Chapter 25: Digestion

Which of the following is a function of the bacterial flora? Check all that apply. - Bacteria digest cellulose. - Bacteria synthesize vitamin C. - Bacteria synthesize vitamin K. - Bacteria produce most of our intestinal gas. - Bacteria secrete extra mucus to lubricate the intestinal walls for defecation.

- Bacteria digest cellulose. - Bacteria synthesize vitamin K.

Which of the following statements is true regarding the absorption of nutrients? Check all that apply. - 80% of the sugar absorbed is fructose. - Carbohydrates are absorbed as monosaccharides. - Proteins can only be absorbed as amino acids. - Proteins can be absorbed as disaccharides. - Micelles are required for lipid absorption.

- Carbohydrates are absorbed as monosaccharides. - Micelles are required for lipid absorption.

Which of the following statements is/are true regarding the regulation of digestive secretions? Check all that apply. - Pancreatic enzymes are under both neural and hormonal control. - Cholecystokinin is released by the gallbladder. - Secretin induces gallbladder contraction. - CCK is released in response to a low pH in the duodenum. - Via the vagus nerve, acetylcholine stimulates the pancreatic acini.

- Pancreatic enzymes are under both neural and hormonal control. - Via the vagus nerve, acetylcholine stimulates the pancreatic acini.

Which of the following is a method of motility in the small intestine? Check all that apply. - Haustral churning - Mass movement - Segmentation - Peristalsis - Migrating motor complex

- Segmentation - Peristalsis - Migrating motor complex

Which of the following statements is true regarding the anatomy of the colon and/or small intestine? Check all that apply. - The colon and the small intestine both have intestinal crypts. - The small intestine and the colon both utilize peristalsis to propel contents. - The small intestine and the colon both display haustra in their anatomical structure. - The small intestine and the colon both have circular and longitudinal muscles in the muscularis. - The small intestine has goblet cells while the colon does not.

- The colon and the small intestine both have intestinal crypts. - The small intestine and the colon both utilize peristalsis to propel contents. - The small intestine and the colon both have circular and longitudinal muscles in the muscularis.

Which of the following statements is true regarding the neural control of defecation? Check all that apply. - The intrinsic defecation reflex results in feces moving from the sigmoid colon to the rectum. - The intrinsic defecation reflex is voluntary. - The external anal sphincter is under voluntary control. - The parasympathetic defecation reflex helps relax the internal anal sphincter. - The internal anal sphincter is under voluntary control.

- The intrinsic defecation reflex results in feces moving from the sigmoid colon to the rectum. - The external anal sphincter is under voluntary control. - The parasympathetic defecation reflex helps relax the internal anal sphincter.

Which of the following statements is/are true regarding mechanical and/or chemical digestion? Check all that apply. - The muscular contractions of the stomach's muscularis layers contribute to mechanical digestion. - Pancreatic lipase contributes to mechanical digestion. - The emulsification of fats by bile is an example of chemical digestion. - The action of pepsin on proteins in the stomach is an example of chemical digestion. - The action of salivary amylase on food is an example of mechanical digestion.

- The muscular contractions of the stomach's muscularis layers contribute to mechanical digestion. - The action of pepsin on proteins in the stomach is an example of chemical digestion.

Which of the following statements is true regarding the swallowing reflex? Check all that apply. - The oral phase is voluntary, and the phayngoesophageal phase is involuntary. - The integrating center of the reflex is in the pons. - Four different cranial nerves carry the motor impulses of the reflex. - The oral phase is involuntary, and the phayngoesophageal phase is voluntary. - The vagus nerve is the only nerve that contributes to the reflex.

- The oral phase is voluntary, and the phayngoesophageal phase is involuntary. - Four different cranial nerves carry the motor impulses of the reflex.

Which of the following statements is/are true about gastric motility? Check all that apply. - The stomach uses the contraction of three layers of muscle to mix, churn, and propel its contents to the duodenum. - The stomach releases up to three liters of chyme to the duodenum at a time. - A typical meal is emptied from the stomach in approximately one hour. - When the pyloric sphincter is relaxed, chyme moves from the stomach to the duodenum. - The receptive-relaxation response of the stomach allows it to accommodate more food.

