Ch23/01

Which vitamin requires intrinsic factor in order to be absorbed?

B12

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.

Pepsinogen is the precursor to the gastric enzyme for protein digestion and is secreted by the parietal cells.

False

The relatively unchanging pressure in a filling stomach is due to the contraction of the stomach oblique muscle layer.

False

Chief cells secrete inactive pepsinogen in order to prevent acid erosion inside of the chief cells.

False Explanation: Chief cells do secrete pepsinogen, but the result is unrelated to acidity. When pepsinogen is activated by HCl secreted by the parietal cells, it is converted into pepsin, which is an enzyme that acts on proteins.

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.

Which of the following processes occurs in the stomach?

Mechanical digestion. It occurs in the stomach by churning.

Which of the following is the best illustration of the difference between metabolism and digestion?

Metabolism comprises all of the chemical reactions preformed with in the body while digestion is only the breakdown of food within the GI tract.

Proteins entering the stomach act as a buffer raising pH. Rising pH stimulates the activity of G-cells in the lining of the stomach. All of the following but one will occur. Select the statement below that would not occur.

A positive feedback response will be initiated and G-cell activity will continue to go up.

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.

Which of the following is (are) not important as a stimulus in the gastric phase of gastric secretion?

carbohydrates

Chemical digestion reduces large complex molecules to simpler compounds by the process of ________.

catabolism

Pepsinogen, an inactive digestive enzyme, is secreted by the ________.

chief cells of the stomach

The function of the hepatic portal circulation is to ________.

collect absorbed nutrients for metabolic processing in the liver

Which of the following does NOT describe a basic regulator of digestive control?

conscious neural control Explanation: Neural control over the digestive system is through the autonomic nervous system, which does not function under conscious control mechanisms.

The chemical processes of food breakdown are called ________.

digestion

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 ________.

digestion

Which of the following is least involved in the mechanical breakdown of food, digestion or absorption of nutrients?

esophagus

Most gastric ulcers are due to excessive production of hydrochloric acid.

false

The intestinal phase of stomach digestion is triggered by partially digested nutrients filling the pylorus.

false

The only essential function of the stomach is to begin the digestion of proteins.

false

The pharyngeal-esophageal phase of swallowing is involuntary and is controlled by the swallowing center in the thalamus and lower pons.

false

The soft palate reflexively opens the nasopharynx to allow the passage of food, which is now called a bolus.

false

The stomach's contractile rhythm is set by pacemaker cells found in the spinal cord.

false

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

Which of the following produce intrinsic factor?

parietal cells

What control mechanism opens the gastroesophageal sphincter?

peristalsis in the esophagus Explanation: As the peristaltic wave triggered by deglutition reaches the stomach, the gastroesophageal sphincter relaxes and allows food into the stomach.

Chief cells ________.

produce pepsinogen

What role of the stomach is essential to life?

production of intrinsic factor Explanation: Without the production of intrinsic factor, the body would not be able to absorb vitamin B12 in the small intestine. This is the only factor that would cause problems with living.

Which of the following functions is NOT correctly matched with its description?

propulsion: physical breakdown of ingested food in the GI tract Explanation: Propulsion is the movement of ingested food through the GI tract.

Gastric juice does not typically cause a burning sensation within the stomach. But reflux of this gastric juice into the esophagus can cause a burning sensation. One reason why this occurs is that the esophagus ______.

secretes mucus that is not identical to stomach mucus Explanation: The function of the mucus-producing esophageal glands is to lubricate the food bolus as it travels toward the stomach.

Hormones or paracrines that inhibit gastric secretion include ________.

secretin

Which of the following is not a factor that helps create the stomach mucosal barrier?

secretion of pepsinogen

The outermost tissue layer of the alimentary canal is the __________.

serosa

Generally the hormones secretin and cholecystokinin which are released by duodenal enteroendocrine cells will ________.

slow the activities of the stomach

Which organ of the digestive tract is the body's major digestive organ?

small intestine Explanation: The small intestine is the major digestive organ because it is the site of the majority of enzymatic digestion and absorption of nutrients.

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.

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, and why?

The patient most likely has a bleeding gastric ulcer. The most distressing symptom of a gastric ulcer is gnawing epigastric pain that seems to bore through to the back. As his stools are darker than usual and he is pale and anxious, he probably has a bleeding ulcer.

Which of the following is NOT a characteristic of the stomach?

The stomach releases enzymes to digest carbohydrates.

All the chemical and mechanical phases of digestion and mechanical breakdown from the mouth through the small intestine are directed toward changing food into forms that can pass through the epithelial cells lining the mucosa into the underlying blood and lymphatic vessels.

