Bio 227 Chapter 23 Dynamic Study Modules
Question: What structure of the small intestine is known as the brush border?
Answer: Microvilli Description: Microvilli are also known as the brush border. Microvilli are long, densely packed cytoplasmic extentions of the absorptive cells of the mucosa that give the mucosal surface a fuzzy appearance called the brush border. The plasma membranes of the microvilli bear enzymes referred to as brush border enzymes, which complete the digestion of carbohydrates and proteins in the small intestine.
Question: When whole proteins are absorbed and seen by the immune system, this may lead to which of the following conditions?
Answer: Allergies Description: When whole proteins are absorbed and and seen by the immune system, this may lead to allergies. Whole proteins are not usually absorbed, but in rare cases intact proteins are taken up by endocytosis and released on the opposite side of the epithelial cell by exocytosis. This process is most common in newborn infants, reflecting the immaturity of their intestinal mucosa (gastric acid secretion does not reach normal levels until weeks after birth, and the mucosa is leakier than it is later.) Absorption of whole proteins accounts for many early food allergies: The immune system "sees" the intact proteins as antigenic and mounts an attack. These allergies usually disappear as the mucosa matures.
Question: Match the following substance involved in organic molecule digestion with its description: Salivary amylase
Answer: Begins carbohydrate digestion in the mouth Description: Salivary amylase begins carbohydrate digestion in the mouth. A number of glands associated with the oral cavity secrete saliva. Saliva: Cleanses the mouth Dissolves food chemicals so they can be tasted Moistens food and helps compact it into a bolus Contains the enzyme amylase that begins the digestion of starchy foods Pepsin is an enzyme that digests proteins in the stomach. Bile emulsifies fats for digestion in the small intestine. Brush border enzymes of the small intestine break olig- and disaccharides into monosaccharides.
Question: __________ is not found in pancreatic secretions.
Answer: Cholecystokinin (CCK) Description: Cholecystokinin (CCK) is not found in pancreatic secretions as it is a hormone. As shown in the table, cholecystokinin (CCK) is released by the duodenal mucosal and is not found in pancreatic secretions.
Question: The permanent dentition consists of __________ teeth in a full set.
Answer: 32 Description: The permanent dentition consists of 32 teeth in a full set. As the deep-lying permanent teeth enlarge and develop, the roots of the milk teeth are resorbed from below, causing them to loosen and fall out between ages 6 and 12. Generally, all the permanent teeth but the third molars have erupted by the end of adolescence. The third molars, also called wisdom teeth, emerge between ages 17 and 25. There are usually 32 permanent teeth in a full set, but sometimes the wisdom teeth never erupt or are completely absent. The dental formula is a shorthand way of indicating the numbers and relative positions of the different types of teeth. This formula is written as a ratio, uppers over lowers, for one-half of the mouth. Since the other side is a mirror image, we obtain total dentition by multiplying the dental formula by 2. The primary dentition consists of two incisors (I), one canine (C), and two molars (M) on each side of each jaw, and its dental formula is written as 2I, 1C, 2M (upper jaw) 2I, 1C, 2M (lower jaw) × 2 (20 teeth) Similarly, the permanent dentition [two incisors, one canine, two premolars (PM), and three molars] is 2I, 1C, 2PM, 3M 2I, 1C, 2PM, 3M × 2 (32 teeth)
Question: Which of the following is the most common cause of peritonitis?
Answer: A burst appendix Description: The most common cause of peritonitis is a burst appendix. Peritonitis is inflammation of the peritoneum. It can arise from a piercing abdominal wound, a perforating ulcer that leaks stomach juices into the peritoneal cavity, or poor sterile technique during abdominal surgery. However, most commonly it results from a burst appendix that sprays bacteria-containing feces all over the peritoneum. In peritonitis, the peritoneal coverings tend to stick together around the infection site. This localizes the infection, providing time for macrophages to prevent the inflammation from spreading. If peritonitis becomes widespread within the peritoneal cavity, it is dangerous and often lethal. Treatment includes removing as much infectious debris as possible and administering mega-doses of antibiotics.
Question: Match the following: IBD
Answer: A noncontagious, periodic inflammation of the intestinal wall now understood to be an abnormal immune and inflammatory response to bacterial antigens Description: Inflammatory bowel disease (IBD) is a noncontagious, periodic inflammation of the intestinal wall now understood to be an abnormal immune and inflammatory response to bacterial antigens that normally occur in the intestine. This disorder is linked to TH17 cells, certain cytokines, and the loss of a normal epithelial barrier. IBD afflicts up to two of every 1000 people. Symptoms include cramping, diarrhea, weight loss, and intestinal bleeding. Two subtypes occur: (1) Crohn's disease, a syndrome characterized by relapsing and remitting periods. Deep ulcers and fissures can develop anywhere along the GI tract, but mostly occur in the terminal ileum. (2) Ulcerative colitis is characterized by inflammation of the large-intestinal mucosa, mainly in the rectum. Both types are treated with anti-inflammatory and immunosuppressant drugs and sometimes probiotic agents and antibiotics. Extremely severe cases of ulcerative colitis are treated by colectomy (removal of a portion of the colon). Enteritis is an inflammation of the intestine, especially the small intestine. Excess iron deposited in the tissues is called hemochromatosis. When all GI tract movement stops and the gut appears to be paralyzed, this is called ileus. Pancreatitis may result from excessively high levels of fat in the blood or excessive alcohol ingestion, but most acute cases arise from gallstones that block the bile duct. Extreme dryness of the mouth is called xerostomia.
Question: Match the following: Ileus
Answer: All GI tract movement stops and the gut appears to be paralyzed Description: Ileus (il'e-us): A condition in which all GI tract movement stops and the gut appears to be paralyzed. Can result from electrolyte imbalances and blockade of parasympathetic impulses by drugs (such as those commonly used during abdominal surgery); usually reversed when these interferences end. The reappearance of intestinal sounds (gurgling, etc.) indicates restoration of motility. Enteritis is an inflammation of the intestine, especially the small intestine. Excess iron deposited in the tissues is called hemochromatosis. A noncontagious, periodic inflammation of the intestinal wall occurs in inflammatory bowel disease (IBD). Pancreatitis may result from excessively high levels of fat in the blood or excessive alcohol ingestion, but most acute cases arise from gallstones that block the bile duct. Extreme dryness of the mouth is called xerostomia.
Question: ________ and ___________ mix together at the hepatopancreatic ampulla.
Answer: Bile and pancreatic enzymes Description: Bile and pancreatic enzymes mix together at the hepatopancreatic ampulla. The bile duct, delivering bile from the liver, and the main pancreatic duct, carrying pancreatic juice from the pancreas, unite in the wall of the duodenum, the first section of the small intestine, in a bulblike structure called the hepatopancreatic ampulla (hep"ah-to-pan"kreat' ik am-pul'ah; ampulla = flask). The ampulla opens into the duodenum via the volcano-shaped major duodenal papilla. A smooth muscle valve called the hepatopancreatic sphincter controls the entry of bile and pancreatic juice. A smaller accessory pancreatic duct empties directly into the duodenum just proximal to the main duct.
Question: Select the description for the structure labeled 'A.'
