Q1 Flashcards
Salivary secretion is stimulated by A) the salivary nucleus only. B) the salivary nucleus and gastrin. C)gastrin only. D)the salivary nucleus and local reflexes in the tunica mucosa and submucosa.
Salivary nucleus only
Feedback: Secretions along the digestive tract can be stimulated by the automatic nervous system, by local reflexes in the tunica mucosa and submucosa and by hormones. Typically secretions are stimulated by either the nervous system or release of hormones. Salivation, however, is only stimulated by the nervous system. The tactile stimulation in the oral cavity, stimulation of taste buds, as well as the smell or thought of food stimulates the salivary nucleus in the brainstem. Normal salivation is stimulated by the parasympathetic nervous system.
Surface area of the stomach is increased by A) gastric pits. B) plicae circulares. C)villi. D)microvilli.
Gastric pits
Feedback:
The small intestine’s surface area for digestion and absorption is increased by plicae circulares, villi and microvilli. In the stomach, gastric glands line the numerous tube-like gastric pits that increase the surface area for digestion.
The esophagus is different from the GI tract because the esophagus has
A) skeletal muscles at the superior end and smooth muscles at the inferior end.
B) no tunica submucosa.
C)villi and microvilli to increase surface area.
D)no tunica mucosa.
A
Feedback: The esophagus contains four tunics: mucosa, submucosa, muscularis, and adventitia. The tunica adventitia is different from the tunica serosa, because the tunica adventitia grades into the surrounding connective tissue. The tunica muscularis in the GI tract consists of smooth muscle only, while in the esophagus the superior part contains skeletal muscle and the inferior part contains smooth muscle.
Sometimes when you are talking and eating you initiate the gagging reflex. The gagging or coughing reflex is stimulated when foreign material enters the larynx. Some of the bolus you are swallowing enters the larynx when you are talking because the
A) epiglottis is not closed over the glottis.
B) soft palate moves inferiorly.
C) pharyngeal constrictor muscles relax.
D) esophageal sphincters relax.
A
In normal swallowing, the soft palate (particularly the uvula) moves superiorly, the pharyngeal constrictor muscles contract and the esophageal sphincters relax. If the soft palate moves inferiorly (you are breathing through your nose while swallowing) some of the bolus could enter the nasopharynx and initiate a sneezing reflex. When talking while swallowing, the epiglottis is open, which may allow some of the bolus to enter the larynx. This would initiate the gagging or coughing reflex
The cardiac or lower gastroesophageal sphincter is composed of \_\_\_\_\_\_\_\_\_\_\_\_ muscle and prevents chyme from moving into the \_\_\_\_\_\_\_\_\_\_\_\_\_. A) smooth; esophagus B) skeletal; esophagus C) smooth; duodenum D) skeletal; duodenum
A
Feedback:
Both the cardiac and pyloric sphincters are composed of smooth muscle. The pyloric sphincter regulates the movement of chyme into the duodenum and prevents the chyme from moving back into the stomach. The cardiac sphincter prevents chyme from moving into the esophagus. If this occurs, irritation of the esophagus or hearth burn may result.
Parasympathetic stimulation causes endocrine cells in the stomach to release the hormone A) gastrin. B) pepsinogen. C) histamine. D) secretin.
A
Feedback: Pepsinogen is an enzyme produced by chief cells in the stomach, while secretin is a hormone produced by endocrine cells in the duodenum. The endocrine cells of the stomach produce two major hormones: gastrin and histamine. Histamine stimulates parietal cells to secrete hydrochloric acid. Gastrin not only stimulates gastric secretions, but also increases gastric motility, relaxes the pyloric sphincter and stimulates the release of histamine.
After eating or drinking dairy products like cheese and milk, you have intestinal cramps, bloating and diarrhea. You most likely have A) lactose intolerance. B) diabetes mellitus, Type I. C) heartburn. D) peritonitis.
A
Feedback: In heartburn you feel pain in the area of the heart, because of the acid chyme from the stomach irritating the lining of the esophagus. Peritonitis is an infection or inflammation of the peritoneum, which is not be related to eating dairy products. Type I diabetes mellitus is a result of lack of adequate insulin production, and the symptoms include abnormally high glucose levels in the blood, glucose in the urine, and excessive urine production. The inability to digest the disaccharide, lactose, in dairy products is called lactose intolerance and results in intestinal cramps, bloating and diarrhea.
