Exam 4 & 5 Canvas Quizzes

3. Which of the following statements about the fat digestion and absorption is/are FALSE? a. Triglycerides are cleaved by bile salts b. Triglycerides are digested by pancreatic lipase into free fatty acids and monoglycerides c. Free fatty acids, monoglycerides and bile salts form chylomicrons in the lumen of the small intestine d. After absorbed by enterocytes, the free fatty acids and glycerol are repacked into triglycerides and these, together with cholesterol and proteins form micelles that are exocytosed and enter lacteals

A: pancreatic enzymes cleave triglycerides C: these 3 are called micelles (chylomicrons= triglycerides & proteins) D: chylomicrons are exocytosed and enter lacteals

4. Which of the following statements about the intestinal wall is/are FALSE? a. Due to the presence of circular folds, villi and microvilli, the absoptive area of the intestinal wall in humans is approximately 200 square meters. b. Villi are small, finger-like mucosal protrusions, which are covered by enterocytes and by goblet (mucus secreting) cells. The lamina propria of a villus contains blood capilaries and a lacteal. c. The surface of microvilli is covered by enterocytes. d. The life expectancy of enterocytes is about 3 days. They are replaced by new cells that originate from the crypt stem cells.

C. *microvilli are covered by enterocytes, goblet cells, enteroendocrine cells, and Paneth cells*

which of the following Is not true about gastric HCl function and its secretion? a. HCl activates pepsinogen b. HCl secretion is stimulated by gastrin c. HCl kills microbes in the stomach d. HCl is secreted from chief cells

D. *it is secreted by parietal cells*

which of the following is NOT secreted by gastric gland? a. secretin b. HCl c. pepsinogen d. mucus

a. secretin > *secreted by duodenum*

3. Which of the following statements about the small intestine is/are FALSE a. The duodenum receives the chyme from the stomach. It also receives secretions from the pancreas, liver and gall bladder b. Most of chemical digestion and absorption happens in the ileum c. Jejunum is the longest segment of the small intestine in humans. In other animals, it is a short segment that connects the small intestine to the large intestine

b. *happens in the jejunum* c. *ileum is the longest segment of the small intestine in humans*

5. Which of the following statements about defecation in humans is/are FALSE? a. The defecation is typically triggered by enteric sensory neurons that sense stretching of the rectal wall when feces are pushed by the mass movements of the colon in the rectum b. When the rectum fills with feces, the sensory enteric neurons activate the external anal sphincter c. The sensory neurons activate the parasympathetic preganglionic neurons that activate the enteric motor neurons in the muscularis externa of the rectal wall d. The parasympathetic motor neurons activate peristalsis of rectum and relax the internal anal sphincter

b. *only when it is convenient to poop, then voluntary motor neurons are inhibited allowing the external anal sphincter to relax so feces my pass*

1. Which of the following statement about the digestive system is FALSE? a. The digestion occurs in the lumen of alimentary tract as a consequence of mechanical, chemical, enzymatic and fermentative processing of food b. Most of the organic nutrients in food can be absorbed without any additional processing in the alimentary canal c. The process of decomposing food into absorbable components is called digestion. d. The digestive system, a.k.a.the gastro-intestinal system, consists of the alimentary canal and several accessory organs

b. Most of the organic nutrients in food can be absorbed without any additional processing in the alimentary canal

1. Which of the following statements about the secondary active transport in enterocytes is FALSE? a. Glucose, amino acids, some di- and tri-peptides, bile salts and B vitamines enter enterocytes with the help of the secondary active transport b. The secondary active transport is powered directly by the ATP c. The secondary active transport in enterocytes is powered by the concentration gradient of sodium cations d. The sodium concentration gradient is maintained by sodium/potassium pumps

b. The secondary active transport is powered directly by the ATP

which of the following is not true about the phases of gastric activity? a. the cephalic phase can be triggered by smell of food b. during the esophageal phase the secretion of gastric juices is inhibited c. during the gastric phase secretion of gastric juices increases d. the intestinal phase is characterized by controlled gastric empying

b. during the esophageal phase the secretion of gastric juices is inhibited > *there is no esophageal phase in the phases of gastric activity*