True

Which of the following is NOT a means of mechanically breaking down food? a. segmentation b. peristalsis c. mastication d. churning

b. peristalsis Explanation: Peristalsis is a physical process used for propulsion, or movement, through the GI tract.

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. a. Stomach acid denatures proteins making the polypeptide chain more accessible to pepsin digestive enzymes. b. Low pH converts pepsinogen to its active form, pepsin. c. The stomach's acid catabolically breaks down foodstuffs in preparation for absorption. d. Many potentially harmful bacteria will be prevented entry to the small intestine by stomach acid.

c. The stomach's acid catabolically breaks down foodstuffs in preparation for absorption.

Peritoneal organs are completely covered in a serous membrane and have a dorsal and ventral mesentery.

false Explanation: Peritoneal organs are covered in a serous membrane, the peritoneum. However, many peritoneal organs only have a dorsal mesentery. A ventral mesentery is only evident on a few peritoneal organs.

Unitary smooth muscle is found in all hollow organs except for the heart. What structure do both heart muscle and unitary smooth muscle share that allows them to contract as a functional group?

gap junctions

Select the correct statement about the regulation of gastric secretion.

gastric secretion can be stimulated before food has entered the mouth.

The __________ circulation drains all of the organs of the digestive system.

hepatic portal Explanation: The hepatic portal circulation drains all of the blood from the digestive organs and routes that blood through the liver for processing.

The mechanical and chemical receptors that control digestive activity are located ________.

in the walls of the tract organs

Generally the hormones secretin and cholecystokinin which are released by duodenal enteroendocrine cells will ________.

increase the release of digestive enzymes and bile

Which of these is not part of the splanchnic circulation?

inferior vena cava

In the __________ phase of gastric secretion, chyme is moved into the duodenum.

intestinal Explanation: The intestinal phase occurs when chyme is moved into the duodenum.

What stomach secretion is needed to produce mature erythrocytes?

intrinsic factor

The capillaries that nourish the epithelium and absorb digested nutrients lie in the ________.

lamina propria

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

The lamina propria is composed of ________.

loose connective tissue

The sheets of peritoneal membrane that hold the digestive tract in place are called ________.

mesenteries

Which layer of the stomach contains the gastric pits that secrete mucous, acid, and digestive enzymes? (image of Gross anatomy of the stomach and arrangement of the basic layers of the stomach wall.)

mucosa Explanation: The mucosa of the stomach contains the epithelial lining and the gastric pits, which extend down into the mucosa but do not penetrate the submucosa.

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

In a patient suffering from a gastric ulcer caused by Helicobacter pylori, the cells most likely to have been damaged first are the ______.

mucous cells Explanation: The mucosal barrier protects the underlying stomach tissue from the harsh effects from acidic pH found in the lumen.

Which layer of the digestive tract controls digestive propulsion?

muscularis externa Explanation: The smooth muscles in the muscularis work to make the propulsive movements called peristalsis.

In a patient suffering from untreated infection-induced peritonitis, an infection in the visceral peritoneum immediately ______.

spreads directly to the parietal peritoneum Explanation: The parietal peritoneum lines the body wall and is separated from the visceral peritoneum by the fluid-filled peritoneal space.

The bolus is liquefied in the ________ and it is now called chyme.

stomach

Which layer of the alimentary canal contains not only glands and blood vessels but also a nerve plexus that helps regulate digestive activity? (image of Generalized histological structure and layering of the digestive tract.)

submucosa Explanation: The submucosa layer contains blood and lymphatic vessels, lymphoid follicles, and the submucosal plexus of nerve fibers.

Which of the organs listed below is involved in all of the following processes: secretion, mechanical breakdown of food, digestion and absorption?

the stomach

Nervous control of gastric secretion is provided by ________.

the vagus nerve and enteric plexus

Another term for swallowing is deglutition.

true

Fats significantly delay the emptying of the stomach through hormonal and neuronal signals.

true

Gastric accommodation is an example of smooth muscle plasticity.

true

Some of the microbes that often invade other organs of the body are rarely found in the stomach. The reason for this is the presence of HCl.

true

The intrinsic ability of visceral smooth muscle to exhibit the stress-relaxation response is termed plasticity.

true

The major means of propulsion through the alimentary canal is peristalsis.

true

The major stimulus for production of intestinal fluid is distention or irritation of the intestinal mucosa by hypertonic or acidic chyme.

true

The peritoneum is the most extensive serous membrane in the body.

true

When swallowing, the epiglottis covers the larynx.

true

The __________ is the serous membrane that lines the abdominal organs.

visceral peritoneum Explanation: The visceral peritoneum covers the external surface of most digestive organs.

Peristaltic waves are ________.

waves of muscular contractions that propel contents from one point to another