Examen digestivo

which statement about the digestive system is false?. Fully active digestive enzymes are limited in their location to the lumen (cavity). Indigestible materials never actually enter the body. Wavelike muscle contractions and sphincter muscles regulate movement throughout the system. transport is normally in one direction only. all of these statements about the digestive system are true.

which term best describes the process of swallowing food. ingestion. mastication. deglutition. absorption. defecation.

which is nor an accessory organ of the digestive system. stomach. salivary glands. liver. tongue. pancreas.

which is not a layer (tunic) found along the gastrointestinal (GI) tract?. mucosa. submucosa. capsule. muscularis. serosa.

which GI layer (tunic) features blood and lymphatic vessels, glands, and nerves?. mucosa. submucosa. capsule. muscularis. serosa.

the myenteric (Auerbach´s) plexus is a major nerve supply that innervates which layer of the gastrointestinal (GI) tract?. mucosa. submucosa. capsula. muscularis. serosa.

which statement about parasympathetic nerves of the gastrointestinal (GI) tract is false?. the vagus nerve stimulates and increase in motility (smooth muscle contractions) and secretions of the GI tract. the lower portion of the large intestine is innervated by spinal nerves emerging from the sacral region. preganglionic parasympathetic neurons synapse with postganglionic neurons at the submucosal plexus and myenteric plexus. parasympathetic stimulation decreases peristalsis and reduces GI secretions.

which description of the "intrinsic" or local regulation of the gastrointestinal (GI) tract is false. it works alone in controlling all processes of digestion and absorption. it relies upon instrinsic sensory neurons located within the gul wall. it may be called the enteric nervous system or the enteric brain. in includes paracrine regulatory molecules acting locally. it includes regulatory control by hormones secreted by the mucosal layer.

the pyloric sphincter is located at the end of the. esophagus leading into the stomach. stomach leading into the small intestine. pancreatic duct leading into the small intestine. common bile duct leading into the small intestine.

which statement about the esophagus is false. the esophagus pases through the thoracic cavity and through the diaphragm. the esophagus is lined with nonkeratinized stratified squamous epithelium. the upper one-third contains smooth muscle and the bottom one-third containsskeletal muscle. constriction of the lower esophageal (gastroesophageal sphincter) normally prevents stomach contents from regurgiting into the esophagus. all of these statements regarding the esophagus are true.

the antrum region of the stomach is most associated with which other region of the stomach?. cardiac. undus. body. pyloric. none of these terms is associated with the antrum.

which of the following is a true endocrine cell within the gastric glands of the stomach?. goblet cell. G cell. parietal cell. chief cell. enterochromaffin-like cell (ECL).

the gastric gland cell that secrete histamine and serotonin as paracrine regulators of the GI tract, are the. parietal cells. chief (or zymogenic) cells. enterochromaffin-like cells. G cells. D cells.

the_____ cells of the gastric gllands secrete the hormone gastrin; whereas the_____ cells secrete the hormone somatostatin. parietal; chief. enterochromaffin-like; D. chief; G. G; D. D; enterochromaffin-like.

Which function is not served by the presence of hydrochloric acid in the stomach (gastric) juices?. Hydrochloric acid denatures the tertiary structure of ingested proteins making them more digestible. Hydrochloric acid alters the structure of pepsinogen, resulting in activation of the enzyme, pepsin. Hydrochloric acid partially digests carbohydrate and fat molecules as well as protein molecules in chyme. Hydrochloric acid is the ideal (optimum) pH for maximum pepsin activity. All of these functions are served by the acidic gastric juice.

Which mechanism does not explain how the stomach mucosa resists self-digestion and ulcer formation?. The gastric mucosa is lined by a thin layer of alkaline mucus that contains bicarbonate buffer. The gastric mucosa cells are very impermeable to the acid in the stomach lumen. The entire epithelial lining is replaced every three days. Buffers are released from Brunner’s glands and the pancreas to neutralize the stomach acids. All of these mechanisms help resist self-digestion and ulcer formation in the stomach.

The longest portion of the small intestine is the. duodenum. ileum. jejunum.

Bile salts, vitamin B12, water, and electrolytes are absorbed primarily by the. jejunum. ileum. duodenum.