Answer: Brittle and thick as a dime Description: "A" is the enamel, which is brittle and thick as a dime. Each tooth has two major regions: the crown and the root. The enamel-covered crown is the exposed part of the tooth above the gingiva (jin'jĭ-vah), or gum, which surrounds the tooth like a tight collar. Enamel, a brittle ceramic-like material thick as a dime, directly bears the force of chewing. The hardest substance in the body, it is heavily mineralized with calcium salts, and its densely packed hydroxyapatite (mineral) crystals are oriented in force-resisting columns perpendicular to the tooth's surface. The cells that produce enamel degenerate when the tooth erupts; consequently, decayed or cracked areas of enamel will not heal and must be artificially filled. The root is the portion of the tooth embedded in the jawbone. Canine teeth, incisors, and premolars have one root, although the first upper premolars commonly have two. The first two upper molars have three roots, while the corresponding lower molars have two. The root pattern of the third molar varies, but a fused single root is most common. A constricted tooth region called the neck connects the crown and root. Cement, a calcified connective tissue, covers the outer surface of the root and attaches the tooth to the thin periodontal ligament (per"e-o-don'tal; "around the tooth"). This ligament anchors the tooth in the bony socket (alveolus) of the jaw, forming a fibrous joint called a gomphosis. Where the gingiva borders on a tooth, it dips downward to form a shallow groove called the gingival sulcus. Dentin, a protein-rich bonelike material, underlies the enamel cap and forms the bulk of a tooth. More resilient than enamel, dentin acts as a shock absorber during biting and chewing. Dentin surrounds a central pulp cavity containing a number of soft tissue structures (connective tissue, blood vessels, and nerve fibers) collectively called pulp. Pulp supplies nutrients to the tooth tissues and provides tooth sensation. Where the pulp cavity extends into the root, it becomes the root canal.
Question: Select the phrase that describes sucrase, lactase and maltase.
Answer: Brush border enzymes that act on disaccharides Description: The brush border enzymes that act on disaccharides are sucrase, lactase, and maltase. Brush border enzymes break oligo- and disaccharides into monosaccharides. Intestinal brush border enzymes further digest these products to monosaccharides. The most important brush border enzymes are dextrinase and glucoamylase, which act on oligosaccharides composed of more than three simple sugars, and maltase, sucrase, and lactase, which hydrolyze maltose, sucrose, and lactose respectively into their constituent monosaccharides. Because the intestine can absorb only monosaccharides, all dietary carbohydrates must be digested to monosaccharides to be absorbed.
Question: Which phase of swallowing is voluntary?
Answer: Buccal phase Description: The buccal phase of swallowing is the only voluntary phase of swallowing. To send food on its way from the mouth, it is first compacted by the tongue into a bolus and is then swallowed. This complicated process involves the coordinated activity of over 22 separate muscle groups. There are two major phases involved in deglutition, or swallowing. The buccal phase occurs in the mouth and is voluntary. It ends when a food bolus or a "bit of saliva" leaves the mouth and stimulates tactile receptors in the posterior pharynx, initiating the next phase. The pharyngeal-esophageal phase is involuntary and is controlled by the swallowing center in the brain stem (medulla and lower pons). Various cranial nerves, most importantly the vagus nerves, transmit motor impulses from the swallowing center to the muscles of the pharynx and esophagus. Once food enters the pharynx, respiration is momentarily inhibited and all routes except the desired one into the digestive tract are blocked off. Solid foods pass from the oropharynx to the stomach in about 8 seconds, and fluids, aided by gravity, pass in 1 to 2 seconds.
Question: Match the following: GERD
Answer: Causes a burning radiating substernal pain due to regurgitation of stomach acid into the esophagus. Description: GERD causes a burning radiating substernal pain due to regurgitation of stomach acid into the esophagus. Heartburn, the first symptom of gastroesophageal reflux disease (GERD), is the burning, radiating substernal pain that occurs when stomach acid regurgitates into the esophagus. Symptoms are so similar to those of a heart attack that many first-time sufferers of heartburn are rushed to the emergency room. Heartburn is most likely when a person has eaten or drunk to excess, and in conditions that force abdominal contents superiorly, such as extreme obesity, pregnancy, and running, which splashes stomach contents upward with each step. In 25% of mumps cases in adult males, the testes are also infected, which can lead to sterility. Dental caries (kār'ēz; "rottenness"), or cavities, result from bacterial action that gradually demineralizes enamel and underlying dentin. In periodontitis, neutrophils and other immune cells attack body tissues, carving deep pockets around the teeth. As dental plaque accumulates, it calcifies, forming calculus (kal'ku-lus; "stone") or tartar. These stony hard deposits disrupt the seal between gingivae and teeth, deepening the sulcus and putting the gums at risk for infection by pathogenic anaerobic bacteria. In the early stages of such an infection, called gingivitis (jin"jĭ-vi'tis), the gums are red, sore, swollen, and may bleed.
Question: Select the phase of gastric secretion that occurs before food enters the stomach.
Answer: Cephalic Description: The cephalic phase of gastric secretion occurs before food enters the stomach. Stimuli acting at three distinct sites—the head, stomach, and small intestine—provoke or inhibit gastric secretions. Accordingly, the three phases of gastric secretion are called the cephalic, gastric, and intestinal phases. One or more phases may occur at the same time. The cephalic, or reflex, phase of gastric secretion occurs before food enters the stomach. Only a few minutes long, this phase is triggered by the aroma, taste, sight, or thought of food. These triggers act via the vagus nerve to stimulate gastric glands, getting the stomach ready for its digestive chore.
Question: Match the following: Barrett's esophagus
Answer: Change in the epithelium of the lower esophagus from stratified squamous to a columnar epithelium Description: Barrett's esophagus is a pathological change in the epithelium of the lower esophagus from stratified squamous to a columnar epithelium. A possible sequel to untreated chronic gastroesophageal reflux due to hiatal hernia, it predisposes the individual to aggressive esophageal cancer (adenocarcinoma). Achalasia is a disorder in which swallowing is hindered or prevented. Botox injections can relax the esophageal sphincter. Abnormal accumulation of fluid within the peritoneal cavity is called ascites. Difficulty swallowing is called dysphagia. Abnormal grinding or clenching of teeth, usually during sleep, is called bruxism. Overeating followed by purging occurs in bulimia.
Question: Select the true statement regarding digestive function in the stomach.
Answer: Churning action causes mechanical breakdown of stomach contents. Description: It is a true statement that churning action causes mechanical breakdown of stomach contents. The churning action provided by the stomach's smooth muscle during peristalsis causes mechanical breakdown of stomach contents. Like the esophagus, the stomach exhibits peristalsis. Segmentation only occurs in the small intestine. Protein digestion begins in the stomach and is the main type of enzymatic breakdown that occurs there. The most important protein-digesting enzyme produced by the gastric mucosa is pepsin. Digestion of carbohydrates begins with salivary amylase in the mouth.Not much is absorbed in the stomach, but two common lipid-soluble substances—alcohol and aspirin—pass easily through the stomach mucosa into the blood.
Question: Which phrase describes the pylorus region of the stomach?
Answer: Continuous with the small intestine Description: The pylorus is continuous with the small intestine. The small cardia surrounds the cardial orifice through which food enters the stomach from the esophagus. The fundus is the stomach's dome-shaped part, tucked beneath the diaphragm, that bulges superolaterally to the cardia. The body, or the mid-portion of the stomach, is continuous inferiorly with the funnel-shaped pyloric part. The wider and more superior area of the pyloric part, the pyloric antrum, narrows to form the pyloric canal, which terminates at the pylorus. The pylorus is continuous with the duodenum through the pyloric sphincter or valve, which controls stomach emptying.
Question: Select the description for the structure labeled 'D.'
