1.
Chewing of food
Correct Answer
B. Mastication
Explanation
Mastication refers to the process of chewing food. It is an important step in the digestion process as it breaks down food into smaller pieces, making it easier to swallow and digest. Chewing also helps to mix food with saliva, which contains the enzyme amylase. Amylase helps to initiate the breakdown of carbohydrates in the food. Therefore, mastication plays a crucial role in the initial digestion of food before it enters the stomach.
2.
Breaks down starch
Correct Answer
A. Amylase
Explanation
Amylase is an enzyme that breaks down starch into simpler sugars. It is produced in the salivary glands and pancreas and helps in the digestion of carbohydrates. This enzyme starts breaking down starch into maltose in the mouth during the process of mastication. Therefore, amylase is the correct answer as it directly relates to the process of breaking down starch.
3.
Blood vessels, nerves, and lymphatic vessels that supply the intestinal wall
Correct Answer
C. Mesentery
Explanation
The mesentery is a fold of tissue that attaches the intestines to the abdominal wall. It contains blood vessels, nerves, and lymphatic vessels that supply the intestinal wall. This allows for the transportation of nutrients and waste products to and from the intestines. The mesentery also helps to support and stabilize the intestines within the abdominal cavity.
4.
Generate slow waves of electrical activity
Correct Answer
D. Interstitial cells of Cajal
Explanation
Interstitial cells of Cajal are specialized cells found in the gastrointestinal tract that generate slow waves of electrical activity. These electrical waves are essential for coordinating the contractions of the smooth muscles in the digestive system, allowing for proper movement of food through the intestines. These cells act as pacemakers, setting the rhythm and frequency of the contractions. Without the interstitial cells of Cajal, the smooth muscles would not contract in a coordinated manner, leading to digestive issues such as slowed transit time or bowel obstruction.
5.
Largest serous membrane in the body
Correct Answer
E. Peritoneum
Explanation
The peritoneum is the largest serous membrane in the body. It lines the abdominal cavity and covers the organs within it. It is composed of two layers, the parietal peritoneum which lines the abdominal wall, and the visceral peritoneum which covers the organs. The peritoneum helps to protect and support the organs, as well as provide a smooth surface for them to move against each other during digestion. It also plays a role in the immune response and the absorption of nutrients.
6.
Controls function of each segment of intestinal tract
Correct Answer
F. Submucosal plexus
Explanation
The submucosal plexus is a network of nerve fibers located in the submucosa layer of the intestinal tract. It controls the function of each segment of the intestinal tract by regulating the secretion of enzymes, absorption of nutrients, and movement of smooth muscles. This plexus coordinates the contraction and relaxation of the intestinal walls, allowing for the mixing and propulsion of food through the digestive system. It also plays a role in regulating blood flow and immune responses in the intestines. Therefore, the submucosal plexus is responsible for controlling the function of each segment of the intestinal tract.
7.
Segmental mixing movements of the large intestine
Correct Answer
G. Haustrations
Explanation
Haustrations refer to the contractions and relaxations of the circular muscles in the large intestine, which create pouch-like structures called haustra. These movements help to mix and propel the contents of the large intestine, allowing for further absorption of water and electrolytes. Haustrations also aid in the formation of feces by promoting the movement of waste material through the colon.
8.
Result of chemical breakdown of proteins in stomach
Correct Answer
H. Chyme
Explanation
Chyme is the correct answer because it refers to the result of the chemical breakdown of proteins in the stomach. After proteins are broken down by enzymes, such as pepsin, in the stomach, they form a semi-fluid mixture called chyme. Chyme is then gradually released into the small intestine for further digestion and absorption of nutrients.
9.
Responsible for motility along the length of the gut
Correct Answer
I. Myenteric plexus
Explanation
The myenteric plexus is responsible for motility along the length of the gut. It is a network of nerves located between the circular and longitudinal muscle layers of the gastrointestinal tract. The myenteric plexus controls the contraction and relaxation of the muscles in the gut, which allows for the movement of food and waste materials through the digestive system. It plays a crucial role in regulating peristalsis, the rhythmic contractions that propel food through the intestines.
10.