- The stomach uses the contraction of three layers of muscle to mix, churn, and propel its contents to the duodenum. - When the pyloric sphincter is relaxed, chyme moves from the stomach to the duodenum. - The receptive-relaxation response of the stomach allows it to accommodate more food.

Mass movements of the colon occur __________ times per day.

1 to 3

Complete each sentence by dragging the proper label into the appropriate position. 1. Three main vessels make up the ______________. These include the hepatic portal vein, hepatic artery, and bile ductules. 2. Blood arrives at the liver through both the hepatic portal vein and the hepatic artery, although the hepatic portal vein delivers nutrient rich, oxygen _________ blood to the liver cells. 3. The ______________ is responsible for delivering oxygen _________ blood to the hepatocytes and thus providing for the large metabolic demand for this tissue. 4. The _____________ collect bile produced in the hepatic lobules and deliver it to the hepatic ducts on their way to the ____________ for storage.

1. hepatic triad 2. poor 3. hepatic artery; rich 4. bile ductules; gallbladder

Which of the following occurs during the gastric phase of gastric secretion?

All of these take place in the gastric phase.

How does sucrose change the configuration of sucrase?

By binding to the active site

What is the mechanical and chemical breakdown of food called?

Digestion

Which of the following inhibits the secretion of the gastric glands?

Duodenal pH of less than two

What are the segments of the small intestine in the order through which food passes?

Duodenum, jejunum, ileum

What is the straight muscular tube conveying food from pharynx to the stomach called?

Esophagus

In which direction do the peristaltic contractions of the stomach's smooth muscle move contents?

From the body to the pyloric region

Which of the following hormones does not inhibit gastric gland secretions?

Gastrin

What are the microscopic structural subunits of the liver?

Hepatic lobules

Which of the following describes the fundus of the stomach?

It is the domed superior region.

How often can a sucrase molecule be used to hydrolyze sucrose?

Many times

Which of the following is a feature that the stomach and the small intestine have in common?

Mucus-secreting cells

Where is sucrase found in the human body?

On the microvilli of the small intestine

Mass movements in the colon are stimulated by the presence of __________ in the __________.

Only the first and second choices are correct.

Which organ is located behind the greater curvature of the stomach and acts as both an endocrine and exocrine gland?

Pancreas

Which of the following does not stimulate the secretion of HCl in the stomach?

Secretin

What is the outermost layer of the digestive tract wall?

Serosa

Which of the following statements is true regarding sucrase?

Sucrase breaks sucrose into glucose and fructose

Ion exchange molecules in the plasma membrane of the parietal cells exchange __________ ions going out for __________ ions coming in.

bicarbonate; chloride

In order for digestion to occur, chyme is required to contact the microvilli of the intestinal wall because the __________.

brush border enzymes are not secreted into the lumen

In the parietal cells, the enzyme carbonic anhydrase causes a reaction between __________ and __________.

carbon dioxide; water

Gastric secretion begins during the __________ phase and ends during the __________ phase.

cephalic; intestinal

The network of nerves that regulate digestive motility, secretion, and blood flow is called the __________ system.

enteric nervous

The hormone __________ stimulates the secretion of the enzyme __________ in the stomach.

gastrin; pepsinogen

Blood sugar refers to circulating levels of __________ in the blood.

glucose

Secretin is released from the duodenum in response to _________.

hydrochloric acid in chyme

Hydrochloric acid is formed when __________.

hydrogen ions and chloride ions join in the duct of the gastric gland

The peristaltic movement of colonic contents triggered by the gastrocolic reflex approximately 1-3 times per day is called __________.

mass movement

Defecation is stimulated by __________ and __________ reflexes.

parasympathetic; local

Stimulation from the __________ nervous system via the __________ nerve causes the secretion of HCl in the stomach.

parasympathetic; vagus

Which of the following enzymes is produced by the stomach?

pepsin