Ch. 23 Digestive System Flashcards
(31 cards)
Which of these organs is not considered an accessory digestive structure?
A) Mouth
B) Salivary glands
C) Pancreas
D) Liver
A) Mouth.
Explanation: The mouth is part of the alimentary canal, the continuous muscular tube that food travels through. It is not an accessory organ because it directly handles the ingestion of food.
Incorrect Answers:
B) Salivary glands: These are accessory organs that secrete saliva to help break down food chemically.
C) Pancreas: An accessory organ that secretes digestive enzymes into the small intestine.
D) Liver: Produces bile, which aids in the digestion of fats, making it an accessory organ.
Which of the following organs is supported by a layer of adventitia rather than serosa?
A) Esophagus
B) Stomach
C) Small intestine
D) Large intestine
A) Esophagus.
Explanation: The esophagus lies outside the peritoneal cavity and is anchored by a layer of adventitia, a connective tissue layer that attaches it to surrounding structures.
Incorrect Answers:
B) Stomach: Covered by a serosa (visceral peritoneum) as it is within the peritoneal cavity.
C) Small intestine: Also surrounded by serosa in most regions.
D) Large intestine: Mostly covered by serosa, except in retroperitoneal portions where adventitia may be present, but not consistently like in the esophagus.
Which of the following membranes covers the stomach?
A) Falciform ligament
B) Mesocolon
C) Parietal peritoneum
D) Visceral peritoneum
D) Visceral peritoneum.
Explanation: The visceral peritoneum is the inner layer of the peritoneum that wraps around the external surface of most digestive organs, including the stomach.
Incorrect Answers:
A) Falciform ligament: Connects the liver to the anterior abdominal wall; unrelated to the stomach.
B) Mesocolon: Attaches the colon to the posterior abdominal wall; not associated with the stomach.
C) Parietal peritoneum: Lines the abdominal cavity wall, not the organs themselves.
The (BLANK) system benefits the digestive system by (BLANK).
A) Lymphatic, Endocrine hormones that help regulate secretion in digestive glands and accessory organs
B) Integumentary, Sensory and motor neurons that help regulate secretions and muscle contractions in the digestive tract
C) Nervous, Sensory and motor neurons that help regulate secretions and muscle contractions in the digestive tract
D) Nervous, Respiratory organs that provide oxygen and remove carbon dioxide
C) Nervous, Sensory and motor neurons that help regulate secretions and muscle contractions in the digestive tract.
Explanation: The nervous system regulates digestion by using, (1) Sensory neurons to detect stretch, chemical changes, and contents of the digestive tract, and (2) Motor neurons to control muscle contractions (peristalsis) and glandular secretions.
Incorrect Answers:
A) Lymphatic: Involved in immune response and lipid absorption, not hormone secretion regulation.
B) Integumentary: Not directly related to digestive regulation.
D) Nervous, Respiratory: The respiratory system handles gas exchange, not digestive tract regulation.
Which of these processes occurs in the mouth?
A) Ingestion
B) Mechanical digestion
C) Chemical digestion
D) All of the above
D) All of the above.
Explanation: In the mouth, food is ingested, mechanically broken down by chewing (mechanical digestion), and chemically broken down by salivary enzymes like amylase (chemical digestion).
Which of these processes occurs throughout most of the alimentary canal?
A) Ingestion
B) Propulsion
C) Segmentation
D) Absorption
B) Propulsion.
Explanation: Propulsion, including swallowing and peristalsis, moves contents along the alimentary canal and occurs throughout most of it.
Incorrect Answers:
A) Ingestion: Occurs only in the mouth.
C) Segmentation: Limited mostly to the small intestine.
D) Absorption: Primarily occurs in the small and large intestines.
Which of the following stimuli activates sensors in the walls of digestive organs?
A) Breakdown products of digestion
B) Distension
C) pH of chyme
D) All of the above
D) All of the above.
Explanation: Sensory receptors in the digestive tract respond to chemical and mechanical stimuli, including nutrient concentration (breakdown products), stretch (distension), and pH.
Which of these statements about reflexes in the GI tract is false?
A) Short reflexes are provoked by nerves near the GI tract
B) Short reflexes are mediated by the enteric nervous system
C) Food that distends the stomach initiates long reflexes
D) Long reflexes can be provoked by stimuli originating outside the GI tract
C) Food that distends the stomach initiates long reflexes.
Explanation: Food distending the stomach activates short reflexes, which are controlled entirely by the enteric nervous system—a local nerve network.
Incorrect Answers:
A) Short reflexes are provoked by nerves near the GI tract: True.
B) Short reflexes are mediated by the enteric nervous system: True.