Answer: Covers the root of the tooth Description: "D" is the cement which covers the root of the tooth. Each tooth has two major regions: the crown and the root. The enamel-covered crown is the exposed part of the tooth above the gingiva (jin'jĭ-vah), or gum, which surrounds the tooth like a tight collar. Enamel, a brittle ceramic-like material thick as a dime, directly bears the force of chewing. The hardest substance in the body, it is heavily mineralized with calcium salts, and its densely packed hydroxyapatite (mineral) crystals are oriented in force-resisting columns perpendicular to the tooth's surface. The cells that produce enamel degenerate when the tooth erupts; consequently, decayed or cracked areas of enamel will not heal and must be artificially filled. The root is the portion of the tooth embedded in the jawbone. Canine teeth, incisors, and premolars have one root, although the first upper premolars commonly have two. The first two upper molars have three roots, while the corresponding lower molars have two. The root pattern of the third molar varies, but a fused single root is most common. A constricted tooth region called the neck connects the crown and root. Cement, a calcified connective tissue, covers the outer surface of the root and attaches the tooth to the thin periodontal ligament (per"e-o-don'tal; "around the tooth"). This ligament anchors the tooth in the bony socket (alveolus) of the jaw, forming a fibrous joint called a gomphosis. Where the gingiva borders on a tooth, it dips downward to form a shallow groove called the gingival sulcus. Dentin, a protein-rich bone-like material, underlies the enamel cap and forms the bulk of a tooth. More resilient than enamel, dentin acts as a shock absorber during biting and chewing. Dentin surrounds a central pulp cavity containing a number of soft tissue structures (connective tissue, blood vessels, and nerve fibers) collectively called pulp. Pulp supplies nutrients to the tooth tissues and provides tooth sensation. Where the pulp cavity extends into the root, it becomes the root canal.
Question: Select the duct that drains the gallbladder.
Answer: Cystic duct Description: The cystic duct drains the gallbladder. Bile leaves the liver lobes through the right and left hepatic ducts. These fuse to form the large common hepatic duct, which travels downward toward the duodenum. Along its course, that duct fuses with the cystic duct draining the gallbladder to form the bile duct.
Question: Match the following: Dysphagia
Answer: Difficulty swallowing Description: Dysphagia (dis-fa'je-ah; dys = difficult, abnormal; phag = eat): Difficulty swallowing; usually due to obstruction or physical trauma to the esophagus. Achalasia is a disorder in which swallowing is hindered or prevented. Botox injections can relax the esophageal sphincter. Abnormal accumulation of fluid within the peritoneal cavity is called ascites. A change in the epithelium of the lower esophagus from stratified squamous to a columnar epithelium is called Barrett's esophagus. Abnormal grinding or clenching of teeth, usually during sleep, is called bruxism. Overeating followed by purging occurs in bulimia.
Question: In order to prevent self-digestion of the pancreas, activation of pancreatic proteases occurs in the __________.
Answer: Duodenum Description: In order to prevent self-digestion of the pancreas, activation of pancreatic proteases occurs in the duodenum. Approximately 1200 to 1500 ml of clear pancreatic juice is produced daily. It consists mainly of water, and contains enzymes and electrolytes (primarily bicarbonate ions). The high pH of pancreatic fluid helps neutralize acidic chyme entering the duodenum and provides the optimal environment for intestinal and pancreatic enzymes. The pancreatic enzymes include: Proteases (for proteins) Amylase (for starch) Lipases (for fats) Nucleases (for nucleic acids) Like pepsin of the stomach, pancreatic proteases are produced and released in inactive forms that are activated in the duodenum, where they do their work. This protects the pancreas from digesting itself. For example, within the duodenum, enteropeptidase (formerly called enterokinase), an enzyme bound to the plasma membrane of duodenal epithelial cells, activates trypsinogen to trypsin. Trypsin, in turn, activates more trypsinogen and two other pancreatic proteases (procarboxypeptidase and chymotrypsinogen) to their active forms, carboxypeptidase (kar-bok"se-pep'tĭ-dās) and chymotrypsin (ky"mo-trip'sin), respectively.
Question: Match the following digestive process with the correct description: Chemical digestion
Answer: Enzymatic degradation of foodstuffs into simpler molecules Description: Chemical digestion is described as the enzymatic degradation of foodstuffs into simpler molecules. Digestion involves a series of catabolic steps in which enzymes secreted into the lumen (cavity) of the alimentary canal break down complex food molecules to their chemical building blocks. Absorption is the passage of digested end products (plus vitamins, minerals, and water) from the lumen of the GI tract through the mucosal cells by active or passive transport into the blood or lymph. Taking food into the digestive system is called ingestion. Chewing, mixing, churning, and segmentation are part of mechanical digestion. Elimination of indigestible solids is the process of defecation.
Question: Match the following: Hemochromatosis
Answer: Excess iron is deposited in the tissues, increasing skin pigmentation and the risk of hepatic cancer and liver cirrhosis
Answer: Match the structure in or around the oral cavity with its description: Sublingual gland.
Answer: Salivary gland below the tonge. Description: The sublingual gland is the salivary gland below the tongue. The small, almond-shaped sublingual gland lies anterior to the submandibular gland under the tongue and opens via 10-20 ducts into the floor of the mouth. About the size of a walnut, the submandibular gland lies along the medial aspect of the mandibular body. Its duct runs beneath the mucosa of the oral cavity floor and opens at the base of the lingual frenulum.
Question: Match the following part of a tooth with its description: Crown.
Answer: Exposed and covered in enamel Description: The crown is exposed and covered in enamel. Each tooth has two major regions: the crown and the root. The enamel-covered crown is the exposed part of the tooth above the gingiva (jin'jĭ-vah), or gum, which surrounds the tooth like a tight collar. Enamel, a brittle ceramic-like material thick as a dime, directly bears the force of chewing. The hardest substance in the body, it is heavily mineralized with calcium salts, and its densely packed hydroxyapatite (mineral) crystals are oriented in force-resisting columns perpendicular to the tooth's surface. The cells that produce enamel degenerate when the tooth erupts; consequently, decayed or cracked areas of enamel will not heal and must be artificially filled.
Question: Match the following: Xerostomia
Answer: Extreme dryness of the mouth Description: Xerostomia (ze"ro-sto'me-ah; zer = dry, stom = mouth): Extreme dryness of the mouth; can be caused by cysts that block salivary glands or autoimmune invasion of the salivary glands or ducts (Sjogren's syndrome). Enteritis is an inflammation of the intestine, especially the small intestine. Excess iron deposited in the tissues is called hemochromatosis. When all GI tract movement stops and the gut appears to be paralyzed, this is called ileus. A noncontagious, periodic inflammation of the intestinal wall occurs in inflammatory bowel disease (IBD). Pancreatitis may result from excessively high levels of fat in the blood or excessive alcohol ingestion, but most acute cases arise from gallstones that block the bile duct.
Question: Which of the following factors do not directly cause vomiting?
Answer: Fever Description: A fever does not directly cause vomiting. Vomiting, or emesis, is an unpleasant experience that empties the stomach by a different route. Many factors signal the stomach to "launch lunch," but the most common are extreme stretching of the stomach or intestine or irritants such as bacterial toxins, excessive alcohol, spicy foods, and certain drugs. Bloodborne molecules and sensory impulses stream from the irritated sites to the emetic center (e-met'ik) of the medulla where they initiate a number of motor responses. Before vomiting, an individual typically feels nauseated, is pale, and salivates excessively. A deep inspiration directly precedes vomiting. The diaphragm and abdominal wall muscles contract, increasing intra-abdominal pressure, the gastroesophageal sphincter relaxes, and the soft palate rises to close off the nasal passages. As a result, the stomach (and perhaps duodenal) contents are forced upward through the esophagus and pharynx and out the mouth. Excessive vomiting can cause dehydration and severely disrupt the body's electrolyte and acid-base balance. Since large amounts of HCl are lost in vomitus, the blood becomes alkaline as the stomach attempts to replace its lost acid.
Question: Match the following part of a tooth with its description: Periodontal ligament.
Answer: Forms the support of the gomphosis Description: The periodontal ligament forms the support of the gomphosis. A constricted tooth region called the neck connects the crown and root. Cement, a calcified connective tissue, covers the outer surface of the root and attaches the tooth to the thin periodontal ligament (per"e-o-don'tal; "around the tooth"). This ligament anchors the tooth in the bony socket (alveolus) of the jaw, forming a fibrous joint called a gomphosis. Where the gingiva borders on a tooth, it dips downward to form a shallow groove called the gingival sulcus.
Question: Which of the following products does the stomach produce?
