Chapter 23 The Digestive System Flashcards
1
Q
wavelike smooth muscle contractions that move foodstuffs through the alimentary tube.
A
peristalsis
2
Q
chemical or mechanical process of breaking down foodstuffs into simpler units
A
digestion
3
Q
enzymatic breakdown of any type of food molecule
A
hydrolysis
4
Q
process by which simpler chemical units pass through the lumen of the gastrointestinal tract
A
absorption
5
Q
increases output of enzymatic rich pancreatic juice
A
cholecystokinin
6
Q
increases output of pancreatic juice rich in bicarbonate ions
A
secretin
7
Q
increases Hcl secretion and stimulates contraction of intestinal muscle
A
gastrin
8
Q
stimulates insulin release and mildly inhibits HCl production
A
gastric inhibitory peptide
9
Q
The relatively unchanging pressure in a filling stomach is due to the contraction of the stomach oblique muscle layer. False, why?
A
False, why.
10
Q
The pharyngeal-esophageal phase of swallowing is involuntary and is controlled by the swallowing center in the thalamus and lower pons. False, why?
A
medulla oblongata and pons
11
Q
Pepsinogen is the precursor to the gastric enzyme for protein digestions and is secreted by the parietal cells. False, why?
A
secreted by gastric chief cells
12
Q
The only essential function of the stomach is to begin the digestion of proteins. False, why?
A
One function*
13
Q
Peyer’s patches are primarily found in the submucosa of the duodenum. False, why?
A
mucosa and submucosa of ileum
14
Q
The submucosal nerve plexus provides the major nerve supply to the GI tract wall and controls GI mobility. False, why?
A
enteric nervous system
15
Q
Dentin anchors the tooth in place. False, why?
A
periodontal ligament
16
Q
The digestive function of the liver is to produce digestive enyzmes. False, why?
A
is to process the nutrients absorbed from small intestine
17
Q
The stomach’s contractile rhythm is set by pacemaker cells found in the spinal cord. False, why?
A
found in greater curvature region of fundus
18
Q
The soft palate reflexively opens the nasopharynx to allow the passage of food, which is now called a bolus. False, why?
A
soft palate rises to prevent food from entering nose
19
Q
When swallowing, the glottis covers the epiglottis. False, why?
A
covers the larynx
20
Q
Most gastric ulcers are due to excessive production oh hydrochloric acid. False, why?
A
due to h pylori bacteria
21
Q
The enterohepatic circulation reabsorbs bile salts in the distal portion of the small intestine (ileum). All of the following statements about the enterohepatic circulation are true except one. Select the statement below that is not true of the enterohepatic circulation?
A
all of the components of bile are recycled in this circulation
22
Q
Which of the following is the best illustration of the difference between metabolism and digestion?
A
Metabolism comprises all of the chemical reactions preformed with in the body while digestion is only the breakdown of food within the G.I. Tract.
23
Q
Which of the following is least involved in the mechanical breakdown of food, digestion or absorption of nutrients?
A
esophagus
24
Q
Which of the following is the best explanation of the benefit in the digestive system having the largest collection of lymphoid tissue (MALT) at the distal end of the small intestine?
A
The huge numbers of bacteria living in the large intestine must be prevented from entering the lumen of the small intestine and being absorbed with food’s nutrients into the blood stream.
25
Which of the following would likely be absorbed in the stomach?
a serving of alcohol
26
Bile salts break up the fat globule into smaller fat droplets. This role of bile salts is best described as ________.
lipid emulsification
27
A doctor consulting a patient that recently has had their gallbladder removed would most likely advise ______.
eating foods that are low in fat
28
A ruptured appendix is life threatening because _________.
it is likely to cause massive infection of the abdominopelvic cavity
29
All but one of the following is a function of the low pH found in the stomach. Select the description below that does NOT reflect a role of stomach acid.
The stomach's acid catabolically breaks down food stuffs in preparation for absorption.
30
Fat absorption through the plasma membrane of epithelial cells _______.
occurs by simple diffusion because lipids are able to penetrate the hydrophobic fatty acid tails within the plasma membrane
31
Select the best explanation for why protease enzymes are secreted in inactive forms
The cells producing inactive enzymes are themselves protected from enzymes until they are safely within the lumen of the GI tract
32
Select the description below that illustrates a difference between a sphincter and circular muscle.