Which structure does not increase the surface area for absorption in the small intestine?. rugae. plicae circularis. villi. microvilli. None of these structures increase the small intestine surface area.

Absorbed fat enters the unique lymphatic vessels in the lamina propria core of each villus known as. villi capillaries. microvilli. central lacteals. intestinal crypts (of lieberkühn). plicae circularis.

Which statement about microvilli is false?. They are fingerlike projections formed by the foldings of the epithelial cell membrane itself. In the light microscope, they appear as a vague “brush border” along the luminal border of the columnar epithelial cells of the intestinal mucosa layer. “Fixed” digestive enzymes attached to the membranes of microvilli face the lumen and hydrolyze various substrates in chyme. They may activate pancreatic juice enzymes such as trypsin, that flow into the intestine. All of these statements regarding microvilli are true.

Which statement about smooth muscle in the small intestine is false?. They are connected to each other by an electrical synapses known as a nexuses. Pacesetter potentials, or slow waves, are spontaneous depolarizations that, like excitatory postsynaptic potentials (EPSPs) between neurons, weaken as they travel. Pacesetter potentials, when depolarized to a threshold, can fire action potentials that cause contraction in smooth muscle cells. The frequency and strength of smooth muscle contractions are increased by stimulation of autonomic sympathetic nerves. e. All of these statements regarding small intestine smooth muscle are true.

Chyme from the ileum passes into the_____of the large intestine; leading to an increase in pressure in the final section, or_____before exiting through the anus. colon; cecum. sigmoid colon; cecum. cecum; rectum. ascending colon; sigmoid colon. sigmoid colon; rectum.

Which statement about the large intestine, or colon, is false?. The colon is covered by columnar epithelium cells interspersed with mucus-secreting goblet cells. Like the small intestine, the epithelium of the large intestine also forms crypts of Lieberkühn. There are no villi present in the large intestine. Bulges or pouches of the outer surface form pouches, called haustra. All of these statements about the colon are true.

The vermiform appendix is a thin outpouching of the. Cecum. ascending colon. transverse colon. sigmoid colon. rectum.

The total volume of water excreted in the feces each day is about. 200 ml. 500ml. 1.0L. 1.5L. 2.0L.

Which analogy between the intestine and the kidney is false?. Both areas contain tight junctions between adjacent epithelial cells. Both areas have Na+/K+ active transport pumps in the basolateral membranes. Both areas can both secrete water into the lumen as well as absorb (or conserve) water. Both areas have receptors for the hormone aldosterone, which stimulates salt and water reabsorption. Both areas contribute to the loss of water from the body as a way of excreting other waste materials.

Which of the following is not a direct cause of diarrhea. cholera. celiac sprue. appendicitis. lactose intolerance.

As part of the reticuloendothelial system, the Kupffer cells in the liver are responsible for the. synthesis and secretion of bile. phagocytosis of blood swirling within the sinusoids. metabolism of carbohydrates and lipids. synthesis of large plasma proteins. torage of particular vitamins.

Which statement about the functional unit of the liver, known as the liver lobules, is false?. A central vein collects mixed blood from the sinusoids to help form the hepatic vein. Incoming blood from the hepatic artery and from the portal vein mix in the sinusoids. Bile is made and released into the central vein of each lobule. Liver lobules are destroyed by diseases such as cirrhosis. All of these statements regarding liver lobules are true.

The enterohepatic circulation refers to the specific pathway of many compounds, that are. absorbed from the intestine; and then travel to the liver. carbohydrate and lipid metabolism. synthesis of proteins. synthesis and secretion of bile. All of these are major liver functions.

Which of the following is not a major function of the liver?. detoxication of blood. carbohydrate and lipid metabolism. synthesis of proteins. synthesis and secretion of bile. All of these are major liver functions.

Which statement about substance called bilirubin is false?. Bilirubin is a pigment secreted from the liver in bile. Bilirubin is derived from liver cholesterol molecules. Bilirubin is bound to albumin in the bloodstream since it is not very water-soluble. In the intestine, bacteria convert bilirubin into another pigment called urobilinoge. Bilirubin can be conjugated (combined) with glucuronic acid to change its solubility properties.

As part of bile secretions, the bile acids are compounds derived from. sodium and potassium compounds. cholesterol. bilirubin. lecithin. None of these form bile acids.