Answer: HCl and intrinsic factor Description: The stomach produces HCl and intrinsic factor. Except for ingestion and defecation, the stomach is involved in the whole "menu" of digestive activities. Besides serving as a holding area for ingested food, the stomach continues the demolition job begun in the oral cavity by further degrading food both physically and chemically. It then delivers chyme, the product of its activity, into the small intestine. Protein digestion begins in the stomach and is the main type of enzymatic breakdown that occurs there. HCl produced by stomach glands denatures dietary proteins in preparation for enzymatic digestion. (The unfolded amino acid chain is more accessible to the enzymes.) The most important protein-digesting enzyme produced by the gastric mucosa is pepsin. In infants, however, the stomach glands also secrete rennin, an enzyme that acts on milk protein (casein), converting it to a curdy substance that looks like soured milk. Fat digestion occurs primarily in the small intestine, but gastric and lingual lipases acting in the acidic pH of the stomach also contribute. Not much is absorbed in the stomach, but two common lipid-soluble substances—alcohol and aspirin—pass easily through the stomach mucosa into the blood. Despite the obvious benefits of preparing food to enter the intestine, the only stomach function essential to life is secretion of intrinsic factor. Intrinsic factor is required for intestinal absorption of vitamin B12, needed to produce mature erythrocytes. In its absence, pernicious anemia results. However, if vitamin B12 is administered by injection, individuals can survive with minimal digestive problems even after total gastrectomy (stomach removal). The table below summarizes the stomach's activities.
Question: __________ circulation collects nutrient-rich blood from the GI tract and delivers it to the liver.
Answer: Hepatic portal Description: The hepatic portal circulation collects nutrient-rich blood from the GI tract and delivers it to the liver. If you keep in mind that the liver's main function is to process the nutrient-rich blood delivered to it, its histology makes a lot of sense. At each of the six corners of a lobule is a portal triad (portal tract region), so named because it contains three basic structures: A branch of the hepatic artery proper (supplying oxygen-rich arterial blood to the liver) A branch of the hepatic portal vein (carrying venous blood laden with nutrients from the digestive viscera) A bile duct
Question: What structure of the small intestine contains the sphincter/valve that connects to the large intestine?
Answer: Ileum Description: The ileum contains the valve that connects to the large intestine. The small intestine has three subdivisions: the duodenum, which is mostly retroperitoneal, and the jejunum and ileum, both intraperitoneal organs. The relatively immovable duodenum (du"o-de'num; "twelve finger widths long"), which curves around the head of the pancreas, is about 25 cm (10 inches) long. Although it is the shortest intestinal subdivision, the duodenum has the most features of interest, including the major duodenal papilla. The jejunum (jĕ-joo'num; "empty"), about 2.5 m (8 ft) long, extends from the duodenum to the ileum. The ileum (il'e-um; "twisted"), approximately 3.6 m (12 ft) in length, joins the large intestine at the ileocecal valve. The jejunum and ileum hang in sausagelike coils in the central and lower part of the abdominal cavity, suspended from the posterior abdominal wall by a fan-shaped mesentery. The large intestine encircles these more distal parts of the small intestine.
Question: Which of the following is not a common cause of malabsorption?
Answer: Improper bowel habits (failing to heed the "call"), lack of exercise, or laxative abuse Description: Improper bowel habits (failing to heed the "call"), lack of exercise, or laxative abuse, is not a common cause of malabsorption. Malabsorption, or impaired nutrient absorption, has many and varied causes. It can result from anything that interferes with the delivery of bile or pancreatic juice to the small intestine. Factors that damage the intestinal mucosa (severe bacterial infections and some antibiotics) or reduce its absorptive surface area are also common causes. Constipation may result from insufficient fiber or fluid in the diet, improper bowel habits (failing to heed the "call"), lack of exercise, or laxative abuse.
Question: Match the following hormone involved in gastric secretion with its description: CCK
Answer: Increases the secretions of enzyme-rich pancreatic juice Description: CCK increases the secretions of enzyme-rich pancreatic juice. The enterogastrone hormones are released by a scattering of enteroendocrine cells in the duodenal mucosal epithelium. The two most improtant enterogastrones are secretin (se-kre'tin) and cholecystokinin (CCK) (ko"le-sis"to-ki'nin). The enterogastrones inhibit gastric secretion and also play other roles.
Question: Match the following hormone involved in gastric secretion with its description: Secretin
Answer: Inhibits gastric gland secretions and stimulates the release of bicarbonate-rich pancreatic juice Description: Secretin inhibits gastric gland secretions and stimulates the release of bicarbonate-rich pancreatic juice. The enterogastrone hormones are released by a scattering of enteroendocrine cells in the duodenal mucosal epithelium. The two most improtant enterogastrones are secretin (se-kre'tin) and cholecystokinin (CCK) (ko"le-sis"to-ki'nin). The enterogastrones inhibit gastric secretion and also play other roles.
Question: Which of the following is not an accessory organ of the digestive system?
Answer: Intestines Description: The intestines are not accessory digestive organs. The accessory digestive organs are the teeth, tongue, gallbladder, and a number of large digestive glands—the salivary glands, liver, and pancreas. The teeth and tongue are in the mouth, or oral cavity, while the digestive glands and gallbladder lie outside the GI tract and connect to it by ducts. The accessory digestive glands produce a variety of secretions that help break down foodstuffs.
Question: Which of the following is a characteristic of the large intestine?
Answer: It contains a large number of bacteria. Description: The large intestine contains a large number of bacteria. The large intestine frames the small intestine on three sides and extends from the ileocecal valve to the anus. Its diameter, at about 7 cm, is greater than that of the small intestine, but it is much shorter (1.5 m versus 6 m). Its major digestive functions are to absorb most of the remaining water from indigestible food residues, store the residues temporarily, and then eliminate them from the body as semisolid feces (fe'sēz), also called stool. It also absorbs metabolites produced by resident bacteria as they ferment carbohydrates not absorbed in the small intestine.
Question: Which of the following is not a characteristic of the liver?
Answer: It has three lobes. Description: It is NOT a characteristic of the liver that it has three lobes. The liver has four primary lobes. The largest, the right lobe, is visible on all liver surfaces and separated from the smaller left lobe by a deep fissure. The posteriormost caudate lobe and the quadrate lobe, which lies inferior to the left lobe, are visible in an inferior view of the liver. The versatile hepatocytes have large amounts of both rough and smooth ER, Golgi apparatus, peroxisomes, and mitochondria. Equipped in this way, the hepatocytes can: Secrete some 900 ml of bile daily Process bloodborne nutrients in various ways (e.g., they store glucose as glycogen and use amino acids to make plasma proteins) Store fat-soluble vitamins Play important roles in detoxification, such as ridding the blood of ammonia by converting it to urea
Question: Which of the following statements about the mesentery is incorrect?
Answer: It is composed of a layer of serous membrane fused with a layer of mucus membrane. Description: It is incorrect that the mesentery is composed of a layer of serous membrane fused with a layer of mucus membrane. A mesentery (mes'en-ter"e) is a double layer of peritoneum—a sheet of two serous membranes fused back to back—that extends to the digestive organs from the body wall. Mesenteries provide routes for blood vessels, lymphatics, and nerves to reach the digestive viscera, hold organs in place, and store fat. In most places the mesentery is dorsal and attaches to the posterior abdominal wall, but there are ventral mesenteries too, such as the one that extends from the liver to the anterior abdominal wall digestive organ mesenteries have specific names (such as the omenta), or are called "ligaments" (even though these peritoneal folds are nothing like the fibrous ligaments that connect bones).
Question: Identify the structure within the small intestine indicated by "D."
Answer: Lacteal
Question: Match the structure in or around the oral cavity with its description: Parotid gland.
Answer: Large salivary gland lying near the ear Description: The parotid gland is the large salivary gland lying near the ear. The major salivary glands are paired compound tubuloalveolar glands that develop from the oral mucosa and remain connected to it by ducts. The large, roughly triangular parotid gland (pah-rot'id; par = near, oto = the ear) lies anterior to the ear between the masseter muscle and the skin. Its prominent duct parallels the zygomatic arch, pierces the buccinator muscle, and opens into the vestibule next to the second upper molar.