Inhibits gastric acid secretion
Correct Answer
J. Secretin
Explanation
Secretin is a hormone that is released by the small intestine in response to the presence of acidic chyme. It acts on the stomach to inhibit gastric acid secretion, which helps to regulate the pH balance in the digestive system. This hormone plays a crucial role in maintaining the proper functioning of the digestive system by preventing excessive acid production in the stomach.
11.
The circular layer of smooth muscle that lies between the stomach and the small intestine is called what?
Correct Answer
A. Pyloric spHincter
Explanation
The circular layer of smooth muscle that lies between the stomach and the small intestine is called the pyloric sphincter. This muscle acts as a valve, controlling the flow of partially digested food from the stomach into the small intestine. It helps regulate the release of food into the small intestine in a controlled manner, allowing for proper digestion and absorption of nutrients. The pyloric sphincter prevents the backflow of partially digested food from the small intestine back into the stomach, ensuring that the food moves through the digestive system in the correct direction.
12.
Where in the gastrointestinal tract is food digested and absorbed?
Correct Answer
B. Jejunum and ileum
Explanation
The jejunum and ileum are segments of the small intestine, where most of the digestion and absorption of nutrients from food occurs. The stomach primarily acts as a storage and mixing chamber for food, while the colon is responsible for reabsorbing water and electrolytes from undigested food. Therefore, the jejunum and ileum are the correct answer as they are the main sites of digestion and absorption in the gastrointestinal tract.
13.
Some smooth muscle cells in the gastrointestinal tract serve as pacemakers. They display rhythmic spontaneous oscillations in membrane potentials. What are these called?
Correct Answer
C. Slow waves
Explanation
Smooth muscle cells in the gastrointestinal tract that serve as pacemakers display rhythmic spontaneous oscillations in membrane potentials, which are known as slow waves. These slow waves help coordinate the contractions of the gastrointestinal muscles, allowing for the movement of food through the digestive system. Peristalsis refers to the coordinated muscular contractions that propel food through the digestive tract, while intestinal spasms and rapid contractility do not specifically refer to the rhythmic oscillations in membrane potentials seen in pacemaker cells.
14.
Defecation is controlled by both an internal and an external sphincter. What nerve controls the external sphincter?
Correct Answer
D. Pudendal nerve
Explanation
The pudendal nerve controls the external sphincter. The external sphincter is responsible for voluntary control of defecation, allowing us to hold or release stool as needed. The pudendal nerve innervates the muscles of the pelvic floor, including the external sphincter, and provides motor control to these muscles.
15.
The stomach secretes two important hormones in the gastrointestinal tract. One is gastrin. What is the second hormone secreted by the stomach?
Correct Answer
A. Ghrelin
Explanation
Ghrelin is the second hormone secreted by the stomach. It is primarily known for its role in stimulating appetite and regulating energy balance. Ghrelin is released when the stomach is empty and signals the brain to increase hunger and food intake. It also promotes the release of growth hormone and plays a role in regulating glucose metabolism.
16.
Saliva has more that one function. What are the functions of saliva? Mark all that apply.
Correct Answer(s)
A. Protection
B. Lubrication
C. Antibacterial
D. Initiate digestion of starches
Explanation
Saliva serves multiple functions in the body. It acts as a protective barrier, helping to prevent damage and infection in the mouth. Saliva also provides lubrication, aiding in the swallowing and digestion process. It has antibacterial properties, helping to control the growth of harmful bacteria in the mouth. Additionally, saliva contains enzymes that initiate the digestion of starches, breaking them down into simpler sugars. Therefore, the functions of saliva include protection, lubrication, antibacterial action, and initiation of starch digestion.
17.
The colon is home to between 300 and 500 different species of bacteria. What is their main metabolic function?
Correct Answer
B. Fermentation of undigestible dietary residue
Explanation
The colon is home to a diverse range of bacteria, and their main metabolic function is the fermentation of undigestible dietary residue. This process helps break down complex carbohydrates and fiber that cannot be digested by the human body. Through fermentation, these bacteria produce short-chain fatty acids, which provide energy for the colon cells and have various health benefits. This metabolic function is crucial for maintaining a healthy digestive system.
18.
