.

Correct Answer: Ileocecal valve

Option a is correct because the ileocecal valve guards the junction between the ileum and the cecum. It controls passage of material into the large intestine and prevents backflow into the small intestine. Option b is incorrect because the pyloric sphincter is located at the junction between the stomach and the duodenum. It regulates chyme release into the small intestine, which is a completely different anatomical location. Option c is incorrect because the lower esophageal sphincter controls food passage from the esophagus into the stomach. This structure is in the upper digestive tract, far from the junction with the large intestine. Option d is incorrect because the internal anal sphincter is located at the terminal end of the large intestine near the anus. It controls involuntary fecal release during defecation, not material entry into the cecum.

Correct Answer: Haustral contractions and mass movements

Option c is correct because haustral contractions are short localized movements that mix fecal contents to promote water absorption, while mass movements are larger wave contractions that push material toward the rectum for elimination. Option a is incorrect because peristalsis and segmentation are general motility terms describing movement throughout the entire alimentary canal. They are not the two specific motility types that are unique to the large intestine. Option b is incorrect because segmentation is a motility pattern primarily associated with the small intestine that mixes chyme with digestive enzymes. It is not classified as a named motility type of the large intestine. Option d is incorrect because while haustral contractions occur in the large intestine, this pairing omits mass movements entirely. Mass movements are essential for propelling material toward the rectum in preparation for defecation.

Correct Answer: Ascending, transverse, descending, sigmoid

Option b is correct because food residue leaving the cecum travels upward through the ascending colon, across the transverse colon, down the descending colon, and through the sigmoid colon before reaching the rectum. Option a is incorrect because the transverse colon does not come first after the cecum. Material must first travel upward through the ascending colon on the right side before crossing the abdomen horizontally. Option c is incorrect because the descending colon does not directly follow the ascending colon in the pathway. The transverse colon must be crossed horizontally before material descends along the left side of the abdomen. Option d is incorrect because the sigmoid colon is the final colonic segment before the rectum and does not come first. Placing it at the beginning completely reverses the actual anatomical sequence of the colon.

Correct Answer: Rectum

Option d is correct because the defecation reflex is triggered when the walls of the rectum become stretched by accumulating feces. This distension activates stretch receptors that send signals initiating the urge to defecate. Option a is incorrect because the sigmoid colon is a transit passageway connecting the descending colon to the rectum. While material passes through it during transit, the sigmoid colon does not trigger the defecation reflex. Option b is incorrect because the cecum is the initial receiving chamber of the large intestine located near the ileocecal valve. It is positioned far too proximally in the digestive tract to initiate defecation reflexes. Option c is incorrect because the descending colon transports material downward along the left side of the abdominal cavity. It serves a transit function and its stretching does not initiate the defecation reflex response.

Correct Answer: Emulsifies fats to increase lipase access

Option c is correct because the liver produces bile, which emulsifies large fat globules into smaller droplets. This increases the surface area available for pancreatic lipase to effectively complete the digestion of dietary fats. Option a is incorrect because protein digestion into peptides is performed by enzymes like pepsin in the stomach and trypsin in the small intestine. Neither of these protein-digesting enzymes is a product of the liver. Option b is incorrect because the conversion of pepsinogen into active pepsin is accomplished by hydrochloric acid secreted by parietal cells in the stomach lining, not by any substance that the liver produces. Option d is incorrect because neutralizing acidic chyme is primarily the role of bicarbonate ions secreted by the pancreas and alkaline mucus from Brunner glands in the duodenum, not a function of liver bile.

Correct Answer: Below diaphragm in right upper quadrant

Option a is correct because the liver is the largest gland in the human body and is located inferior to the diaphragm. It primarily occupies the right upper quadrant of the abdominal cavity. Option b is incorrect because the organ located posterior to the stomach is the pancreas rather than the liver. The liver predominantly occupies the right upper quadrant, not the left upper quadrant of the abdomen. Option c is incorrect because the liver sits below the diaphragm, not above it. It also occupies the upper quadrant of the abdomen, not the lower quadrant as described in this incorrect answer option. Option d is incorrect because the liver is not beside the spleen. The spleen sits in the left upper quadrant while the liver primarily occupies the right side of the upper abdominal cavity.

Correct Answer: Impaired fat digestion and chyme buffering

Option d is correct because a blockage at the hepatopancreatic ampulla prevents both bile and pancreatic juices from entering the duodenum. This impairs fat emulsification and removes the bicarbonate needed to buffer acidic chyme. Option a is incorrect because salivary amylase is produced by salivary glands in the oral cavity and pepsin is activated in the stomach. Neither substance passes through the hepatopancreatic ampulla to reach its target site. Option b is incorrect because vitamin absorption in the ileum depends on intrinsic factor and specific intestinal transport mechanisms. These processes operate independently of bile or pancreatic juice delivery through the hepatopancreatic ampulla. Option c is incorrect because gastric acid is produced by parietal cells and intrinsic factor is secreted in the stomach lining. Both gastric functions are completely independent of the hepatopancreatic ampulla and the ductal system.