Question: Match the following term to its correct description: Mucosa
Answer: Main site of nutrient absorption Description: The mucosa is the main site of nutrient absorption. The innermost layer is the mucosa, or mucous membrane, a moist epithelial membrane that lines the alimentary canal lumen from mouth to anus. Its major functions are to: Secrete mucus, digestive enzymes, and hormones Absorb the end products of digestion into the blood Protect against infectious disease The mucosa in a particular region of the GI tract may perform one or all three of these functions. The protective outer layer of the alimentary canal is the serosa. Areolar connective tissue that has a rich supply of blood, lymphatic vessels, and nerve fibers is the submucosa. The muscularis externa is responsible for segmentation and peristalsis.
Question: Match the following term with its correct description: In direct contact with ingested food.
Answer: Mucosa Description: The mucosa is in direct contact with ingested food. The innermost layer is the mucosa, or mucous membrane, a moist epithelial membrane that lines the alimentary canal lumen from mouth to anus. Its major functions are to: Secrete mucus, digestive enzymes, and hormones Absorb the end products of digestion into the blood Protect against infectious disease The mucosa in a particular region of the GI tract may perform one or all three of these functions. More complex than most other mucosae in the body, the typical digestive mucosa consists of three sublayers: (1) a lining epithelium, (2) a lamina propria, and (3) a muscularis mucosae. Except for that of the mouth, esophagus, and anus where it is stratified squamous, the epithelium of the mucosa is a simple columnar epithelium rich in mucus-secreting cells. The slippery mucus it produces protects certain digestive organs from being digested by enzymes working within their cavities and eases food passage along the tract. In the stomach and small intestine, the mucosa also contains both enzyme-synthesizing and hormone-secreting cells. In such sites, the mucosa is a diffuse endocrine organ as well as part of the digestive organ.
Question: Which sequence below represents the correct layering of the wall of the GI tract, starting from the layer next to the lumen?
Answer: Mucosa, submucosa, muscularis externa, serosa Description: The correct layering of the wall of the GI tract, starting from the layer next to the lumen is mucosa, submucosa, muscularis externa, serosa. From the esophagus to the anal canal, the walls of the alimentary canal have the same four basic layers, or tunics—mucosa, submucosa, muscularis externa, and serosa. Each layer contains a predominant tissue type that plays a specific role in food breakdown.
Question: The alimentary canal in a cadaver is longer than in a living person because, in a cadaver, there is no __________.
Answer: Muscle tone Description: The alimentary canal in a cadaver is longer than in a living person because, in a cadaver, there is no muscle tone. The organs of the alimentary canal are the mouth, pharynx, esophagus, stomach, small intestine, and large intestine. The large intestine leads to the terminal opening, or anus. In a cadaver, the alimentary canal is approximately 9 m (about 30 ft) long, but in a living person, it is considerably shorter because of its muscle tone. Food material in this tube is technically outside the body because the canal is open to the external environment at both ends.
Question: Match the following: Periodontitis.
Answer: Neutrophils and other immune cells attack body tissues, carving deep pockets around the teeth. Description: In periodontitis, neutrophils and other immune cells attack body tissues, carving deep pockets around the teeth. Gingivitis is reversible if the calculus is removed, but if it is neglected the bacteria eventually form pockets of infection which become inflamed. Neutrophils and other immune cells attack not only the intruders but also body tissues, carving deep pockets around the teeth, destroying the periodontal ligament, and activating osteoclasts which dissolve the bone. This serious condition, periodontal disease or periodontitis, affects up to 95% of all people over age 35 and accounts for 80-90% of tooth loss in adults. Tooth loss from periodontitis is not inevitable. Various treatments can alleviate the bacterial infestations and encourage the surrounding tissues to reattach to the teeth and bone.
Question: What type of epithelium is the esophageal mucosa lined with?
Answer: Nonkeratinized stratified squamous Description: The esophageal mucosa lined with nonkeratinized stratified squamous epithelium. At the esophagus-stomach junction, that abrasion-resistant epithelium changes abruptly to the simple columnar epithelium of the stomach, which is specialized for secretion.
Question: Match the following: Bulemia
Answer: Overeating followed by purging Description: Bulimia (bu-lim'e-ah; bous = ox; limos = hunger): Binge-purge behavior—episodes of overeating followed by purging (self-induced vomiting, taking laxatives or diuretics, or excessive exercise). It is most common in women of high school or college age, and foten associated with stress and depression. Consequences include eroded tooth enamel, stomach trauma or rupture (from vomiting), and severe electrolyte disturbances which impair heart activity. Therapy includes hospitalization to control behavior, and nutritional counseling. Achalasia is a disorder in which swallowing is hindered or prevented. Botox injections can relax the esophageal sphincter. Abnormal accumulation of fluid within the peritoneal cavity is called ascites. A change in the epithelium of the lower esophagus from stratified squamous to a columnar epithelium is called Barrett's esophagus. Difficulty swallowing is called dysphagia. Abnormal grinding or clenching of teeth, usually during sleep, is called bruxism.
Question: Which of the following cells produce HCl?
Answer: Parietal cells Description: Parietal cells, found mainly in the more apical region of the glands scattered among the chief cells, simultaneously secrete hydrochloric acid (HCl) and intrinsic factor. Although parietal cells appear oval when viewed with a light microscope, they actually have three prongs that bear dense microvilli (they look like fuzzy pitchforks!). This structure provides a huge surface area for secreting H+ and Cl− into the stomach lumen. HCl makes the stomach contents extremely acidic (pH 1.5-3.5), a condition necessary for activation and optimal activity of the protein-digesting enzyme pepsin. The acidity also helps digest food by denaturing proteins and breaking down cell walls of plant foods, and is harsh enough to kill many of the bacteria ingested with foods. Intrinsic factor is a glycoprotein required for vitamin B12 absorption in the small intestine.
Question: Match the following digestive process with the correct description: Absorption
Answer: Passage of digested materials from the lumen of the GI tract into the blood or lymph Description: Absorption is the passage of digested end products (plus vitamins, minerals, and water) from the lumen of the GI tract through the mucosal cells by active or passive transport into the blood or lymph. Taking food into the digestive system is called ingestion. Chewing, mixing, churning, and segmentation are part of mechanical digestion. Enzymatic degradation of foodstuffs into simpler molecules is chemical digestion. Elimination of indigestible solids is the process of defecation.
Question: __________ is the major means of propulsion in the digestive system.
Answer: Peristalsis Description: Peristalsis is the major means of propulsion in the digestive system. Propulsion, which moves food through the alimentary canal, includes swallowing, which is initiated voluntarily, and peristalsis (per"ĭ-stal'sis), an involuntary process. Peristalsis (peri = around; stalsis = constriction), the major means of propulsion, involves alternating waves of contraction and relaxation of muscles in the organ walls. Its main effect is to squeeze food along the tract, but some mixing occurs as well. In fact, peristaltic waves are so powerful that, once swallowed, food and fluids will reach your stomach even if you stand on your head.
Question: How does food move through the esophagus to the stomach?
Answer: Perostalsis Description: After swallowing, food moves through the esophagus and to the stomach by peristalsis.The pharyngeal-esophageal phase is involuntary and is controlled by the swallowing center in the brain stem (medulla and lower pons). Various cranial nerves, most importantly the vagus nerves, transmit motor impulses from the swallowing center to the muscles of the pharynx and esophagus. Once food enters the pharynx, respiration is momentarily inhibited and all routes except the desired one into the digestive tract are blocked off. Solid foods pass from the oropharynx to the stomach in about 8 seconds, and fluids, aided by gravity, pass in 1 to 2 seconds.
Question: Identify the organ indicated by 'B.'
Answer: Pharynx
Question: Match the digestive system cell with its correct characteristic: Paneth.