Absorption is a major function of the gastrointestinal (GI) tract. How is absorption accomplished in the GI tract?
Correct Answer
C. Active transport and diffusion
Explanation
Absorption in the gastrointestinal (GI) tract is accomplished through active transport and diffusion. Active transport refers to the movement of molecules against their concentration gradient, requiring energy. This process allows the GI tract to absorb nutrients such as glucose and amino acids. On the other hand, diffusion is the passive movement of molecules from an area of higher concentration to an area of lower concentration. This process allows the GI tract to absorb molecules such as water, vitamins, and minerals. Together, active transport and diffusion ensure efficient absorption of nutrients and other substances in the GI tract.
19.
Nausea and vomiting can be side effects of many drugs as well as physiologic disturbances within the body. What is a common cause of nausea?
Correct Answer
D. Distention of the duodenum
Explanation
Distention of the duodenum can be a common cause of nausea. The duodenum is the first part of the small intestine, located just below the stomach. When it becomes distended or stretched due to various reasons such as an obstruction or blockage, it can trigger the sensation of nausea and lead to vomiting. This can occur as a result of certain medical conditions or even as a side effect of medications that affect the gastrointestinal system.
20.
Several neurotransmitters have been identified with nausea and vomiting. In this capacity, they act as neuromediators. What neuromediator is believed to be involved in the nausea and vomiting that accompanies chemotherapy?
Correct Answer
D. Opioid receptors
Explanation
Opioid receptors are believed to be involved in the nausea and vomiting that accompanies chemotherapy. Opioid receptors are found in the brain and gastrointestinal tract and play a role in regulating nausea and vomiting. Activation of these receptors by certain chemicals, such as opioids or endorphins, can lead to nausea and vomiting. This is why medications that block opioid receptors, such as ondansetron, are commonly used to prevent and treat chemotherapy-induced nausea and vomiting.
21.
The major physiologic function of the gastrointestinal system is to digest food and absorb nutrients into the bloodstream.
Correct Answer
A. True
Explanation
The gastrointestinal system plays a crucial role in the digestion and absorption of food. It breaks down food into smaller molecules through mechanical and chemical processes, such as chewing and the release of digestive enzymes. These smaller molecules are then absorbed into the bloodstream through the lining of the gastrointestinal tract. This allows the nutrients to be distributed throughout the body and used for energy, growth, and repair. Therefore, the statement that the major physiologic function of the gastrointestinal system is to digest food and absorb nutrients into the bloodstream is true.
22.
The lower esophageal sphincter, the ____________, lies just above the area where the esophagus joins the stomach.
Correct Answer
B. GastroesopHageal spHincter
Explanation
The correct answer is gastroesophageal sphincter. This is because the question is asking for the name of the sphincter that lies just above the area where the esophagus joins the stomach. The lower esophageal sphincter is also known as the gastroesophageal sphincter, so it is the correct answer. The other options (pharyngoesophageal sphincter, stomach, jejunum) are not located in the specified area.
23.
The _______ lies in the left side of the abdomen and serves as a food storage reservoir during the early stages of digestion.
Correct Answer
C. Stomach
Explanation
The stomach is located on the left side of the abdomen and acts as a food storage reservoir during the initial stages of digestion. It receives food from the esophagus and breaks it down further using stomach acid and enzymes. This allows for the absorption of nutrients and the passage of food into the small intestine for further digestion and absorption. The pharyngoesophageal sphincter and gastroesophageal sphincter are not responsible for food storage, and the jejunum is a part of the small intestine, not the stomach.
24.
The small intestine, which forms the middle portion of the digestive tract, consists of three subdivisions: the __________, __________, and ___________.
Correct Answer(s)
B. Duodenum
C. Jejunum
D. Ileum
Explanation
The small intestine is divided into three sections: the duodenum, jejunum, and ileum. The duodenum is the first part of the small intestine and receives partially digested food from the stomach. The jejunum is the middle section and is responsible for absorbing nutrients from the digested food. The ileum is the final section and absorbs any remaining nutrients, as well as vitamins and bile salts. These three subdivisions work together to ensure the proper digestion and absorption of nutrients in the small intestine.
25.
