The peritoneal cavity
A)Is the same thing as the abdominopelvic cavity
B)Is filled with air
C)Like the pleural and pericardial cavities is a potential space containing serous fluid.
D)Contains the pancreas and all of the duodenum
Obstruction of the hepatopancreatic sphincter impairs digestion by reducing the availability of
A)Bile and HCI
B)HCI and intestinal juice
C)Pancreatic Juice and intestinal juice
D)Pancreatic Juice and Bile
The action of an enzyme is influenced by
A)Its chemical surroundings
C)The presence of needed cofactors of coenzymes
D)All of these
Carbohydrates are acted on by
A)Peptidases, trypsin, and chymotrypsin
B)Amylase, maltase, and sucrose
D)Peptidases, lipases and galactase
The Parasympathetic nervous system influences digestion by
A)Relaxing smoot muscle
B)Stimulating peristalsis and secretory activity
D)None of these
the digestive juice product, containing enzymes capable of digesting all four major foodstuff categories is
Someone who has eaten a meal of buttered toast, cream, and eggs, which of the following would you expect to happen?
A)Compared to the period shortly after the meal, gastric motility and secretion of HCI decrease when food reaches the duodenum
B)gastric motility increases even as the person is chewing the food (before swallowing)
C)fat will be emulsified in the duodenum by the action of bile
D)all of these
The site of production of VIP and cholectystokinin is
B)The small intestine
D)The large intestine
Which of the following is not characteristic of the colon?
A)It is divided into ascending, transverse, and descending portions
B)It contains abundant bacteria, some of which is synthesize certain vitamins
C)It is the main absorptive site
D)It absorbs much of the water and salts remaining in the wastes
The gall bladder
B)Is attached to the pancreas
C)Stores and concentrates bile
The sphincter between the stomach and duodenum is
A)The pyloric sphincter
B)The gastroesophageal sphincter
C)The hepatopancreatic sphincter
D)The ileocecal sphincter
The protein molecule will be digested by enzymes made by
A)The mouth, stomach and colon
B)The stomach, liver and small intestine
C)The small intestine, mouth and liver
D)The pancreas, stomach and small intestine
The protein molecule must be digested before it can be transported to and utilized by the cells because
A)Protein is only useful directly
B)Protein has a low pH
C)Proteins in the circulating blood produce an adverse osmotic pressure
D)The protein is too large to be readily absorbed
The products of protein digestion enter the bloodstream largely through the cells lining
B)The small intestine
C)The large intestine
D)The bile duct
Before the blood carrying the products of protein digestion reaches the heart it first passes through capillary networks in
Having passed through the regulatory organ selected above, the products of protein digestion are circulated through out the body. They will enter individual budy cells by
make a simple line drawing of the organs of the alimentary canal and label each organ. Then add three labels to your drawing – salivary glands, liver, and pancreas – use arrow to show where each of these organs empties its secretions into the alimentary canal
Sara was on a diet but she could not eat less and kept claiming her stomach had a mind of its own. She was joking, but indeed, there is a "gut brain" called the enteric nervous system. It is part of the parasympathetic and sympathetic nervous system? Explain.
The digestive system does contain local nerve plexuses known as the local (enteric) nervous system or the gut brain. This is essentially composed of nerve plexuses in the wall of the alimentary canal that extend the entire length of the GI tract. These plexuses respond to local stimuli in the GI tract by initiating both short and long reflexes. The gut brain solely mediates the short reflexes. Long reflexes are initiated by both external and local stimuli, and involve both the gut brain and the ANS. (Sympathetic nerves inhibit GI tract activity, whereas parasympathetic nerves, primarily the vagus nerve, stimulate it.) (pp. 857-858)
Name the layers of the alimentary canal wall. Note the tissue composition and the major function of both
The basic alimentary canal wall structure consists of four tunics: the mucosa, submucosa, muscularis, and serosa.
•Mucosa consists of a surface epithelium underlain by a small amount of connective tissue called the lamina propria and a scanty amount of smooth muscle fibers, the muscularis mucosae. Typically, the epithelium of the mucosa is a simple columnar epithelium rich in mucus-secreting goblet cells and other types of glands. The mucus protects certain digestive organs from being digested themselves by the enzymes working within their cavities and eases the passage of food along the tract. In some digestive organs the mucosa contains both enzyme-secreting and hormone-secreting cells. The lamina propria, consisting of areolar connective tissue and containing lymph nodules, is important in the defense against bacteria and other pathogens. In the small intestine, the muscularis mucosae throw the mucosal tunic into a series of small folds that vastly increases its surface area for secretion and absorption.