The lipids that can be absorbed across the epithelial wall of the small intestine are hydrophobic and would have a difficult time in the watery lumen to come in contact with the epithelial membrane. These lipids are able to move easily in the watery lumen because of interaction with A) bile salts. B) lipase. C) micelles. D) chylomicrons.
A
Feedback:
The lipid digestion products are fatty acids, glycerol, cholesterol and phospholipids. These are nonpolar or hydrophobic molecules in a medium of water, which is polar. Bile salts have hydrophobic ends that are directed toward the lipid products and hydrophilic ends directed outward toward the water environment. The complex is called a micelle and it allows for easy movement of the complex toward the epithelial wall and subsequent diffusion of the lipid products into the epithelial cell. A micelle can be seen in the below figure. (Figure 24.28)
Once absorbed into the epithelial cell of the small intestine, free fatty acids and glycerol are recombined and a protein coat is added to form a A) chylomicron. B) micelle. C) lipoprotein. D) fatty droplet.
A
A micelle is the package in the lumen of the small intestine formed by lipid digestion products surrounded by bile salts. Once lipids reach the blood they combine with proteins and the complex is called a lipoprotein. Fatty droplets are smaller molecules of lipids that are produced when bile salts emulsify large lipid molecules. When the intestinal cells absorb cholesterol and fatty acids, they are recombined in the smooth ER to form fat. The protein coat is added to the fat and other lipid products in the golgi apparatus. This new package is called a chylomicron, which leaves the cell by exocytosi
Most of the protein digesting enzymes are produced by the A) stomach and pancreas. B) small intestine and pancreas. C) stomach and small intestine. D) salivary glands and stomach.
A
Three major enzymes break down protein to peptides. Pepsinogen produced by chief cells in the stomach is activated to pepsin by the acid pH. Trypsinogen and chymotrypsinogen are produced by the acinar cells in the pancreas. Trypsinogen is activated by enterokinase in the small intestine to trypsin. Trypsin then activates chymotrypsinogen to chymotrypsin. So, the protein digesting enzymes are produced in the stomach (pepsinogen) and pancreas (trypsinogen and chymotrypsinogen). The last two enzymes become activated in the small intestine
Which one of the following hormones is released by both the stomach and small intestine? A) gastrin B) secretin C) cholecystokinin D) gastric inhibitory polypeptide
A
Feedback:
In the intestinal phase, in response to a chyme that has a pH below 2 or contains fatty acids, the endocrine cells of the duodenum release hormones to inhibit gastric secretions. These hormones include secretin (pH below 2), cholecystokinin (fatty acids), and gastric inhibitory polypeptide (fatty acids). An increase in protein in the chyme stimulates the endocrine cells of the duodenum to release gastrin. Gastrin is also released by the endocrine cells of the stomach and whether gastrin is released by the stomach or small intestine, gastric secretions are increased.
In the tunica mucosa and submucosa of the small intestine, a series of folds called the ____________ functions to __________________.
A) plicae circulares; increase surface area
B) villi; increase surface area
C) microvilli; allow the small intestine to expand
D) rugae; allow the small intestine to expand
A
Feedback:
The stomach contains folds called rugae in the tunica mucosa and submucosa, which allow the stomach to expand. The small intestine has several modifications that allow its surface area to increase about 600 fold over a tube that has no modifications. Microvilli are cytoplasmic extensions on individual epithelial cells, and villi are fingerlike projections of the tunica mucosa. The tunica mucosa and submucosa form a series of folds called circular folds or plicae circulares.
The lymphatic capillaries in the villi of the small intestine are called A) lacteals. B) Peyer's patches. C) Crypts of Lieberkuhn. D) microvilli.
A
Feedback:
Crypts of Lieberkuhn are tubular invaginations of the tunica mucosa in the small intestine while Peyer’s patches are lymph nodules in the tunica mucosa and submucosa of the ileum. Microvilli are cytoplasmic extensions on the absorptive cells. Villi are fingerlike projections that contain blood capillary networks and lymphatic capillaries called lacteals.
Bacteria and other foreign material absorbed by the small intestine are destroyed by \_\_\_\_\_\_\_\_\_\_\_ cells found lining the hepatic sinusoids. A) kupffer B) hepatic C) endothelial D) acinar
A
Feedback: The acinar cells are found in the pancreas and produce the enzymatic component of pancreatic juice. The hepatic cells or hepatocytes line the outside of the sinusoids and perform many functions including absorbing oxygen and nutrients, detoxifying materials like alcohol, storing as well as releasing nutrients back into the blood, and producing bile. Endothelial cells are very thin simple squamous cells making up the wall of the sinusoid along with kupffer cells or hepatic phagocytic cells that phagocytize bacteria and other foreign material.