A sphincter is a thickening of circular muscle that can prevent the movement of digesting materials while circular muscle is involved in propulsion digesting material.
33
In the enteric nervous system, a long reflexive pathway has an advantage over a short reflexive pathway in the fact that ________.
long reflexive pathways can be stimulated by things outside of the GI tract
34
The sight of food can trigger a series of events that results in the release of gastric juice. All but one of the following is true in regards to the previous statement. Select the one answer that is not true.
The motor nerves of this pathway are part of the sympathetic division of the autonomic nervous system.
35
All of the following are true of swallowing (deglutition) except one. Select the statement that is not true of swallowing.
The epiglottis assists in propelling food into the trachea.
36
Some antacid drugs block histamine receptors, resulting in reduction of the production and excretion of stomach acid. These drugs have the biggest effect on which of the following?
parietal cells
37
All of the following are true of swallowing except one. Select the statement that is not true of swallowing.
the epiglottis assists in propelling food into trachea.
38
Which of the following is NOT a function of CCK?
increase production of stomach acid
39
Generally the hormones secretin and cholecystokinin which are released by duodenal enteroendocrine cells will ________.
slow the activities of the stomach
40
Select the one response below that would not result from a drug that blocks histamine receptors in the cells lining the stomach.
It would cause the release of secretin and cholecystokinin.
41
Specific enteroendocrine cells of the stomach, called G cells, are stimulated by partially digested proteins, caffeine, and rising pH. When stimulated, G cells secrete ______.
hydrochloric acid
42
The mechanical and chemical receptors that control digestive activity are located ________.
in the walls of the tract organs
43
The function of the hepatic portal circulation is to ________.
collect absorbed nutrients for metabolic processing in the liver
44
The chemical and mechanical processes of food breakdown are called ________.
digestion
45
When we ingest large molecules such as lipids, carbohydrates, and proteins, they must undergo catabolic reactions whereby enzymes split these molecules. This series of reactions is called ________.
chemical digestion
46
The sheets of peritoneal membrane that hold the digestive tract in place are called ________.
mesenteries
47
From the esophagus to the anal canal, the walls of every organ of the alimentary canal are made up of the same four basic layers. Arrange them in order from the lumen.
mucosa, submucosa, muscularis externa, and serosa
48
Which of the following is not a factor that helps create the stomach mucosal barrier?
secretion of pepsinogen
49
What part of the tooth bears the force and resists the friction of chewing?
enamel
50
The capillaries that nourish the epithelium and absorb digested nutrients lie in the ________.
lamina propria
51
Choose the incorrect statement regarding bile
Bile contains enzymes for digestion.
52
The absorptive effectiveness of the small intestine is enhanced by increasing the surface area of the mucosal lining. Which of the following accomplish this task?
villi, and microvilli
53
Select the statement that is true concerning primary teeth.
There are 20 primary teeth, and by 24 months of age most children have all 20.
54
Which of the following is true concerning the number and type of permanent teeth?
There are 32 permanent teeth, and the wisdom teeth are the last to emerge.
55
Which of the following is not true of saliva?
contains acids which aid in chemical digestion
56
Which of the following is not found in saliva?
protease
57
The bolus is liquefied in the ________ and it is now called chyme.
stomach
58
Peristaltic waves are ________.
waves of muscular contractions that propel contents from one point to another
59
Pepsinogen, an inactive digestive enzyme, is secreted by the ________.
chief cells of the stomach
60
You have just eaten a meal high in complex carbohydrates. Which of the following enzymes will help to digest the meal?
amylase
61
The ducts that deliver bile and pancreatic juice from the liver and pancreas, respectively, unite to form the ________.
hepatopancreatic ampulla
62
Short-chain triglycerides found in foods such as butterfat molecules in milk are split by a specific enzyme in preparation for absorption. Which of the following enzymes is responsible?
lipase
63
Hepatocytes do not ________.
produce digestive enzymes
64
Which vitamin requires intrinsic factor in order to be absorbed?