The _____________ carry out the secretory and absorptive functions of the gastrointestinal tract, and they produce the mucus that lubricates and protects the inner surface of the alimentary canal.
Correct Answer
A. Epithelial cells
Explanation
Epithelial cells carry out the secretory and absorptive functions of the gastrointestinal tract, meaning they are responsible for the secretion and absorption of substances in the digestive system. They also produce mucus, which lubricates and protects the inner surface of the alimentary canal. Epithelial cells line the entire digestive tract and play a crucial role in maintaining its proper functioning. They form a barrier that helps prevent the entry of harmful substances into the body and facilitate the absorption of nutrients from the digested food.
26.
______________ forms a moist and slippery surface that prevents friction between continuously moving abdominal structures.
Correct Answer
B. Serous fluid
Explanation
Serous fluid forms a moist and slippery surface that prevents friction between continuously moving abdominal structures. This fluid is secreted by serous membranes, which line the abdominal cavity and cover the organs within it. The serous fluid acts as a lubricant, reducing friction and allowing smooth movement of organs such as the intestines. This helps to prevent damage and irritation to the abdominal structures during movements such as digestion or peristalsis.
27.
The _________ contains blood vessels, nerves, and lymphatic vessels that supply the intestinal wall.
Correct Answer
C. Mesentery
Explanation
The mesentery is a fold of tissue that attaches the intestines to the abdominal wall. It contains blood vessels, nerves, and lymphatic vessels that supply the intestinal wall. This allows for the transport of nutrients and waste products, as well as the regulation of immune responses and nerve signals in the intestines.
28.
Like the self-excitable cardiac muscle cells in the heart, some smooth muscle cells of the gastrointestinal tract function as ____________.
Correct Answer
D. Pacemaker cells
Explanation
Some smooth muscle cells in the gastrointestinal tract function as pacemaker cells, similar to the self-excitable cardiac muscle cells in the heart. These pacemaker cells generate electrical impulses that coordinate the contraction and relaxation of the smooth muscle, allowing for the rhythmic movement of food through the digestive system. This rhythmic contraction and relaxation is essential for proper digestion and absorption of nutrients.
29.
The ________ nervous system consists of the myenteric and submucosal plexuses in the wall of the gastrointestinal tract.
Correct Answer
enteric
Explanation
The myenteric and submucosal plexuses are located in the wall of the gastrointestinal tract and are part of the enteric nervous system. This system is responsible for regulating the movements and secretions of the digestive system, independently from the central nervous system. It controls various functions such as peristalsis, secretion of enzymes and hormones, and blood flow to the digestive organs. Therefore, the correct answer is "enteric."
30.
_______________ monitor the stretch and distention of the gastrointestinal tract wall.
Correct Answer
A. Mechanoreceptors
Explanation
Mechanoreceptors are sensory receptors that respond to mechanical stimuli such as pressure, stretch, and vibration. In the context of the gastrointestinal tract, mechanoreceptors are responsible for monitoring the stretch and distention of the gastrointestinal tract wall. These receptors detect changes in the size and shape of the tract, allowing the body to regulate processes such as digestion and peristalsis. By detecting the mechanical stimuli, mechanoreceptors provide important feedback to the nervous system, helping to maintain proper functioning of the gastrointestinal system.
31.
___________ monitor the chemical composition of the gastrointestinal tract contents.
Correct Answer
B. Chemoreceptors
Explanation
Chemoreceptors monitor the chemical composition of the gastrointestinal tract contents. These receptors are specialized sensory cells that are sensitive to specific chemicals and can detect changes in their concentration. In the context of the gastrointestinal tract, chemoreceptors play a crucial role in detecting the presence of various substances such as nutrients, toxins, and hormones. They provide important feedback to the body, helping regulate processes like digestion and absorption of nutrients. By monitoring the chemical composition, chemoreceptors help maintain homeostasis and ensure proper functioning of the gastrointestinal system.
32.
Numerous vasovagal reflexes influence motility and secretions of the digestive tract.