Gall stones result from the precipitation of \_\_\_\_\_\_\_\_\_\_\_\_\_ in the gallbladder. A) cholesterol B) calcium salts C) uric acid salts D) urea
A
Feedback: Crystals of calcium salts may cause kidney stones, while crystals of uric acid salts may result in gout. Urea is very water-soluble and is less likely to form crystals. Cholesterol, which can be taken in via the diet and is also a waste product of saturated fat metabolism, is one of the components of bile. Cholesterol may precipitate out in the gallbladder and help to form gallstones. Drastic dieting with rapid weight loss may lead to gallstone production.
In the production of the aqueous component of pancreatic juice, \_\_\_\_\_\_\_\_\_ ions are actively transported into the intercalated duct and sodium ions are exchanged for \_\_\_\_\_\_\_\_\_ ions. A) bicarbonate; hydrogen B) sodium; potassium C) bicarbonate; potassium D) hydrogen; potassium
A
Feedback:
The aqueous component of pancreatic juice is composed of water, sodium ions, and bicarbonate ions. In the cells that line the intercalated duct, water and carbon dioxide are stimulated by the enzyme carbonic anhydrase to form carbonic acid. The carbonic acid dissociates into bicarbonate ions and hydrogen ions. Bicarbonate ions are actively transported into the intercalated duct. The hydrogen ions are exchanged for sodium ions between the cell and the capillary. Sodium ions and water follow the actively transported bicarbonate ions into the intercalated duct lumen by diffusion.
You have the following symptoms: sudden abdominal pain, slight fever, loss of appetite, and nausea. You may have A) appendicitis. B) heartburn. C) diarrhea. D) hemorrhoids.
A
Feedback:
Heartburn is chest pain associated with acid chyme from the stomach irritating the lining of the inferior esophagus. Hemorrhoids are inflammation of the hemorrhoidal veins, which supply the anal canal. This may result in pain, itching and bleeding around the anus. Diarrhea results when the large intestine is irritated and causes an abnormally frequent discharge of watery feces. Sudden abdominal pain (especially in the right lower portion), slight fever, loss of appetite, and nausea may be a result of inflammation of the vermiform appendix called appendicitis. Constipation or diarrhea may accompany appendicitis.
The coronary ligament attaches the
A) liver to the diaphragm.
B) liver to the anterior abdominal wall.
C) colon to the posterior body wall.
D) lesser curvature of the stomach and proximal end of the duodenum to the liver and diaphragm.
A
Feedback:
The falciform ligament attaches the liver to the anterior abdominal wall, and the mesocolon attaches the colon to the posterior abdominal wall. The lesser omentum attaches the lesser curvature of the stomach and proximal end of the duodenum to the liver and diaphragm. The mesentery that attaches the liver to the diaphragm is the coronary ligament.
The most common cause of tooth loss in adults is A) periodontal disease. B) gingivitis. C) pyorrhea. D) dental caries.
A
Feedback: Dental caries or tooth decay is caused by the break down of enamel by acids produced by bacteria. Gingivitis is inflammation of the gingiva and may lead to periodontal disease. Pyorrhea is a condition in which pus occurs with periodontal disease. Periodontal disease is the inflammation and degradation of the periodontal ligaments, gingiva, and alveolar bone and is the leading cause of tooth loss in adults.
In a given tooth, the dentin is located \_\_\_\_\_\_\_\_\_\_\_\_\_\_ to the enamel. A) inferior B) anterior C) superior D) posterior
A
dentin is located below or inferior to the enamel.
Salivary glands structurally are
A) compound tubuloacinar or tubuloalveolar glands.
B) compound alveolar or acinar glands.
C) compound tubular glands.
D) simple branched alveolar or acinar glands.
A
Salivary glands have ducts that are both tubular and alveolar or acinar in shape. Because the ducts branch repeatedly, the salivary glands are also compound.
Saliva decreases gingivitis and caries because it contains immunoglobulin A and A) lysozymes. B) mucus. C) salivary amylase. D) water.
A
Feedback: Saliva contains water, which liquefies the food and is the medium for digestion; mucus that lubricates the food and protects the epithelial cells and gives saliva a lubricating quality; and the salivary amylase, which breaks down starch to maltose and isomaltose. The antibacterial enzyme, lysozyme, is found in a number of secretions including saliva and tears. In the oral cavity this antibacterial enzyme reduces the occurrence of gingivitis and caries.