Which statement about jaundice is false?. Jaundice is due to high levels of either free or conjugated bilirubin in the blood. Jaundice may be due to the excessive destruction of white blood cells in newborn babies. Jaundice may be seen in premature infants with inadequate amounts of liver enzymes. Jaundice may be seen in adults whose bile ducts are blocked by gallstones. Jaundice is seen in newborn babies who suffer from erythroblastosis fetalis.

Which route of elimination is not used primarily by the liver?. excretion of compounds in the bile. excretion of compounds in the urine. phagocytosis by Kupffer cells lining the sinusoids. chemical alteration (detoxication) within the hepatocytes. All of these routes are used by the liver.

Which detoxication reaction is not used by the liver. Toxic ammonia molecules are converted into less toxic urea molecules. Toxic porphyrins are converted into the yellow pigment, bilirubin. Toxic organic acids are converted to pH stabilizing bases. Toxic steroid hormones and other nonpolar compounds (drugs) are converted to polar (more water-soluble) ones. All of these reactions occur in the liver.

The plasma protein that is most common (70% of all plasma protein) and is responsible for much of the colloid osmotic (oncotic) pressure of blood, is. albumin. K-globulin. fibrinogen. prothrombin. angiotensinogen.

Which statement about the gallbladder is false?. The gallbladder’s major function is to store and concentrate bile. The gallbladder’s storage capacity is about 35-100 ml of bile. Bile accumulates in the gallbladder only when the sphincter of Oddi is closed. When full, the gallbladder is the shape of a small pear. Contraction of the muscular gallbladder ejects bile through the common bile duct and into the stomach.

Which statement about the digestive enzymes secreted by the acini of the pancreas, is false?. These enzymes digest ingested carbohydrates, proteins, and triglycerides. These enzymes are mostly produced as inactive molecules (zymogens) that become active in the small intestine. Enterokinase is one of the more important pancreatic enzymes. Activated trypsin activates many of the other pancreatic zymogens. All of these statements regarding pancreatic enzymes are true.

During the cephalic phase of gastric regulation. the brain exerts its reflex control via the vagus nerve. HCl is secreted from chief cells. pepsinogen is secreted from parietal cells. gastrin is secreted from enterochromaffin-like cells.

Which statement about the gastric phase is false?. The gastric phase exhibits both positive and negative feedback mechanisms that occur as protein arrives in the stomach. The presence of fat in the stomach chyme, but not glucose, stimulates gastric acid secretion. As the pH of the gastric juice drops (acid levels rise), the secretion of gastrin hormones also drops, correspondingly. The amount of HCl and pepsinogen secreted by the stomach is directly proportional to the amount of short polypeptides and amino acids present in the chyme. The amount of acid secreted by the parietal cells of the stomach is closely matched to the amount of protein ingested.

Which statement about the intestinal phase is false?. The increased osmolality of chyme in the duodenum may inhibit gastric activity and secretion via nerve reflexes. Stretch (distension) caused by chyme entering the duodenum may inhibit gastric activity. The presence of protein polypeptides in intestinal chyme may stimulate the release of a hormone (enterogastrone) that inhibits gastric function. omatostatin, cholecystokinin (CCK) and glucagon-like peptide-1 (GLP-1) are polypeptide hormones that collectively serve to inhibit gastric activity. The presence of glucose in the intestinal chyme may cause GIP release, which, in turn stimulates the secretion of insulin from the islets of Langerhans.

Which statement about the enteric nervous system is false?. Because it contains about as many neurons as are found in the spinal cord, it is also known as the enteric brain. It contains afferent (sensory) neurons, and both sympathetic and parasympathetic neurons. Like the CNS, it contains many short, connecting interneurons. Like the CNS, it contains many glial (supporting) cell than neurons. All of these statements about the enteric nervous system are true.

Which of the following substances is a hormone that is produced not only by cells of the intestine, but by the brain and stomach as well?. somatostatin. enterogastrone. cholecystokinin (CCK). glucagon-like peptide-1 (GLP-1). guanylin.

Which locally controlled intestinal reflex results in the decrease in gastric motility in response to distension of the ileum with chyme. a. gastroileal reflex. b. ileogastric reflex. c. intestino-intestinal reflex. d. knee jerk reflex.