Correct Answer: CCK triggers the gallbladder to contract

Option b is correct because when fatty chyme enters the duodenum, cholecystokinin is released and signals the gallbladder to contract. This pushes stored concentrated bile through the cystic duct and into the duodenum. Option a is incorrect because while the liver continuously produces bile, gastrin is a hormone that primarily stimulates gastric acid secretion and stomach motility. Gastrin does not directly trigger the release of stored bile. Option c is incorrect because secretin primarily stimulates the pancreas to release bicarbonate-rich fluid for neutralizing acidic chyme in the duodenum. It does not directly signal the stomach to empty its contents. Option d is incorrect because pepsin is a protein-digesting enzyme that is active only in the stomach. It is not a hormone and has no hormonal signaling function that could trigger bile duct opening.

Correct Answer: Lipoproteins that surround lipid molecules

Option c is correct because the liver produces lipoproteins, which are protein molecules that encapsulate hydrophobic lipid molecules. This packaging allows fats to be safely transported through the aqueous blood plasma environment. Option a is incorrect because bile salts function within the duodenum to emulsify dietary fats during digestion. They do not dissolve fats in blood plasma for systemic transport throughout the body via the circulatory system. Option b is incorrect because glycogen is the storage form of glucose rather than fat. The liver stores glycogen for blood sugar regulation, but glycogen plays no role in transporting lipid molecules through blood. Option d is incorrect because while albumin can bind some fatty acids in the blood, the liver specifically synthesizes lipoproteins as the primary dedicated vehicle for packaging and transporting lipid molecules through the circulation.

Correct Answer: It has both exocrine and endocrine roles

Option a is correct because the pancreas performs exocrine functions by secreting digestive enzymes through the pancreatic duct into the duodenum, and endocrine functions by releasing insulin and glucagon directly into the bloodstream. Option b is incorrect because bile production is a function of the liver and glycogen storage is also primarily a liver function. The pancreas does not produce bile or serve as a glycogen storage organ. Option c is incorrect because nutrient absorption and mucus secretion are functions associated with the small intestine and its goblet cells. The pancreas delivers enzymes to the intestine but does not absorb nutrients itself. Option d is incorrect because churning food and releasing gastric acid are specific functions of the stomach. The muscularis layer drives churning while parietal cells secrete hydrochloric acid, all within the stomach.

Correct Answer: Pancreatic amylase, pancreatic lipase, trypsin

Option d is correct because pancreatic amylase digests carbohydrates, pancreatic lipase digests fats, and trypsin digests proteins. Together these three enzymes represent the complete pancreatic set that targets all three macronutrient types. Option a is incorrect because pepsin is secreted by chief cells in the stomach and salivary amylase is produced by salivary glands. Gastric lipase is a minor stomach enzyme rather than a pancreatic product. Option b is incorrect because bile salts are not digestive enzymes but are liver products that emulsify fats. Brush border enzymes are located on intestinal microvilli and are not secreted by the pancreas. Option c is incorrect because lactase, maltase, and sucrase are brush border enzymes embedded in the microvilli of the small intestine. They complete final carbohydrate digestion but are not produced by the pancreas.

Correct Answer: Beta cells and insulin

Option b is correct because beta cells in the pancreatic islets of Langerhans produce insulin, which moves glucose from blood into cells. Their destruction causes persistently high blood sugar and can lead to diabetes. Option a is incorrect because alpha cells produce glucagon, which raises blood sugar by mobilizing stored glucose into the bloodstream. Destruction of alpha cells would cause low blood sugar, not the elevated levels described. Option c is incorrect because parietal cells are in the gastric glands of the stomach and produce hydrochloric acid and intrinsic factor. They are not pancreatic cells and play no role in glucose regulation. Option d is incorrect because G-cells are found in the stomach lining and secrete gastrin to stimulate gastric acid production. They have no involvement in blood glucose regulation or any pancreatic endocrine function whatsoever.

Correct Answer: Secretin from duodenal cells

Option c is correct because secretin is released by duodenal cells when acidic chyme arrives from the stomach. It stimulates the pancreas to secrete bicarbonate-rich fluid that neutralizes acid and protects the intestinal lining. Option a is incorrect because gastrin is released by G-cells in the stomach and primarily stimulates gastric acid secretion and increased motility. It does not trigger the pancreas to release bicarbonate for chyme neutralization. Option b is incorrect because CCK primarily stimulates gallbladder contraction to release bile and promotes pancreatic enzyme secretion. It is not the primary hormonal trigger for the release of bicarbonate to neutralize acid. Option d is incorrect because pepsinogen is an inactive enzyme precursor released by chief cells in the stomach. It is not a hormone and cannot send signals to the pancreas or any other organ.