2. Which of the following statements about nutrient digestion and absorption is FALSE? a. Proteins are cleaved down to amino acids, which are then absorbed and enter blood capillaries b. Carbohydrates are cleaved down to monosacharides, absorbed, and then they enter blood capillaries c. Fats are broken down to free fatty acids and monoglycerides, which are then absorbed and enter blood capillaries d. Nutrients are enzymatically digested and their cleavage products are absorbed into blood or lymphatic vessels

c. Fats are broken down to free fatty acids and monoglycerides, which are then absorbed and enter blood capillaries

1. Which of the following statements about the enteric nervous system is/are FALSE? a. Neurons in the submucosal and myenteric plexuses form the enteric nervous system which controls intestinal secretory activity and also contractions of the smooth muscles in the alimentary canal wall b. Short reflexes contain sensory neurons, interneurons and motor neurons, which are all located in the alimentary canal wall. These reflexes control activity that is restricted to a particular part of the alimentary canal c. Long reflexes don't include neurons residing in the wall of the alimentary canal. They rely on neurons that are located exclusively in the central nervous system d. Long reflexes can be initiated by the visual information and they can control the activity of salivary glands

c. Long reflexes don't include neurons residing in the wall of the alimentary canal. They rely on neurons that are located exclusively in the central nervous system

which of the following is not the function of the stomach a. temporary storage of food b. mechanical digestion of food c. absorption of amino acids d. chemical digestion by hydrochloric acid and enzymes

c. absorption of amino acids

2. Which of the following is/are NOT a part of the large intestine a. Cecum b. Rectum c. Haustra d. Duodenum e. Anal canal f. Pyloric sphincter

d. duodenum f. pyloric sphincter

2. Contractions of smooth muscles in the muscularis externa mix digesta and propel digesta down the alimentary canal. These muscles generate two contraction patterns - segmentation and peristalsis. Peristalsis mixes intestinal contents. Segmentation propels digesta down the alimentary canal. a. True b. False

false

3. Carnivores have typically much larger large intestine than hind gut fermenting herbivores a. True b. False

false

1. The function of the large intestine is to reabsorb water and absorb vitamins and volatile fatty acids that are produced by bacteria that ferment undigested carbohydrates. The large intestine also compacts digesta into feces and stores and expels the feces. a. True b. False

true

1. The primary functions of the small intestine are the final digestion of food and the absorption of nutrients a. True b. False

true

2. Glucose and galactose enter enterocytes via sodium co-transporter. Fructose enters enterocytes by facilitated diffusion. All these monosaccharides leave enterocytes via a glucose transporter GLUT 2. a. True b. False

true

3. Gastrin is secreted by stomach in response to peptides and amino acids in the gastric lumen. This hormone stimulates the HCl production by the stomach. Secretin is secreted by duodenum in responses to a low pH. It smulates the release of bicarbonate by pancreas. a. True b. False

true

4. Amino acids diffuse outside of the enterocyte via facilitated diffusion. Once outside, they diffuse through inter-cellular clefts in the capillary blood. a. True b. False

true

4. When processing its contents, the large intestine exhibits segmentation, peristalsis, antiperistalsis and mass movements. The mass movements in humans happen 3-4 times per day and they are triggered by the gastrocolic reflex. a. True b. False

true

5. Hepatocytes in the liver secrete bile into a system of ducts that empty into the common bile duct. When this duct's sphincter is closed, the bile backs up and accumulates in the gall bladder. Walls of the gall bladder can contract and expel the bile if needed. The vagus nerve and the enteric hormone CCK stimulate the gall bladder contraction. a. True b. False

true

5. During absorption of nutients, the osmolarity of the extracellular fluid that surrounds the basolateral membrane of enterocytes increases. This drives the reabsorption of water from the lumen to the interstitium. a. True b. False

true lumen > apical side > enterocyte > basolateral side > extracellular space > blood vessel