The arrival of chyme causes the reflex secretion of pancreatic juice and bile during the. a. cephalic phase. b. gastric phase. c. intestinal phase. d. progress through all of these phases.

The presence of___in chyme stimulates secretin release, while the presence of____in chyme stimulates cholecystokinin (CCK) release. a. acid; alkaline. b. acid; fat and protein. c. fat; protein and glucose. d. protein and fat; acid. e. alkaline; protein and glucose.

As chyme enters the duodenum, bile secretion is enhanced by. a. secretin secretion. b. enterogastrone secretion. c. CCK secretion. d. both a and b. e. both a and c.

The nutrients in foods that serve predominantly as “fuel food,” providing energy for metabolism are. a. vitamins, minerals, and carbohydrates. b. carbohydrates, lipids (fats), and vitamins. c. protein, lipids (fats), and water. d. carbohydrates, proteins, and lipids (fats). e. protein, vitamins, and carbohydrates.

Which statement about the digestion of protein in ingested food is false?. a. Protein digestion begins in the mouth with enzymes in saliva. b. The stomach enzyme, pepsin, only partially digests proteins. c. Most protein digestion occurs in the duodenum and jejunum. d. Peptide bonds between amino acids are broken by both endopeptidases and exopeptidases, depending upon their location along the protein chain. e. Microvilli brush border peptidase enzymes are also involved in protein digestion.

Which statement about the digestion of lipid in ingested food is false?. a. Lipid digestion begins in the duodenum with the digestion of large lipid globules into smaller globules. b. The emulsification process requires the mixture of lipids with bile. c. Mulsification digests lipids, forming free fatty acids and glycerol. d. Pancreatic enzymes, lipase and colipase, aid the hydrolysis of lipids. e. Mixed micelles of digested lipids are absorbed primarily by diffusion.

Which statement about the intestinal absorption or the transport of lipids in the blood is false?. a. Chylomicrons are lipid-protein particles formed within the intestinal epithelial cells during lipid absorption. b. Chylomicrons enter the lacteal of the intestinal villus for transport through lymphatic vessels. c. Absorbed lipids do not travel through the hepatic portal vein. d. Chylomicrons enter and blend with the general blood circulation via the thoracic duct. e. All of these statements regarding the intestinal absorption or the transport of lipids in the blood are true.

Parasympathetic stimulation increases gastrointestinal motility and sympathetic stimulation decreases motility. The autonomic nervous system controls gut motility by changing which of the following?. Gastrin secretion. Pacemaker discharge frequency. Secretin secretion. Slow wave frequency. Spike potential frequency.

The cephalic phase of gastric secretion accounts for about 30% of the acid response to a meal. Which of the following can totally eliminate the cephalic phase of gastric secretion?. Antacids (e.g., Rolaids). Anti-gastrin antibody. Atropine. Histamine H2 blocker. Vagotomy. Sympathectomy.

Which of the following ions has the highest concentration in saliva under basal conditions?. Bicarbonate. Chloride. Potassium. Sodium.

Which of the following is not normally found in abundance in the portal blood?. Amino acids. Glucose. Short-chain fatty acids. Triglycerides.

Mass movements are often stimulated after a meal by distention of the stomach (gastrocolic reflex) and distention of the duodenum (duodenocolic reflex). Mass movements often lead to which of the following?. Bowel movements. Gastric movements. Haustrations. Esophageal contractions. Pharyngeal peristalsis.

The gastric phase of gastric secretion accounts for about 60% of the acid response to a meal. Which of the following can virtually eliminate the secretion of acid during the gastric phase?. Antiacids (e.g., Rolaids). Antigastrin antibodies. Atropine. Histamine H2 blocker. Proton pump inhibitor.

Mass movements constitute an important intestinal event that lead to bowel movements. Mass movements cause which of the following?. Contraction of internal anal sphincter. Duodenal peristalsis. Gastric retropulsion. Hunger sensations. Rectal distension.

Swallowing is a complex process that involves signaling between the pharynx and swallowing center in the brainstem. Which of the following structures is critical for determining whether a bolus of food is small enough to be swallowed?. Epiglottis. Larynx. Palatopharyngeal folds. Soft palate. Upper esophageal sphincter.