D) Long reflexes can be provoked by stimuli originating outside the GI tract: True; for example, thought or smell of food.
Which of these ingredients in saliva is responsible for activating salivary amylase?
A) Mucus
B) Phosphate ions
C) Chloride ions
D) Urea
C) Chloride ions.
Explanation: Chloride ions are necessary to activate salivary amylase, which begins carbohydrate digestion.
Incorrect Answers:
A) Mucus: Lubricates food but does not activate enzymes.
B) Phosphate ions: Help buffer pH but do not activate enzymes.
D) Urea: Waste product; not involved in enzyme activation.
Which of these statements about the pharynx is true?
A) It extends from the nasal and oral cavities superiorly to the esophagus anteriorly
B) The oropharynx is continuous superiorly with the nasopharynx
C) The nasopharynx is involved in digestion
D) The laryngopharynx is composed partially of cartilage
B) The oropharynx is continuous superiorly with the nasopharynx.
Explanation: The oropharynx lies inferior to the nasopharynx and superior to the laryngopharynx.
Incorrect Answers:
A) Incorrect: The esophagus lies posterior to the trachea, not anterior.
C) Incorrect: The nasopharynx is not involved in digestion; only the oropharynx and laryngopharynx are.
D) Incorrect: The laryngopharynx is composed of muscle, not cartilage.
Which structure is located where the esophagus penetrates the diaphragm?
A) Esophageal hiatus
B) Cardiac orifice
C) Upper esophageal sphincter
D) Lower esophageal sphincter
A) Esophageal hiatus.
Explanation: The esophageal hiatus is the opening in the diaphragm through which the esophagus passes.
Incorrect Answers:
B) Cardiac orifice: This is the opening between the esophagus and the stomach.
C) Upper esophageal sphincter: Located at the top of the esophagus, near the pharynx.
D) Lower esophageal sphincter: Located just below the diaphragm, not at the point of penetration.
Which phase of deglutition involves contraction of the longitudinal muscle layer of the muscularis?
A) Voluntary phase
B) Buccal phase
C) Pharyngeal phase
D) Esophageal phase
D) Esophageal phase.
Explanation: The esophageal phase is involuntary and involves peristalsis, including contraction of the longitudinal muscles to push the bolus downward.
Incorrect Answers:
A) Voluntary phase: Involves the conscious action of the tongue.
B) Buccal phase: Same as the voluntary phase; it does not involve muscularis contraction.
C) Pharyngeal phase: Involves pharyngeal constrictors but not the muscularis of the esophagus.
The (BLANK) is the midline mucous membrane fold that attaches the inner surface of the lips to the gums.
A) Labial frenulum
B) Laryngopharynx
C) Micelle
D) Nucleosidase
A) Labial frenulum.
Explanation: The labial frenulum is the midline mucous membrane fold that attaches the inner surface of the lips to the gums.
Incorrect Answers:
B) Laryngopharynx: Part of the pharynx involved in both respiration and digestion, unrelated to lips or gums.
C) Micelle: A fat-transport structure formed in the small intestine, unrelated to oral anatomy.
D) Nucleosidase: An enzyme involved in the digestion of nucleic acids, not a structure in the mouth.
Which of these cells secrete hormones?
A) Parietal cells
B) Mucous neck cells
C) Enteroendocrine cells
D) Chief cells
C) Enteroendocrine cells.
Explanation: Enteroendocrine cells in the stomach secrete hormones like gastrin that regulate digestion.
Incorrect Answers:
A) Parietal cells: Secrete HCl and intrinsic factor.
B) Mucous neck cells: Secrete mucus.
D) Chief cells: Secrete pepsinogen and gastric lipase.
Where does the majority of chemical digestion in the stomach occur?
A) Fundus and body
B) Cardia and fundus
C) Body and pylorus
D) Body
C) Body and pylorus.
Explanation: The body is the main site of enzymatic secretion, and the pylorus grinds food and continues digestion before chyme enters the duodenum.
Incorrect Answers:
A) Fundus and body: Fundus mainly stores gas; not a major site of digestion.
B) Cardia and fundus: Cardia allows entry of food, minimal digestion happens here.
D) Body: Partially correct, but excludes the pylorus which plays an important role.
During gastric emptying, chyme is released into the duodenum through the (BLANK).
A) Esophageal hiatus
B) Pyloric antrum
C) Pyloric canal
D) Pyloric sphincter
D) Pyloric sphincter.
Explanation: The pyloric sphincter regulates the passage of chyme from the stomach into the duodenum during gastric emptying.
Incorrect Answers:
A) Esophageal hiatus: The opening in the diaphragm for the esophagus—not involved in chyme release.