Correct Answer
A. True
Explanation
The statement is true because the vasovagal reflex, which involves the vagus nerve, plays a significant role in regulating the motility and secretions of the digestive tract. The vagus nerve helps stimulate the release of digestive enzymes, increases intestinal contractions, and promotes the movement of food through the digestive system. Additionally, the vasovagal reflex can also cause a decrease in blood pressure and heart rate, leading to fainting or syncope, which can be triggered by certain gastrointestinal stimuli.
33.
Swallowing consists of three phases in the following order: an oral phase, an esophageal phase, and a pharyngeal phase.
Correct Answer
B. False
Explanation
The correct order is:
1. Oral phase
2. Pharyngeal phase
3. Esophageal phase
34.
The large intestine is the major site for the digestion and absorption of food.
Correct Answer
B. False
Explanation
The SMALL INTESTINE is the major site for the digestion and absorption of food.
35.
Defecation is normally initiated by the mass movements of the _________ intestine
Correct Answer
large
Large
Explanation
The correct answer is "large, Large" because defecation is typically initiated by the mass movements of the large intestine. The large intestine is responsible for absorbing water and electrolytes from the remaining indigestible food, forming solid waste known as feces. When the feces accumulate and stretch the walls of the large intestine, it triggers the urge to defecate. Therefore, the large intestine plays a crucial role in the process of elimination.
36.
The primary function of ________ is the stimulation of gastric acid secretion
Correct Answer
A. Gastrin
Explanation
Gastrin is a hormone that plays a crucial role in stimulating the secretion of gastric acid in the stomach. It is produced by specialized cells in the stomach lining called G cells. When food enters the stomach, gastrin is released and it acts on parietal cells in the stomach lining to increase the production and release of gastric acid. This acid helps in the digestion of food and the breakdown of proteins. Therefore, the primary function of gastrin is to stimulate gastric acid secretion.
37.
G cells secrete ________.
Correct Answer
A. Gastrin
Explanation
Gastrin is secreted by G cells. It is a hormone that stimulates the release of gastric acid in the stomach. Gastrin also promotes the growth of gastric mucosa and increases gastric motility.
38.
___________ has potent growth hormone releasing activity and has a stimulatory effect on food intake and digestive function, while reducing energy expenditure.
Correct Answer
B. Ghrelin
Explanation
Ghrelin is a hormone that has potent growth hormone releasing activity. It also stimulates food intake and digestive function, while reducing energy expenditure.
39.
__________ potentiates the action of secretin, increasing the pancreatic bicarbonate response to low circulating levels of secretin.
Correct Answer
C. Cholecystokinin
Explanation
Cholecystokinin potentiates the action of secretin, increasing the pancreatic bicarbonate response to low circulating levels of secretin. This means that when cholecystokinin is present, it enhances the effect of secretin on the pancreas, causing it to release more bicarbonate. This is important because bicarbonate helps to neutralize stomach acid, and the increased release of bicarbonate can help to maintain the pH balance in the digestive system.
40.
___________ stimulates biliary secretion of fluid and bicarbonate.
Correct Answer
C. Cholecystokinin
Explanation
Cholecystokinin is a hormone that stimulates the secretion of fluid and bicarbonate in the bile. Bile is produced by the liver and stored in the gallbladder, and it plays a crucial role in the digestion and absorption of fats. Cholecystokinin is released in response to the presence of fatty acids and amino acids in the small intestine. It acts on the gallbladder to cause it to contract and release bile into the small intestine, and it also stimulates the secretion of bicarbonate from the pancreas. This helps to neutralize the acidic chyme that enters the small intestine from the stomach, creating a more favorable environment for digestion and absorption.
41.
_________ regulates gallbladder contraction and gastric emptying.
Correct Answer
C. Cholecystokinin
Explanation
Cholecystokinin is a hormone that regulates gallbladder contraction and gastric emptying. When food enters the duodenum, cholecystokinin is released by the small intestine and acts on the gallbladder to stimulate the release of bile, which helps in the digestion and absorption of fats. Cholecystokinin also acts on the stomach to slow down gastric emptying, allowing for proper digestion and absorption of nutrients. Therefore, cholecystokinin plays a crucial role in the regulation of gallbladder contraction and gastric emptying.
42.
The ___________ secrete hydrochloric acid and intrinsic factor, which is necessary for the absorption of vitamin B12.