Correct Answer: Insulin stores glucose, glucagon releases it

Option a is correct because insulin is secreted during the absorptive state and moves glucose from blood into cells for storage. Glucagon is secreted during fasting to mobilize stored glucose into the bloodstream. Option b is incorrect because this statement completely reverses the actual roles of both hormones. Insulin promotes glucose storage while glucagon promotes glucose release from storage, which is the exact opposite of what this claims. Option c is incorrect because insulin and glucagon have opposing effects on blood sugar and do not work in the same direction. Insulin lowers blood sugar while glucagon raises it, maintaining homeostatic balance together. Option d is incorrect because insulin actually lowers blood sugar by facilitating glucose uptake into body cells, while glucagon raises blood sugar by releasing stored glucose. This option assigns the wrong effect to each hormone.

Correct Answer: Small intestine

Option d is correct because the small intestine is where the most extensive chemical digestion occurs. Pancreatic enzymes and brush border enzymes work together here to break down all three macronutrients into absorbable monomers. Option a is incorrect because the oral cavity only initiates chemical digestion of carbohydrates through salivary amylase acting on starches. It does not participate in protein or lipid digestion and handles a small fraction overall. Option b is incorrect because the stomach primarily performs chemical digestion of proteins using pepsin and hydrochloric acid. It contributes only minor fat digestion and does not complete breakdown of all macronutrient classes. Option c is incorrect because the large intestine does not perform significant chemical digestion of macronutrients. Its primary roles are absorbing water and electrolytes, with only minor bacterial fermentation of remaining dietary fiber.

Correct Answer: Amylases target carbs, lipases target fats

Option c is correct because amylases specifically break down carbohydrates into simpler sugars, lipases break down fats into fatty acids and glycerol, and proteases break down proteins into individual amino acid building blocks. Option a is incorrect because amylases actually target carbohydrates rather than proteins, and lipases target fats rather than carbohydrates. This option reverses the correct substrate assignments for both enzyme classes in the pair. Option b is incorrect because proteases digest proteins rather than fats, and amylases digest carbohydrates rather than proteins. This option incorrectly swaps the target substrate for each of the two enzyme classes mentioned. Option d is incorrect because lipases are specific to fat digestion and proteases are specific to protein digestion. This option reverses the actual target molecules for both named enzyme classes, making both assignments factually wrong.

Correct Answer: Trypsin

Option b is correct because trypsin is the key pancreatic enzyme for protein digestion in the small intestine. It also activates other proteases, making its deficiency particularly damaging to intestinal protein breakdown. Option a is incorrect because pancreatic amylase digests carbohydrates in the small intestine rather than proteins. A deficiency of this enzyme would impair starch digestion but would not explain poor protein breakdown observed. Option c is incorrect because salivary amylase is produced by salivary glands in the oral cavity and initiates carbohydrate digestion only. It plays no role in protein digestion at any location along the digestive tract. Option d is incorrect because gastric lipase is a stomach enzyme involved in minor fat digestion only. It does not participate in protein digestion and is not a pancreatic enzyme, making it irrelevant here.

Correct Answer: Chemical digestion converts polymers to monomers

Option d is correct because chemical digestion specifically uses enzymes to break covalent bonds within polymers, converting large molecules like polysaccharides and polypeptides into their individual monomer building blocks that can be absorbed. Option a is incorrect because mechanical digestion does not use enzymes. It physically breaks food into smaller particles through chewing and churning without changing chemical structure of the food molecules being processed. Option b is incorrect because chemical digestion does not physically reduce food particle size. That function belongs to mechanical digestion, which uses physical forces like chewing, churning, and segmentation to break food apart. Option c is incorrect because only chemical digestion produces monomers from polymers through enzymatic bond-breaking. Mechanical digestion creates smaller physical pieces but cannot change molecular structure or produce monomers from food.

Correct Answer: Salivary amylase

Option a is correct because salivary amylase is the enzyme present in saliva that initiates carbohydrate digestion in the oral cavity by beginning to break polysaccharides and plant starches into simpler sugar molecules. Option b is incorrect because pancreatic lipase is secreted by the pancreas into the small intestine and digests fats, not carbohydrates. It acts much later in the digestive process on a different macronutrient entirely. Option c is incorrect because pepsin is the active protein-digesting enzyme in the acidic stomach environment that breaks peptide bonds within proteins. It has no role in carbohydrate digestion at any digestive tract location. Option d is incorrect because trypsin is a pancreatic protease that digests proteins in the small intestine. It is not present in the oral cavity and does not participate in carbohydrate digestion at any point.