Answer: Produces lysozyme Description: Paneth cells produce lysozyme. Paneth cells, found deep in the crypts, are specialized secretory cells that fortify the small intestine's defenses by releasing antimicrobial agents such as defensins and lysozyme. These secretions destroy certain bacteria and help to determine which bacteria colonize the intestinal lumen. Intrinsic factor is made by the parietal cells of the stomach.
Question: Select the pancreatic enzymes that digest proteins.
Answer: Proteases Description: Pancreatic enzymes called proteases digest proteins. Approximately 1200 to 1500 ml of clear pancreatic juice is produced daily. It consists mainly of water, and contains enzymes and electrolytes (primarily bicarbonate ions). The high pH of pancreatic fluid helps neutralize acidic chyme entering the duodenum and provides the optimal environment for intestinal and pancreatic enzymes. The pancreatic enzymes include: Proteases (for proteins) Amylase (for starch) Lipases (for fats) Nucleases (for nucleic acids) Like pepsin of the stomach, pancreatic proteases are produced and released in inactive forms that are activated in the duodenum, where they do their work. This protects the pancreas from digesting itself.
Question: Match the following term to its correct description: Serosa
Answer: Protective outermost layer of the alimentary canal Description: The serosa is the protective outermost layer of the alimentary canal. The serosa, the outermost layer of the intraperitoneal organs, is the visceral peritoneum. In most alimentary canal organs, it is formed of areolar connective tissue covered with mesothelium, a single layer of squamous epithelial cells. In the esophagus, which is located in the thoracic instead of the abdominopelvic cavity, the serosa is replaced by an adventitia (ad"ven-tish'e-ah), ordinary dense connective tissue that binds the esophagus to surrounding structures. Retroperitoneal organs have both an adventitia (on the side facing the dorsal body wall) and a serosa (on the side facing the peritoneal cavity). The mucosa is the main site of nutrient absorption. Areolar connective tissue that has a rich supply of blood, lymphatic vessels, and nerve fibers is the submucosa. The muscularis externa is responsible for segmentation and peristalsis.
Question: What is the main organic molecule digested in the stomach?
Answer: Proteins Description: The main organic molecule digested in the stomach is proteins. Except for ingestion and defecation, the stomach is involved in the whole "menu" of digestive activities. Besides serving as a holding area for ingested food, the stomach continues the demolition job begun in the oral cavity by further degrading food both physically and chemically. It then delivers chyme, the product of its activity, into the small intestine. Protein digestion begins in the stomach and is the main type of enzymatic breakdown that occurs there. HCl produced by stomach glands denatures dietary proteins in preparation for enzymatic digestion. (The unfolded amino acid chain is more accessible to the enzymes.) The most important protein-digesting enzyme produced by the gastric mucosa is pepsin. In infants, however, the stomach glands also secrete rennin, an enzyme that acts on milk protein (casein), converting it to a curdy substance that looks like soured milk.
Question: Match the following term to its correct description: Muscularis externa
Answer: Responsible for segmentation and peristalsis The muscularis externa is responsible for segmentation and peristalsis. Surrounding the submucosa is the muscularis externa, also simply called the muscularis. This layer is responsible for segmentation and peristalsis. It typically has an inner circular layer and an outer longitudinal layer of smooth muscle cells. In several places along the tract, the circular layer thickens, forming sphincters that act as valves to control food passage from one organ to the next and prevent backflow. The mucosa is the main site of nutrient absorption. The protective outer layer of the alimentary canal is the serosa. Areolar connective tissue that has a rich supply of blood, lymphatic vessels, and nerve fibers is the submucosa.
Question: Match the following: Caries
Answer: Results from bacterial action that gradually demineralizes enamel. Description: Dental caries (kār'ēz; "rottenness"), or cavities, result from bacterial action that gradually demineralizes enamel and underlying dentin. Decay begins when dental plaque (a film of sugar, bacteria, and other mouth debris) adheres to the teeth. Bacterial metabolism of the trapped sugars produces acids, which dissolve the calcium salts of the teeth. Once the salts are leached out, enzymes released by the bacteria readily digest the remaining organic matrix of the tooth. Frequent brushing and daily flossing help prevent caries by removing plaque. As dental plaque accumulates, it calcifies, forming calculus (kal'ku-lus; "stone") or tartar. These stony hard deposits disrupt the seal between gingivae and teeth, deepening the sulcus and putting the gums at risk for infection by pathogenic anaerobic bacteria. In the early stages of such an infection, called gingivitis (jin"jĭ-vi'tis), the gums are red, sore, swollen, and may bleed. A burning, radiating substernal pain may be caused by gastroesophageal disease (GERD), in which stomach acid regurgitates into the esophagus. In 25% of mumps cases in adult males, the testes are also infected, which can lead to sterility.
Question: Select the description for the structure labeled 'B.'
Answer: Shock absorber during biting 'B' is denting which is a shock absorber during biting. Each tooth has two major regions: the crown and the root. The enamel-covered crown is the exposed part of the tooth above the gingiva (jin'jĭ-vah), or gum, which surrounds the tooth like a tight collar. Enamel, a brittle ceramic-like material thick as a dime, directly bears the force of chewing. The hardest substance in the body, it is heavily mineralized with calcium salts, and its densely packed hydroxyapatite (mineral) crystals are oriented in force-resisting columns perpendicular to the tooth's surface. The cells that produce enamel degenerate when the tooth erupts; consequently, decayed or cracked areas of enamel will not heal and must be artificially filled. The root is the portion of the tooth embedded in the jawbone. Canine teeth, incisors, and premolars have one root, although the first upper premolars commonly have two. The first two upper molars have three roots, while the corresponding lower molars have two. The root pattern of the third molar varies, but a fused single root is most common. A constricted tooth region called the neck connects the crown and root. Cement, a calcified connective tissue, covers the outer surface of the root and attaches the tooth to the thin periodontal ligament (per"e-o-don'tal; "around the tooth"). This ligament anchors the tooth in the bony socket (alveolus) of the jaw, forming a fibrous joint called a gomphosis. Where the gingiva borders on a tooth, it dips downward to form a shallow groove called the gingival sulcus. Dentin, a protein-rich bone-like material, underlies the enamel cap and forms the bulk of a tooth. More resilient than enamel, dentin acts as a shock absorber during biting and chewing. Dentin surrounds a central pulp cavity containing a number of soft tissue structures (connective tissue, blood vessels, and nerve fibers) collectively called pulp. Pulp supplies nutrients to the tooth tissues and provides tooth sensation. Where the pulp cavity extends into the root, it becomes the root canal.
Question: Most water is absorbed in the __________.
Answer: Small intestine Description: Most water is absorbed in the small intestine. By the time food reaches the small intestine, it is unrecognizable, but still far from being digested. Carbohydrates and proteins are partially degraded, but fat digestion has only begun. The process of digestion accelerates during the chyme's tortuous three to six-hour journey through the small intestine, and it is here that most of the water and virtually all nutrients are absorbed.
Question: The major site for nutrient absorption is the __________.
Answer: Small intestine Description: The major site for nutrient absorption is the small intestine. The small intestine is the body's major digestive organ. Within its twisted passageways, digestion is completed (with the help of bile and pancreatic enzymes) and virtually all absorption occurs.
Question: Match the following hormone involved in gastric secretion with its description: Gastrin
Answer: Stimulated by partially digested proteins in the stomach and increases gastric gland secretions Description: Gastrin release is stimulated by partially digested proteins in the stomach and increases gastric gland secretions. As seen in the table below, gastrin, a hormone released by the stomach, plays an essential role in regulating stomach secretion and motility.
Question: Match the following hormone involved in gastric secretion with its description: GIP
Answer: Stimulates insulin secretions; released in response to presence of fatty chyme in the small intestine Description: GIP stimulates insulin secretions and is released in response to presence of fatty chyme in the small intestine. As shown in the table below, GIP is released in response to fatty chyme where it inibits HCl production and stimulates insulin release.