•Submucosa is areolar connective tissue containing blood vessels, lymphatic vessels, nerve endings, and epithelial glands. Its vascular network supplies surrounding tissues and carries away absorbed nutrients. Its nerve plexus is part of the enteric nerve supply of the gastrointestinal tube.
•Muscularis externa mixes and propels food along the digestive tract. This muscular tunic usually has an inner circular layer and an outer longitudinal layer of smooth muscle cells, although there are variations in this pattern.
•Serosa is formed of areolar connective tissue covered with mesothelium, a single layer of squamous epithelial cells. It is the protective outermost layer and the visceral peritoneum. (pp. 856–857)
What is mesentery? Mesocolon? Greater omentum?
The mesentery is a double peritoneal fold that suspends the small intestine from the posterior abdominal wall. The mesocolon is a special dorsal mesentery that secures the transverse colon to the parietal peritoneum of the posterior abdominal wall. The greater omentum is also a double peritoneal sheet that covers the coils of the small intestine and wraps the transverse portion of the large intestine. (pp. 855, 890, 868)
Name the six functional activities of the digestive system.
A) describe the boundaries of the oral cavity.
B) Why do you suppose its mucosa is stratified squamous epithelium rather than the more typical simple columnar epithelium?
A) What is the normal number or permanent teeth? Of deciduous teeth?
B)What substance covers the tooth crown? Its root?
C) What substance makes up the bulk of a tooth?
D) What and where is pulp?
a)The normal number of permanent teeth is 32; deciduous teeth, 20.
b)Enamel covers the crown; cementum, the root.
c)Dentin makes up the bulk of the tooth.
d)Pulp is found in the central cavity in the tooth. Soft tissue structures (connective tissue, blood vessels, and nerve fibers) compose pulp. (pp. 862-863)
Describe the two phases of swallowing, noting the organs involved and the activities that occur.
The two phases of swallowing are as follows:
• Buccal (voluntary) phase of swallowing: organs involved—tongue, soft palate; activities—tongue compacts food into a bolus, forces the bolus into the oropharynx via tongue contractions. The soft palate rises to close off the superior nasopharynx. (p. 866)
• Pharyngeal-esophageal (involuntary) phase: organs involved—pharynx and esophagus; activities—motor impulses sent from the swallowing center to their muscles, which contract to send the food to the esophagus by peristalsis. Arrival of food/peristaltic wave at the gastroesophageal sphincter causes it to open. (p. 866)
Describe the role of these cells found in gastric glands: parietal, chief, mucous neck, and enteroendocrine.
Describe the regulation of the cephalic, gastric, and intestinal phases of gastric secretion.
•Gastric secretion is controlled by both neural and hormonal mechanisms. The stimulation of gastric secretion involves three distinct phases: the cephalic, gastric, and intestinal phases.
•Cephalic phase -occurs before food enters the stomach and is triggered by the sight, aroma, taste, or thought of food. Input is relayed to the hypothalamus, which stimulates the vagal nuclei of the medulla oblongata, causing motor impulses to be sent via vagal nerve fibers to the stomach. This reflex may be dampened during depression or loss of appetite.
•Gastric phase is initiated by neural and hormonal mechanisms once food reaches the stomach. Stomach distension activates stretch receptors and initiates reflexes that transmit impulses to the medulla and then back to the stomach, leading to acetylcholine release. Acetylcholine stimulates the output of gastric juice. During this phase, the hormone gastrin is more important in gastric juice secretion than neural influences. Chemical stimuli provided by foods directly activate gastrin-secreting cells. Gastrin stimulates the gastric glands to spew out even more gastric juice. Gastrin secretions are inhibited by high acidity.
•Intestinal phase is set into motion when partially digested food begins to fill the duodenum. This filling stimulates intestinal mucosal cells to release a hormone (intestinal gastrin) that encourages the gastric glands to continue their secretory activity briefly; but as more food enters the small intestine, the enterogastric reflex is initiated, which inhibits gastric secretion and food entry into the duodenum to prevent the small intestine from being overwhelmed. Additionally, intestinal hormones (enterogastrones) inhibit gastric activity. (pp. 872-873)
A) What is the relationship between the cystic, common hepatic, bile, and pancreatic ducts?