B) Pyloric antrum: A region of the stomach leading to the canal, not the exit point.
C) Pyloric canal: A narrow region before the sphincter, not the structure controlling emptying.
Parietal cells secrete (BLANK).
A) Gastrin
B) Hydrochloric acid
C) Pepsin
D) Pepsinogen
B) Hydrochloric acid.
Explanation: Parietal cells secrete hydrochloric acid (HCl), which lowers stomach pH and activates pepsinogen into pepsin.
Incorrect Answers:
A) Gastrin: A hormone secreted by G cells, not parietal cells.
C) Pepsin: The active form of pepsinogen, secreted by chief cells, not parietal cells.
D) Pepsinogen: Secreted by chief cells, not parietal cells.
In which part of the alimentary canal does most digestion occur?
A) Stomach
B) Proximal small intestine
C) Distal small intestine
D) Ascending colon
B) Proximal small intestine.
Explanation: Most chemical digestion occurs in the duodenum and jejunum—the proximal (near center) small intestine—where enzymes and bile act on chyme.
Incorrect Answers:
A) Stomach: Begins protein digestion but doesn’t perform most digestion.
C) Distal small intestine: Primarily absorbs remaining nutrients, especially bile salts and vitamin B12.
D) Ascending colon: Involved in water and electrolyte absorption, not digestion.
Which of these is most associated with villi?
A) Haustra
B) Lacteals
C) Bacterial flora
D) Intestinal glands
B) Lacteals.
Explanation: Lacteals are lymphatic capillaries within villi that absorb dietary lipids.
Incorrect Answers:
A) Haustra: Pouches in the large intestine, unrelated to villi.
C) Bacterial flora: Reside in the large intestine, not associated with villi.
D) Intestinal glands: Located between villi, not part of them.
What is the role of the small intestine’s MALT?
A) Secreting mucus
B) Buffering acidic chyme
C) Activating pepsin
D) Preventing bacteria from entering the bloodstream
D) Preventing bacteria from entering the bloodstream.
Explanation: MALT (mucosa-associated lymphoid tissue) in the small intestine contains immune cells that monitor and defend against pathogens.
Incorrect Answers:
A) Secreting mucus: Done by goblet cells.
B) Buffering acidic chyme: Performed by bicarbonate in pancreatic juice.
C) Activating pepsin: Occurs in the stomach, not the small intestine.
Which part of the large intestine attaches to the appendix?
A) Cecum
B) Ascending colon
C) Transverse colon
D) Descending colon
A) Cecum.
Explanation: The appendix is a blind-ended tube attached to the cecum, the first section of the large intestine.
Incorrect Answers:
B) Ascending colon: Comes after the cecum and does not attach to the appendix.
C) Transverse colon: Located farther along the colon and not connected to the appendix.
D) Descending colon: Also not associated with the appendix.
Which of these statements about bile is true?
A) About 500 mL is secreted daily
B) Its main function is the denaturation of proteins
C) It is synthesized in the gallbladder
D) Bile salts are recycled
D) Bile salts are recycled.
Explanation: Bile salts are reabsorbed in the ileum and returned to the liver for reuse in a process called enterohepatic circulation.
Incorrect Answers:
A) About 500 mL is secreted daily: Incorrect; the liver secretes about 600–1000 mL daily.
B) Denaturation of proteins: This is a function of stomach acid, not bile.
C) It is synthesized in the gallbladder: Incorrect; bile is stored in the gallbladder but synthesized in the liver.
Pancreatic juice (BLANK).
A) Deactivates bile
B) Is secreted by pancreatic islet cells
C) Buffers chyme
D) Is released into the cystic duct
C) Buffers chyme.
Explanation: Pancreatic juice contains bicarbonate ions that neutralize acidic chyme entering the duodenum.
Incorrect Answers:
A) Deactivates bile: Incorrect; bile and pancreatic juice work together in digestion.
B) Islet cells: Incorrect; they produce hormones like insulin. Exocrine acinar cells produce pancreatic juice.
D) Cystic duct: Carries bile, not pancreatic juice.
Where are most fat-digesting enzymes produced?
A) Small intestine
B) Gallbladder
C) Liver
D) Pancreas
D) Pancreas.
Explanation: The pancreas produces pancreatic lipase, the main enzyme responsible for digesting fats in the small intestine.
Incorrect Answers:
A) Small intestine: Does not produce lipase; it absorbs fats but relies on enzymes from the pancreas.
B) Gallbladder: Stores and concentrates bile but does not produce enzymes.
C) Liver: Produces bile to emulsify fats, not enzymes to digest them.