Question: Which of the following causes the defecation reflex?
Answer: Stretching of the rectal wall Description: The rectum is usually empty, but when mass movements force feces into it, stretching of the rectal wall initiates the defecation reflex. This parasympathetic spinal reflex causes the sigmoid colon and the rectum to contract, and the internal anal sphincter to relax. As feces are forced into the anal canal, messages reach the brain allowing us to decide whether the external (voluntary) anal sphincter should open or remain constricted to stop passage of feces temporarily.
Question: Select the description for the structure labeled 'C.'
Answer: Surrounds the tooth like a collar Description: "C" is the gingiva, which surrounds a tooth like a collar. Each tooth has two major regions: the crown and the root. The enamel-covered crown is the exposed part of the tooth above the gingiva (jin'jĭ-vah), or gum, which surrounds the tooth like a tight collar. Enamel, a brittle ceramic-like material thick as a dime, directly bears the force of chewing. The hardest substance in the body, it is heavily mineralized with calcium salts, and its densely packed hydroxyapatite (mineral) crystals are oriented in force-resisting columns perpendicular to the tooth's surface. The cells that produce enamel degenerate when the tooth erupts; consequently, decayed or cracked areas of enamel will not heal and must be artificially filled. The root is the portion of the tooth embedded in the jawbone. Canine teeth, incisors, and premolars have one root, although the first upper premolars commonly have two. The first two upper molars have three roots, while the corresponding lower molars have two. The root pattern of the third molar varies, but a fused single root is most common. A constricted tooth region called the neck connects the crown and root. Cement, a calcified connective tissue, covers the outer surface of the root and attaches the tooth to the thin periodontal ligament (per"e-o-don'tal; "around the tooth"). This ligament anchors the tooth in the bony socket (alveolus) of the jaw, forming a fibrous joint called a gomphosis. Where the gingiva borders on a tooth, it dips downward to form a shallow groove called the gingival sulcus. Dentin, a protein-rich bone-like material, underlies the enamel cap and forms the bulk of a tooth. More resilient than enamel, dentin acts as a shock absorber during biting and chewing. Dentin surrounds a central pulp cavity containing a number of soft tissue structures (connective tissue, blood vessels, and nerve fibers) collectively called pulp. Pulp supplies nutrients to the tooth tissues and provides tooth sensation. Where the pulp cavity extends into the root, it becomes the root canal.
Question: Match the following: Achalasia
Answer: Swallowing is hindered or prevented Description: Achalasia is a disorder in which swallowing is hindered or prevented. Botox injections can relax the esophageal sphincter. Abnormal accumulation of fluid within the peritoneal cavity is called ascites. A change in the epithelium of the lower esophagus from stratified squamous to a columnar epithelium is called Barrett's esophagus. Abnormal grinding or clenching of teeth, usually during sleep, is called bruxism. Overeating followed by purging occurs in bulimia.
Question: Match the following: Gingivitis
Answer: The gums are red, sore, swollen, and may bleed. Description: In ginigivits, the gums are red, sore, swollen, and may bleed. As dental plaque accumulates, it calcifies, forming calculus (kal'ku-lus; "stone") or tartar. These stony hard deposits disrupt the seal between gingivae and teeth, deepening the sulcus and putting the gums at risk for infection by pathogenic anaerobic bacteria. In the early stages of such an infection, called gingivitis (jin"jĭ-vi'tis), the gums are red, sore, swollen, and may bleed. A burning, radiating substernal pain may be caused by gastroesophageal disease (GERD), in which stomach acid regurgitates into the esophagus. In 25% of mumps cases in adult males, the testes are also infected, which can lead to sterility.
Question: Which of the following phrases describes hepatitis C?
Answer: The most important infectious liver disease in the United States. Description: Hepatitis C has emerged as the most important infectious liver disease in the United States because it produces persistent or chronic liver infections. More than 4 million Americans are infected and over 10,000 die annually due to sequels of HVC infection. However, the life-threatening C form of hepatitis can now be successfully (and very expensively) treated by a 12-week combination drug therapy. Cirrhosis is the last stage of progressive chronic inflammation of the liver. Non-alcoholic fatty liver disease (NAFLD) has become the most common liver disease in North America. It affects about 30% of the general population, but 70% of the obese. Obesity and increased insulin resistance are associated with abnormal lipid metabolism and liver inflammation, which cause NAFLD. Cholelithiasis is caused by gallstones obstructing the flow of bile from the gallbladder.
Question: Match the following term with its correct description: Same structure as the visceral peritoneum.
Answer: The serosa Description: The serosa, the outermost layer of the intraperitoneal organs, is the visceral peritoneum. In most alimentary canal organs, it is formed of areolar connective tissue covered with mesothelium, a single layer of squamous epithelial cells. In the esophagus, which is located in the thoracic instead of the abdominopelvic cavity, the serosa is replaced by an adventitia (ad"ven-tish'e-ah), ordinary dense connective tissue that binds the esophagus to surrounding structures. Retroperitoneal organs have both an adventitia (on the side facing the dorsal body wall) and a serosa (on the side facing the peritoneal cavity).
Which of the following teeth are most commonly impacted?
Answer: Wisdom teeth Description: Wisdom teeth are the most commonly impacted. When a tooth remains trapped in the jawbone, it is said to be impacted. Impacted teeth can cause a good deal of pressure and pain and must be removed surgically. Wisdom teeth are most commonly involved.
Question: Hollow muscular organs, like the stomach act as reservoirs because of an intrinsic smooth muscle stress-relaxation response known as _________.
Answer: accommodation Description: Hollow muscular organs, like the stomach act as reservoirs because of an intrinsic smooth muscle stress-relaxation response known as accommodation. Gastric accommodation is the intrinsic ability of visceral smooth muscle to exhibit the stress-relaxation response (usually discussed with smooth muscle). In other words, the stomach can stretch without greatly increasing its tension and contracting expulsively. This capability is very important in hollow organs, like the stomach, that must serve as temporary reservoirs. Receptive relaxation of smooth muscle in the stomach fundus and body occurs both in anticipation of and in response to food moving through the esophagus and into the stomach. The swallowing center of the brain stem coordinates this process, which is mediated by the vagus nerves. Peristalsis (peri = around; stalsis = constriction), the major means of propulsion, involves alternating waves of contraction and relaxation of muscles in the organ walls
Question:The __________ is the first segment of the small intestine.
Answer: duodenum Description: The duodenum is the first segment of the small intestine. The small intestine has three subdivisions: the duodenum, which is mostly retroperitoneal, and the jejunum and ileum, both intraperitoneal organs (see figure above). The relatively immovable duodenum (du"o-de'num; "twelve finger widths long"), which curves around the head of the pancreas, is about 25 cm (10 inches) long (see figure below). Although it is the shortest intestinal subdivision, the duodenum has the most features of interest, including the major duodenal papilla mentioned earlier.
Question: The point at which the esophagus passes through the diaphragm is called the __________.
Answer: esophageal hiatus Description: The point at which the esophagus passes through the diaphragm is called the esophageal hiatus. The esophagus takes a fairly straight course through the mediastinum of the thorax. It pierces the diaphragm at the esophageal hiatus (hi-a'tus; "gap") to enter the abdomen. It joins the stomach at the cardial orifice within the abdominal cavity. The cardial orifice is surrounded by the gastroesophageal or cardiac sphincter (ga-strō-i-ˌsä-fə-ˈjē-əl), which is a physiological sphincter.
Question: Bacterial flora in the large intestine do not produce __________.