B) What is the point of fusion of the bile and pancreatic ducts called?
Explain why fatty stools result from the absence of bile or pancreatic juice.
Indicate the function of the stellate macrophages and the hepatocytes of the liver
What are (a) brush border emzyems? (b) chylomicrons
a. Brush border enzymes are intestinal digestive enzymes; these are part of the plasma membrane of the microvilli of the intestinal absorptive cells. (p. 878)
b. Chylomicrons are fatty droplets consisting of triglycerides combined with small amounts of phospholipids, cholesterol, and free fatty acids, and coated with proteins. They are formed within the absorptive cells and enter the lacteals. (p. 900)
Activation of pancreatic enzymes in the small intestine is a good example of the wisdom of the body. How so?
Name one inflammatory condition of the digestive system particularly common to adolescents, two common in middle age, and one common in old age.
What are the effects of aging on digestive system activities?
You are a young research assistant at a pharmaceutical company. Your group has been asked to develop an effective laxative that
(1) provides bulk and
(2) is nonirritating too the intestinal mucosa.
Explain why these requests are important by describing what would happen if the opposite conditions were presented.
If the agent promotes increased bowel motility without providing for increased bulk, diverticulosis is a possibility, because the rigor of the colonic contractions increases when the volume of residues is small. This increases the pressure on the colon wall, promoting the formation of diverticula. If the product irritates the intestinal mucosa, diarrhea will occur. Intestinal contents will be moved rapidly through both the small and large intestines, leaving inadequate time for absorption of water, which can result in dehydration and electrolyte imbalance. (pp. 893–895)
After a heavy meal rich with fried foods, Debby Collins, an over-weight 45 year-old-woman, was rushed to the emergency room with severe spasmodic pains in her epigastric region that radiated to the right side of her rib cage. She indicated that the attack came on suddenly, and her abdomen was found to be tender to the touch and somewhat rigid. What do you think is the patient's problem and why is her pain discontinuous (colicky)? What are the treatment options and what might happen if the problem is not resolved?
This patient has the classical symptoms of a gallbladder attack in which a gallstone has lodged in the cystic duct. The pain is discontinuous and colicky because it reflects the rhythm of peristaltic contractions (contract-relax-contract-relax, etc.). The stone can be removed surgically or by sound or laser treatment. If it is not removed, bile will back up into the liver, and jaundice will result. (p. 885)
A baby is admitted to the hospital with a history of diarrhea and watery feces occurring over the last three days. The baby has sunken fontanels, indicating extreme dehydration. Tests indicate that the baby has a bacterium-induced colitis, and antibiotics are prescribed. Because of the baby's loss of intestinal juices, do you think that the blood ph would indicate an acidosis or an alkalosis? Explain your reasoning.
Gary Francis, a middle-aged salesman, complains of burning pain in the “pit of his stomach,” usually beginning about two hours after eating and abating after drinking a glass of milk. When asked to indicate the site, he points to his epigastric region. The GI tract is examined by X-ray fluoroscopy. A gastric ulcer is visualized, and drug therapy using an antibiotic-bismuth approach is recommended.
(a) Why is this treatment suggested?
(b) What are the possible consequences of no treatment?
a.Most gastric ulcers are found to be caused by infection with Helicobacter pylori. This drug regimen successfully eradicates the infection.
b.Possible consequences of nontreatment could be surgical removal of the existing ulcer due to internal bleeding, or the occurrence of multiple ulcers. (pp. 870–871)
Dr. Dolan used an endoscope to view Mr. Habib's colon. He noted the presence of several polyps and removed them during the same procedure. What is an endoscope? Why did Dr. Dolan opt to remove the polyps immediately?
An endoscope is an instrument used to visually inspect any cavity of the body and is composed of an illuminated fiber optic tube with a lens. The polyps seen were removed immediately because most colorectal cancers arise from initially benign polyps. Presently, colon cancer is the second largest cause of cancer death in males in the U.S. (p. 908)
Mr. Holden has had severe diarrhea all day and is severely weakened. Explain why his nurse is concerned about his present condition.
What is the protective value of having several sets of tonsils at the oral enterance to the pharynx?
The circle of tonsils around the opening of the pharynx is protective because the tonsils serve to invite pathogens in and expose the body defense system to them so a person can build immunity. What better location for such a function than right in the opening of the passageway for food, liquids, and air? (p. 760)