B12
65
Gastric pits, as opposed to gastric glands, are completely lined with ______.
mucous cells
66
Chemical digestion reduces large complex molecules to simpler compounds by the process of ________.
catabolism
67
The ________ contains lobules with sinusoids (lined with macrophages) that lead to a central venous structure
liver
68
Digestion and absorption of which of the following would be affected the most if the liver were severely damaged?
lipids
69
The dental formula for an adult is 2-1-2-3. What does the 1 stand for
canine tooth
70
The lamina propria is composed of ________.
loose connective tissue
71
Which of the following is (are) not important as a stimulus in the gastric phase of gastric secretion?
carbohydrates
72
The function of goblet cells is to ________.
produce mucus that protects parts of the digestive organs from the effects of powerful enzymes needed for food digestion
73
Which of the following is an essential role played by large intestine bacteria?
fermentation of indigestible carbohydrates
74
Nervous control of gastric secretion is provided by ________.
the vagus nerve and enteric plexus
75
Which of the following are types of papillae on the tongue that contain taste buds?
fungiform and circumvallate
76
Which of the following produce intrinsic factor?
parietal cells
77
Which of the following enzymes would be most active in the presents of a high concentrations of protein fragments?
trypsin
78
A child with restricted tongue movement may have a surgery that involves the cutting of the ________.
lingual frenulum
79
Which of the following is not characteristic of the large intestine?
is longer than the small intestine
80
What stomach secretion is necessary for normal hemoglobin production in RBCs?
intrinsic factor
81
Select the correct statement about the regulation of gastric secretion.
Gastric secretion can be stimulated before food has entered the mouth.
82
Paneth cells ________.
secrete enzymes that kill bacteria
83
Select the correct statement about absorption
In the rare case that intact, whole proteins are transported across the mucosal endothelium, an immune response may be generated
84
Which is not true of lipid absorption?
enterocytes require the presence of lipoprotein lipase to effectively absorb micelles.
85
The ingestion of a meal high in fat content would cause which of the following to occur?
Bile would be released from the gallbladder to emulsify the fat in the duodenum.
86
Hormones or paracrines that inhibit gastric secretion include ________.
secretin
87
Which of these is not part of the splanchnic circulation?
inferior vena cava
88
Which of these is not a component of saliva?
a cyanide derivative
89
The longest portion of the small intestine is the ________.
ileum
90
Cells of the stomach that secrete HCl are ________ cells
parietal
91
The chief bile pigment is ________.
bilirubin
92
Cells are found in the sinusoids of the liver that remove debris from the blood as it flows past are called ________ macrophages
stellate
93
The part of the peritoneum that covers the external surfaces of most digestive organs is the ________ peritoneum.
visceral
94
The ________ ligament anchors a tooth in the alveolus of the jaw
periodontal
95
The ________ phase of gastric secretions occurs when food enters the stomach.
gastric
96
The protective outermost layer of the esophagus is the ________.
adventitia
97
Compare and contrast the structure and function of a premolar and a molar
Premolars have a broad crown with rounded cusps but have only one root except the first upper molars that often have two. Molars also have broad crowns with rounded cusps but are larger than premolars. Molars have at least two roots.
98
What are chylomicrons?
Chylomicrons are tiny fatty droplets composed of triglycerides, small amounts of phospholipids, cholesterol, free fatty acids, and some protein that circulate in the blood but have not yet been reprocessed by the liver.
99
What is heartburn and what causes it?
Heartburn is the discomfort felt in the chest area when the acidic gastric juices get regurgitated into the esophagus. This may happen when someone has eaten or drunk too much, or it can be caused by extreme obesity or the discomfort of pregnancy. It is related to weakness of the gastroesophageal sphincter, frequently associated with hiatal hernia.
100
Name two regions of the digestive tract where mechanical food breakdown processes are very important. Name two organs that are primarily food conduits. Name the organ where protein digestion is begun. Name the organ where fat digestion begins.
Mechanical food processes are very important in the mouth (mastication) and stomach (contractions causing mixing of food into chyme). The esophagus and pharynx are primarily food conduits. Protein digestion begins in the stomach. Fat digestion begins in the small intestine.
101
Define constipation and diarrhea. Note possible causes of each.