Secretion of the enzymatic component of pancreatic juice is stimulated by the hormone A) gastric inhibitory polypeptide. B) secretin. C) gastrin. D) cholecystokinin.
D
Feedback:
The endocrine cells of the duodenum produce four hormones. Gastrin and gastric inhibitory polypeptide increase gastric secretions and inhibit gastric secretions respectively. Secretin and cholecystokinin have a number of target organs, but the pancreas is stimulated by both. Secretin stimulates the cells lining the intercalated duct to secrete the aqueous component. Cholecystokinin stimulates the acinar cells to secrete the enzymatic component. Cholecystokinin is stimulated to be released by fatty acids and fat in the chyme of the small intestine.
This region of the large intestine has a simple columnar epithelium in its tunica mucosa, smooth muscle in its tunica muscularis, and epiploic appendages attach to its outer surface. This region is called the A) cecum. B) colon. C) rectum. D) anal canal.
B
Feedback:
The cecum, colon and rectum all have a simple columnar epithelium and smooth muscle in their tunica muscularis. The anal canal has smooth muscle but the epithelium changes from simple columnar to stratified squamous. Epiploic appendages are fat-filled connective tissue pouches unique to the colon.
In the colon, the teniae coli are bands of __________, which contract to form ___________.
A) fat; epiploic appendages
B) longitudinal smooth muscle; haustra
C) skeletal muscle; haustra
D) smooth muscle; the internal anal sphincter
B
Feedback:
The epiploic appendages are fat-filled connective tissue pouches attached to the outer surface of the colon. The anal canal contains smooth muscle that forms the internal anal sphincter. There is no skeletal muscle in the wall of the colon. The teniae coli are three bands of longitudinal smooth muscle that run the length of the colon. When the teniae coli contract, pouches called haustra form along the length of the colon.
This blind tube is about 9 cm long, is filled with lymph nodules and attaches to the cecum. This blind tube is called the A) epiploic appendix. B) haustra. C) vermiform appendix. D) tenia coli.
C
Feedback:
Epiploic appendages are fat-filled pouches attached to the outer surface of the colon. Haustra are pouches in the colon formed by contraction of three bands of longitudinal smooth muscle called teniae coli. The cecum is the proximal end of the large intestine and forms a blind sac. Attached to the cecum is a small blind tube about 9 cm long called the vermiform appendix.
Once chylomicrons leave the simple columnar epithelium of the small intestine, they diffuse into A) capillaries. B) lacteals. C) arterioles. D) venules.
B
Feedback:
Chylomicrons are large molecules composed of phospholipids, triglycerides, and cholesterol with a protein coat. Products are taken up from the interstitial fluid around the small intestine either by capillaries or by lymphatic capillaries called lacteals. The walls of arterioles and venules are too thick to allow for any absorption. The chylomicron is too big and too polar to enter the capillary. Lacteals have large spaces between their simple squamous cells that allow for the diffusion of the chylomicrons.
A lipoprotein has the following components: 5% tryglyceride, 20% cholesterol, 30% phospholipid, and 45% protein. This molecule would be best described as a A) micelle. B) chylomicron. C) low-density lipoprotein. D) high-density lipoprotein.
D
Feedback:
A micelle is composed of bile salts, fatty acids, glycerol, plus other lipid products, but it contain no protein. A chylomicron is composed of only about 1% protein. The chylomicron carries the fat products to the lacteals. When the fat products are released into the blood, they are carried by proteins. Lipids that combine with proteins in the blood form lipoproteins. Lipids are less dense than water while proteins are more dense than water. A chylomicron with only 1% protein is referred to as a very low-density lipoprotein (VLDL) whereas a lipoprotein with 45% protein would be a high-density lipoprotein (HDL).
Cholesterol that is required to produce steroids and bile salts is carried in A) micelles. B) chylomicrons. C) low-density lipoproteins (LDL). D) high-density lipoproteins (HDL).
C
Feedback:
About 15% of the cholesterol in the body is ingested in the food we eat, while the remaining 85% is manufactured by cells of the body. Cells have LDL receptors on their surfaces that bind to the low-density lipoproteins (LDL). Cholesterol transported to cells must be carried by LDL to allow for absorption into cells by endocytosis. Excess lipids are packaged in HDL and transported back to the liver for recycling or disposal.