Answer: intrinsic factor Description: Bacterial flora in the large intestine do not produce intrinsic factor. Despite the obvious benefits of preparing food to enter the intestine, the only stomach function essential to life is secretion of intrinsic factor. Intrinsic factor is required for intestinal absorption of vitamin B12, needed to produce mature erythrocytes. In its absence, pernicious anemia results. However, if vitamin B12 is administered by injection, individuals can survive with minimal digestive problems even after total gastrectomy (stomach removal). Our gut bacteria help us by recovering energy from otherwise indigestible foods and synthesizing some vitamins. Fermentation. Gut bacteria ferment some of the indigestible carbohydrates and mucin in gut mucus. The resulting short-chain fatty acids can be absorbed and used for fuel by the body's cells. Unfortunately, fermentation also produces a mixture of gases (including dimethyl sulfide, H2, N2, CH4, and CO2). Some of these gases, such as dimethyl sulfide, are quite odorous (smelly). About 500 ml of gas (flatus) is produced each day, much more when we eat foods (such as beans) rich in indigestible carbohydrates. Vitamin synthesis. B complex vitamins and some of the vitamin K the liver needs to produce several clotting proteins are synthesized by gut bacteria.
Question: The plasma membranes of the __________ bear enzymes referred to as brush border enzymes, which complete the digestion of carbohydrates and proteins in the small intestine.
Answer: microvilli Description: The plasma membranes of the microvilli bear enzymes referred to asbrush border enzymes, which complete the digestion of carbohydrates and proteins in the small intestine. Microvilli are long, densely packed cytoplasmic extentions of the absorptive cells of the mucosa that give the mucosal surface a fuzzy appearance called the brush border. The plasma membranes of the microvilli bear enzymes referred to as brush border enzymes, which complete the digestion of carbohydrates and proteins in the small intestine.
Question: The final product of carbohydrate digestion is __________.
Answer: monosaccharides Description: The final product of carbohydrate digestion is monosaccharides. In the average diet, most (up to 60%) digestible carbohydrates are in the form of starch, with smaller amounts of disaccharides and monosaccharides. Only three monosaccharides are common in our diet: glucose, fructose, and galactose. The more complex carbohydrates that our digestive system is able to break down to monosaccharides are the disaccharides sucrose (table sugar), lactose (milk sugar), and maltose (grain sugar), and the polysaccharides glycogen and starch. Brush border enzymes break oligoaccharides and disaccharides into monosaccharides. Intestinal brush border enzymes further digest these products to monosaccharides. The most important brush border enzymes are dextrinase and glucoamylase, which act on oligosaccharides composed of more than three simple sugars, and maltase, sucrase, and lactase, which hydrolyze maltose, sucrose, and lactose respectively into their constituent monosaccharides. Because the intestine can absorb only monosaccharides, all dietary carbohydrates must be digested to monosaccharides to be absorbed.
Question: The myxovirus causes __________.
Answer: mumps Mumps, a common children's disease, is an inflammation of the parotid glands caused by the mumps virus (myxovirus), which spreads from person to person in saliva. If you check the location of the parotid glands in the figure below, you can understand why people with mumps complain that it hurts to open their mouth or chew. Other signs and symptoms include moderate fever and pain when swallowing acidic foods (pickles, grapefruit juice, etc.). Mumps in adult males carries a 25% risk of infecting the testes too, leading to sterility.
Question: During swallowing food moves from the mouth to the ___________.
Answer: oropharynx Description: During swallowing, food from the mouth enters the oropharynx next. To send food on its way from the mouth, it is first compacted by the tongue into a bolus and is then swallowed. This complicated process involves the coordinated activity of over 22 separate muscle groups. There are two major phases involved in deglutition, or swallowing. The buccal phase occurs in the mouth and is voluntary. It ends when a food bolus or a "bit of saliva" leaves the mouth and stimulates tactile receptors in the posterior pharynx, initiating the next phase. The pharyngeal-esophageal phase is involuntary and is controlled by the swallowing center in the brain stem (medulla and lower pons). Various cranial nerves, most importantly the vagus nerves, transmit motor impulses from the swallowing center to the muscles of the pharynx and esophagus. Once food enters the pharynx, respiration is momentarily inhibited and all routes except the desired one into the digestive tract are blocked off. Solid foods pass from the oropharynx to the stomach in about 8 seconds, and fluids, aided by gravity, pass in 1 to 2 seconds.
Question: The increased concentration of HCO3- in blood draining from the stomach during production of HCl is called __________.
Answer: the alkaline tide Description: The increased concentration of HCO3- in blood draining from the stomach during production of HCl is called the alkaline tide. The process of HCl formation within the parietal cells is shown in the figure below. When parietal cells are appropriately stimulated, H+ is actively pumped into the stomach lumen by H+-K+ ATPases (proton pumps). As acid is pumped into the stomach, base (HCO3−) is exported into the blood. This flow of base is called the alkaline tide.
Question: The short reflexes in the digestive system are mediated by __________.
Answer: the enteric nerve plexuses Description: The short reflexes in the digestive system are mediated by the enteric nerve plexuses. Short reflexes are mediated entirely by enteric nervous system plexuses in response to stimuli within the GI tract. Control of the patterns of segmentation and peristalsis is largely automatic, involving pacemaker cells and reflex arcs between enteric neurons in the same or different organs.
Question: During the intestinal phase of gastric regulation, __________.
Answer: the stomach is initially stimulated and later inhibited Description: During the intestinal phase of gastric regulation, the stomach is initially stimulated and later inhibited. The intestinal phase of gastric secretion begins with a brief stimulatory component followed by inhibition. Stimulation The initial stimulatory part of the intestinal phase is set into motion as partially digested food fills the first part (duodenum) of the small intestine. This stimulates intestinal mucosal cells to release intestinal (enteric) gastrin, a hormone that encourages the gastric glands to continue their secretory activity. This stimulatory effect is brief because it overridden by inhibitory stimuli as the intestine fills. Inhibition Four main factors in the duodenum cause it to put the "brakes" on gastric secretion. Distension of the duodenum or the presence of acidic, fatty, or hypertonic chyme all trigger both neuronal and hormonal signals to tell the stomach "whoa, enough already!" These same four factors also decrease gastric emptying. These brakes on gastric activity protect the small intestine from excessive acidity. They also prevent a massive influx of chyme from overwhelming the digestive and absorptive capacities of the duodenum by matching the amount of entering chyme to the processing abilities of the small intestine. Inhibition is achieved in two ways: Enterogastric reflex: The duodenum inhibits acid secretion in the stomach by short reflexes through the enteric nervous system and by long reflexes involving sympathetic and vagus nerves. Enterogastrones: The enterogastrone hormones are released by a scattering of enteroendocrine cells in the duodenal mucosal epithelium. The two most important enterogastrones are secretin (se-kre'tin) and cholecystokinin (CCK) (ko"le-sis"to-ki'nin). The enterogastrones inhibit gastric secretion and also play other roles.
Question: The serous membrane that covers the external surface of most digestive organs is called the __________.
Answer: visceral peritoneum Description: The serous membrane that covers the external surface of most digestive organs is called the visceral peritoneum. Most digestive system organs reside in the abdomino pelvic cavity. All ventral body cavities contain slippery serous membranes. The peritoneum of the abdomino pelvic cavity is the most extensive of these membranes. The visceral peritoneum covers the external surfaces of most digestive organs and is continuous with the parietal peritoneum that lines the body wall. Between the two peritoneums is the peritoneal cavity, a slit like potential space containing a slippery fluid secreted by the serous membranes. The omenta are two mesenteries that help tether the stomach to other digestive organs and the body wall.
Question: Match the structure in or around the oral cavity with its description: Parotid gland.
Answer:Large salivary gland lying near the ear Description: The parotid gland is the large salivary gland lying near the ear. The major salivary glands are paired compound tubuloalveolar glands that develop from the oral mucosa and remain connected to it by ducts. The large, roughly triangular parotid gland (pah-rot'id; par = near, oto = the ear) lies anterior to the ear between the masseter muscle and the skin. Its prominent duct parallels the zygomatic arch, pierces the buccinator muscle, and opens into the vestibule next to the second upper molar.