Watery stools are called diarrhea. Constipation is a condition in which too much water has been absorbed and the stool becomes hard and difficult to pass. Any condition (such as irritation of the colon by bacteria) that rushes food residue through the large intestine before that organ has had sufficient time to absorb the remaining water results in diarrhea. Constipation may ensue from the lack of fiber in the diet, improper bowel habits, laxative abuse, or anything that decreases motility.
102
Assume you have been chewing a piece of bread for 5 or 6 minutes. How would you expect its molecular chemistry to change during this time? Why?
The bread will begin to change as some of the starch is broken down into the sugar maltose due to the chemical digestion of carbohydrates by salivary amylase.
103
Your friend suffers from heartburn and was told that he should "stop drinking caffeinated coffee because it is acidic." Explain to your friend why this is good advice but explain the mistaken facts to him.
Coffee's pH does not cause heartburn. However, caffeine can promote the release of gastrin hormone from G-cells in the stomach. Release of gastrin will result in the greater production of stomach acid that could worsen the pain of heartburn.
104
Why is it necessary for the stomach contents to be so acidic? How does the stomach protect itself from digestion?
HCl is necessary for the activation and optimal activity of pepsin, and it kills many of the bacteria ingested with food. Mucous cells in the lining of the stomach secrete an alkaline mucus that clings to the stomach wall and helps to shield it from the acid. The epithelial cells of the mucosa are joined together by tight junctions that prevent gastric juice from leaking into underlying tissue layers. Damaged epithelial cells are shed and quickly replaced by cell division.
105
Identify three ways the small intestine is modified to increase the surface area for digestion and absorption.
The plicae circulares, villi, and microvilli are modifications of the small intestine for digestion and absorption. The plicae circulares are circular folds of the mucosa and submucosa. They force chyme to move spirally through the lumen. The villi are fingerlike projections of the mucosa. They increase the absorptive surface area. Microvilli are projections of the plasma membrane of the absorptive cells of the mucosa that bear intestinal digestive enzymes. They also increase surface area and enhance absorption.
106
How is digestive activity provoked after eating? What activates the secretion of digestive juices into the lumen or hormones into the blood?
Mechanoreceptors located in the walls of the gastrointestinal tract respond to stretching by the introduction of food into the lumen. Likewise, chemoreceptors in the walls are able to respond to changes in solute concentration and pH as well as the presence of substrates and end products of digestion.
107
How is salivation regulated?
When we ingest food, chemoreceptors and pressoreceptors in the mouth send signals to the salivatory nuclei in the brain stem. The parasympathetic nervous system activity increases and motor fibers trigger the increase in serous, enzyme-rich saliva.
108
What is bile and where is it produced? What is its digestive function? Where is it stored and concentrated?
Bile is an alkaline solution containing bile salts, bile pigments, cholesterol, neutral fats, phospholipids, and a variety of electrolytes. It is produced in the liver. Its digestive function is to emulsify fats. It is stored and concentrated in the gallbladder.
109
Mrs. Wong goes to the emergency room with the following symptoms: severe pain in the umbilical region, loss of appetite, nausea, and vomiting. While she was waiting to see a doctor, the pain moved to the lower right abdominal quadrant. What is the likely diagnosis and treatment?
The most likely diagnosis is appendicitis. The accepted treatment is immediate surgical removal of the appendix.
110
Jose is brought to the emergency room complaining of a burning sensation in his chest, increased salivation, and difficulty in swallowing. He is having difficulty breathing and feels the presence of a "lump in his throat." The diagnosis is gastroesophageal reflux disease. Explain.
Gastroesophageal reflux disease is a disorder in which the rate of reflux is greater than in normal individuals and causes clinical symptoms and/or histological changes. Reflux and regurgitation may result in aspiration of gastric contents into the air passages, causing respiratory distress such as hoarseness, asthma, and pneumonia. The sensation of a lump in his throat may be due to esophageal muscle spasm from irritation or even worse, that he has developed a stricture (narrowing) or cancer from prolonged neglect.
111
Sami has been hospitalized with acute gastritis. Her symptoms were epigastric pressure (just above the stomach), headache, nausea, and vomiting with traces of old dark blood. She revealed that she had been suffering back pain and drank four shots of gin and took three aspirin to "kill the pain." What led the physician to make this diagnosis, and what may have caused the sudden attack?