Cholesterol is a major component of atherosclerotic plaque. Cholesterol carried by \_\_\_\_\_\_\_\_\_\_\_ is linked to coronary heart disease. A) micelle B) chylomicron C) low-density lipoprotein (LDL) D) high-density lipoprotein (HDL)
C
Feedback: Micelles carry cholesterol to the small intestinal epithelium, and chylomicrons carry cholesterol to lacteals. Most of the cholesterol in the blood attach to proteins forming lipoproteins - either low-density lipoproteins ( LDL) or high-density lipoproteins (HDL). Cholesterol carried in HDL is being carried to the kidneys for removal, and LDL carries cholesterol to the tissues. The higher the LDL levels, the more cholesterol is carried to the tissues and the higher the possibility of atherosclerotic plaque. The higher the HDL levels the more cholesterol is carried to the liver for disposal. Sometimes LDLs are called bad cholesterol carriers and HDLs are called good cholesterol carriers
The optimum pH for trypsin and chymotrypsin is about A) 1-3. B) 5-7. C) 7-9. D) 10-12
C
Feedback: There are different pH levels in the GI tract. The saliva has a pH between 6 and 7 where salivary amylase is active. The stomach has a pH between 1 and 3 where pepsin is active. The acid chyme is buffered by bicarbonate ions added to the duodenum by bile and pancreatic juices. The pH of the small intestine is about 8 where trypsin and chymotrypsin are most active.
Calcium is actively absorbed by the small intestine and this is accelerated by A) sodium. B) the intrinsic factor. C) Vitamin D. D) Vitamin K.
C
Feedback: Sodium, potassium, calcium, magnesium, and phosphate are actively transported into epithelial cells lining the small intestine. The intrinsic factor helps in the absorption of Vitamin B12. Most of the Vitamin K is produced by the colic bacteria in the large intestine, but Vitamin K is lipid-soluble and is easily absorbed. Vitamin D or calcitriol helps increase the active transport of calcium
Probably the main reason why elderly people have antacids, H2 antagonists and proton pump inhibitors is because of the increase in \_\_\_\_\_\_\_\_\_\_\_\_\_ with age. A) Crohn's disease B) irritable bowel syndrome C) gastroesophageal reflux disorder D) colitis
C
Feedback:
Crohn’s disease involves localized inflammatory degeneration anywhere along the GI tract. There are many causes of this, but smoking increases the risk the most. Irritable bowel syndrome is a disorder of unknown causes in which intestinal mobility is abnormal. Affected individuals have alternating bouts of constipation and diarrhea. Colitis is an inflammation of the colon. Antacids, H2 antagonists and proton pump inhibitors would not effect the three previous pathologies. Gastroesophageal reflux disorder (GERD) is caused by the movement of acid chyme from the stomach through the weak gastroesophageal sphincter back to the esophagus where it irritates the lining. The sph
Cholesterol is a major component of atherosclerotic plaque. Cholesterol carried by \_\_\_\_\_\_\_\_\_\_\_ is linked to coronary heart disease. A) micelle B) chylomicron C) low-density lipoprotein (LDL) D) high-density lipoprotein (HDL)
C
Feedback: Micelles carry cholesterol to the small intestinal epithelium, and chylomicrons carry cholesterol to lacteals. Most of the cholesterol in the blood attach to proteins forming lipoproteins - either low-density lipoproteins ( LDL) or high-density lipoproteins (HDL). Cholesterol carried in HDL is being carried to the kidneys for removal, and LDL carries cholesterol to the tissues. The higher the LDL levels, the more cholesterol is carried to the tissues and the higher the possibility of atherosclerotic plaque. The higher the HDL levels the more cholesterol is carried to the liver for disposal. Sometimes LDLs are called bad cholesterol carriers and HDLs are called good cholesterol carriers.
The lamina propria and muscularis mucosa are found in the tunica A) mucosa. B) submucosa. C) muscularis. D) serosa.
A
Feedback:
The lamina propria is composed of loose connective tissue, and the muscularis mucosae is a thin ring of smooth muscle controlled by Meissner’s or submucosal plexus.
The term gastrointestinal (GI) tract refers to the
A) oral cavity, pharynx, esophagus, stomach, small intestine and large intestine.
B) pharynx, esophagus, stomach, small intestine and large intestine.
C) esophagus, stomach, small intestine and large intestine.
D) stomach, small intestine and large intestine
D
The digestive tract consists of the oral cavity, pharynx, esophagus, stomach, small intestine, large intestine, and anus plus the following accessory organs: teeth, tongue, salivary or other oral glands, tonsils, mucous glands, liver, gallbladder, appendix and pancreas. The term GI tract just refers to the stomach, small intestine and large intestine