Correct Answer
D. Parietal cells
Explanation
Parietal cells secrete hydrochloric acid and intrinsic factor, which is necessary for the absorption of vitamin B12.
43.
The _________ secrete pepsinogen, an enzyme that initiates proteolysis or breakdown of proteins.
Correct Answer
F. Chief cells
Explanation
Chief cells secrete pepsinogen, an enzyme that initiates the breakdown of proteins. Pepsinogen is converted into pepsin in the presence of hydrochloric acid in the stomach. Pepsin is then responsible for further breaking down proteins into smaller peptides. Therefore, it is the chief cells that play a crucial role in the initial digestion of proteins in the stomach.
44.
Chief cells secrete _________, an enzyme that initiate proteolysis or breakdown of proteins.
Correct Answer
E. Pepsinogen
Explanation
Pepsinogen is the correct answer because it is an enzyme secreted by chief cells in the stomach. Pepsinogen is the inactive form of pepsin, which is responsible for the breakdown of proteins into smaller peptides. Once pepsinogen is released into the stomach, it is activated by the acidic environment and converted into pepsin, which then starts the process of proteolysis.
45.
__________ secrete large amounts of alkaline mucus that protect the duodenum from the acid content in the gastric chyme and from the action of the digestive enzymes.
Correct Answer
G. Brunner glands
Explanation
Brunner glands secrete large amounts of alkaline mucus that protect the duodenum from the acid content in the gastric chyme and from the action of the digestive enzymes.
46.
_________ is the process of dismantling foods into their constituent parts.
Correct Answer
digestion
Digestion
Explanation
Digestion is the process of breaking down food into smaller, simpler molecules that can be absorbed and used by the body. It involves both mechanical and chemical processes, such as chewing, stomach contractions, and the action of enzymes. Through digestion, complex carbohydrates are broken down into simple sugars, proteins are broken down into amino acids, and fats are broken down into fatty acids and glycerol. These smaller molecules can then be absorbed into the bloodstream and transported to cells where they are used for energy, growth, and repair.
47.
__________ is the process of moving nutrients and other materials from the external environment of the gastrointestinal tract to the internal environment.
Correct Answer
absorption
Absorption
Explanation
Absorption is the process by which nutrients and other materials are transferred from the external environment of the gastrointestinal tract to the internal environment. This process allows the body to take in essential nutrients, such as vitamins, minerals, and carbohydrates, from the food we consume. Absorption occurs primarily in the small intestine, where nutrients are absorbed into the bloodstream and transported to various cells and tissues throughout the body to support growth, energy production, and overall physiological functions.
48.
Each villus is covered with cells called _______ that contribute to the absorptive and digestive functions of the small bowel and goblet cells that provide mucus.
Correct Answer
A. Enterocytes
Explanation
The correct answer is enterocytes. Enterocytes are cells that line the villi in the small intestine. They are responsible for absorbing nutrients from digested food and transporting them into the bloodstream. Additionally, enterocytes play a role in the digestion of carbohydrates and proteins. The presence of goblet cells on the villi also contributes to the secretion of mucus, which helps protect the intestinal lining and aids in the movement of food through the digestive tract.
49.
The enterocytes secrete ____________ that adhere to the border of the villus structures.
Correct Answer
B. Brush border enzymes
Explanation
Enterocytes are specialized cells in the lining of the small intestine that are responsible for absorbing nutrients from digested food. They have microvilli on their surface, which are finger-like projections that increase their surface area for absorption. These microvilli are covered with brush border enzymes, which are enzymes that help break down complex molecules into smaller, more easily absorbed molecules. These enzymes adhere to the border of the villus structures, further enhancing the absorption process.
50.
Triglycerides are broken down by pancreatic ________.
Correct Answer
C. Lipase
Explanation
Triglycerides, which are a type of fat molecule, are broken down by an enzyme called lipase. Lipase is produced by the pancreas and helps to break down triglycerides into fatty acids and glycerol. This process occurs in the small intestine, where lipase is released and acts on the triglycerides present in the food we consume. The breakdown of triglycerides allows for the absorption of fatty acids and glycerol into the bloodstream for energy production and storage.