Gastritis is an inflammation of the mucosal lining of the stomach and is suspected because of the pain location, accompanying symptoms, and ingestin of likely causative agents. He would likely confirm the diagnosis by doing an upper GI endoscopy. The probable reason for the abrupt onset of symptoms is due to rapid and heavy ingestion of alcohol and aspirin. Acute gastritis is often due to chemical irritants that destroy the alkaline mucus barrier, particularly alcohol or salicylate.
112
A woman is brought to an emergency room complaining of severe pain in her left iliac region. She claims previous episodes and says that the condition is worse when she is constipated, and is relieved by defecation. A large, tender mass is palpated in the left iliac fossa and a barium study reveals a large number of diverticula in her descending and sigmoid colon. What are diverticula, and what is believed to promote their formation? Does this woman have diverticulitis or diverticulosis? Explain.
Diverticula are small herniations of the mucosa through the colon walls, a condition called diverticulosis. They are believed to form when the diet lacks bulk and the volume of residue in the colon is small. The colon narrows contractions of its circular muscles and they become more powerful, increasing the pressure on its walls. Diverticulitis is a condition in which the diverticula become inflamed. This woman has diverticulitis due to the inflammation of her diverticula, as evidenced by the pain and mass.
113
A patient is 67 years old and has had a hiatal hernia for three years. In the last year, she has complained of worsening heartburn, especially at night. What are the characteristic symptoms of a hiatal hernia and which of these symptoms did the patient have?
Heartburn and regurgitation from gastroesophageal reflux are the most common clinical manifestations of hiatal hernia. This patient complained of heartburn.
114
A patient was admitted to the hospital because of severe epigastric pain. He has noted that his stools were darker than the usual brown color. He appears pale and very anxious. The history reports that he drinks 2-3 beers per day and smokes 2 packs of cigarettes a day. Based on the assessment data, what condition might the nurse determine this patient has? Explain why.
The patient most likely has a gastric ulcer. The most distressing symptom of a gastric ulcer is gnawing epigastric pain that seems to bore through to the back. The danger posed by ulcers is perforation of the stomach wall followed by peritonitis and massive hemorrhage. Because the patient's stools are darker than usual and he is pale and anxious, the nurse suspects a bleeding ulcer. Factors such as smoking and alcohol increase hypersecretion of hydrochloric acid and low secretion of mucus.
115
A patient has esophageal cancer and must have a feeding tube inserted. The nurse tells the patient that the tube will be inserted surgically into the duodenum. The patient's wife asks why the tube will not be inserted into the stomach. What should the nurse say?
The duodenum is part of the small intestine, which is the body's major digestive organ. Digestion is completed and absorption is best in the small intestine. There is also less risk for vomiting, which may cause complications.
116
A 45-year-old patient was admitted to the hospital with a diagnosis of cirrhosis of the liver. He is thin and malnourished. His abdomen is very large due to an accumulation of fluid in the abdominal cavity. His lower extremities are very swollen. Explain why these changes have occurred.
Cirrhosis is a diffuse and progressive chronic scarring of the liver that typically results from chronic alcoholism or severe chronic hepatitis. Cirrhosis is characterized by extensive degeneration and destruction of the liver parenchymal cells. Edema and ascites (accumulation of fluid in the peritoneal cavity) Occur because the portal blood cannot flow as easily through narrowed, scarred canaliculi, leading to a backup of pressure (portal hypertension) that causes increased filtration loss of fluid through intestinal capillary walls.
117
A 45-year-old patient was admitted to the hospital with a diagnosis of cirrhosis of the liver. The nurse is observing him closely for the possibility of gastrointestinal bleeding. Why is this considered a possible complication?
As scar tissue eventually shrinks, it obstructs blood flow throughout the hepatic portal system, causing portal hypertension. Some veins of the portal system anastomose with veins that drain into the venae cavae. However, these connecting veins are small, include submucosal veins in the lower esophagus and gastric cardia, and tend to burst when forced to carry large volumes of blood. Signs of their failure include vomiting blood.
