Chapter 25. The Digestive System Part 2 (Sections 4-7) Homework Assignment

Complete each sentence by dragging the proper label into the appropriate position. Then, rearrange the sentences into a logical order of digestive processes.

A zymogen is an inactive or pro-enzyme that is only activated after it has been secreted and had some of its amino acids cleaved. The chief cells of the stomach secrete pepsinogen into the stomach lumen; which in the presence of HCl becomes pepsin, the active form of the enzyme. The pancreas produces a number of zymogens that are released in the GI tract at the duodenum including procarboxypeptidase, chymotrypsinogen, and trypsinogen. After contacting the intestinal enzyme enteropeptidase, trypsinogen is converted into trypsin. Trypsin then works on converting both chymotrypsinogen and procarboxypeptidase into chymotrypsin and carboxypeptidase, respectively.

Defecation is stimulated by __________ and __________ reflexes.

parasympathetic; local

Correctly label the following parts of the large intestine.

sssssssssss

Mass movements of the colon occur __________ times per day.

1 to 3

Drag each label into the appropriate position in order to identify where each secretion enters the GI tract.

Buccal cavity: salivary amylase, lingual lipase Duodenum: bile, chymotrypsinogen, pancreatic lipase, ribonuclease, deoxyribonuclease Stomach: pepsinogen, HCl, intrinsic factory

How does sucrose change the configuration of sucrase?

By binding to the active site

Drag each label into the appropriate position in order to identify which type of macromolecule is the target of each digestive enzyme or compound.

Carbohydrate: pancreatic amylase, dextrinase, glucoamylase, lactase Lipid: bile salts, lecithin Protein: HCl, trypsin, dipeptidase, aminopeptidase

Drag each label into the appropriate position in order to identify which type of macromolecule is the target of each digestive enzyme or compound.

Carbohydrate: salivary amylase, maltase, sucrase Lipid: lingual lipase, pancreatic lipase, gastric lipase Protein: pepsin, chymotrypsin, carboxypeptidase

Read each of the scenarios below. Then, click and drag them into the appropriate category to identify whether it describes the actions of secretin or cholecystokinin.

Cholecystokinin: - Secreted in response to fats in the small intestine - Strong stimulatory effect on the gallbladder - Eventually leads to the emulsification of lipid globules - Stimulates the secretion of pancreatic amylase and pancreatic lipase - Relaxes the sphincter of the hepatopancreatic ampulla - Stimulates bile release into the duodenum Secretin: - Secreted in response to chyme's low pH - Results in sodium bicarbonate release by the liver and pancreas - Ultimately protects the intestinal wall from HCl - Helps flush pancreatic enzymes into the duodenum

Click and drag the appropriate word or phrase from the left to complete the sentences on the right.

Contractions of the small intestine have three functions: mix chyme with digestive juices, allow for contact digestion with the brush border, and move contents toward the lumen of the large intestine. The process of segmentation consists of muscular contractions whose effect is to knead and churn the contents. As segmentation declines, peristalsis begins in the duodenum. Successive peristaltic waves of contraction overlap with each other, called the migrating motor complex. The gastroileal reflex enhances segmentation in the ileum and relaxes the ileal papilla, allowing contents to enter the cecum.

Identify each organ pictured below. Then, click and drag each characteristic listed to the appropriate organ to which it pertains.

Large intestine: no folds or villi, haustra, location of flatus, mass peristalsis, taenia coli, prepares waste for removal, greater density of goblet cells Small intestine: microvilli, maximized absorption of nutrients, circular folds

Identify each image shown below. Then, click and drag each word or phrase into the appropriate category to identify the organ to which it pertains.

Liver: Synthesizes bile Synthesizes bile acids Releases its secretion into the bile canaliculi Gallbladder: Stores the substance that breaks globules of fat into droplets Contraction is induced by cholecystokinin Pancreas: Secretes inactive enzymes that, when activated, will digest proteins Secretes zymogen Secretes enzymes that digest fats Secretes deoxyribonuclease Secretes an enzyme that digests carbohydrates

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

Many times

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.;\ food; stomach chyme; duodenum

Identify each organ pictured below. Then, click and drag each characteristic listed into the appropriate category to identify the organ to which it pertains.

Stomach: rugae, gastric pits, oblique layer in muscularis, maximized size for storage and mixing Small intestine: plicae, villi, brush border, maximized surface are for absorption, microvilli, aggregated lymphoid nodules

Which of the following statements is true regarding sucrase?

Sucrase breaks sucrose into glucose and fructose.

Complete each sentence by dragging the proper label into the appropriate position.

The absorption of carbohydrates from the intestinal lumen occurs directly through secondary active transport. Sodium-potassium pumps in the basal membrane work to actively transport sodium out of the cell towards the interstitium, while cotransporting potassium to the intracellular fluid. With a declining intracellular concentration of sodium, sodium now diffuses from the intestinal lumen to the ICF of the epithelium. The luminal diffusion of sodium to the ICF is coupled with glucose, and galactose cotransport into the cell.

Place a single word into each sentence to make it correct, then arrange each sentence into a logical paragraph order to explain protein digestion and absorption.

The act of protein digestion begins in the mouth with mechanical digestion. Once in the stomach, pepsin hydrolyzes peptide bonds. Then, in the small intestine, trypsin, chymotrypsin and carboxypeptidase continue the breakdown of proteins. The brush border of the small intestine will finish the breakdown and begin absorption.

Place a single word into each sentence to make it correct, then arrange the sentences to accurately describe the process of starch digestion from beginning to end.

The entire process of starch digestion begins in the mouth with amylase. Amylase digests starch first into oligosaccharides, which are up to eight glucose residues long. Oligosaccharides are catabolized into maltose, which is a disaccharide. Maltose is then converted into glucose, which can be absorbed by the small intestine.

Complete each sentence by dragging the proper label into the appropriate position. Then, rearrange the sentences in order from proximal to distal through the digestive tract.

The first sphincter of the digestive system, called the orbicularis oris muscle, surrounds the entrance to the oral cavity. The upper esophageal sphincter separates the pharynx from the esophagus and regulates the passage of food into the esophagus. At the terminal end of the esophagus is the lower esophageal sphincter, which subconsciously controls the entrance of food into the stomach. The pyloric sphincter regulates the movement of food from the stomach to the small intestine. The junction of the small and large intestines is marked by a pronounced muscular swelling known as the ileal papilla, which regulates movement into the large intestine. The involuntarily controlled internal anal sphincter is composed of smooth muscle that relaxes at the onset of defecation. The final step in allowing defecation is voluntary relaxation of the external anal sphincter, which is composed of skeletal muscle.

Complete each sentence by dragging the proper label into the appropriate position.

Three main vessels make up the hepatic triad. These include the hepatic portal vein, hepatic artery, and bile ductules. Blood arrives at the liver through both the hepatic portal vein and the hepatic artery, although the hepatic portal vein delivers nutrient rich, oxygen poor blood to the liver cells. The hepatic artery is responsible for delivering oxygen rich blood to the hepatocytes and thus providing for the large metabolic demand for this tissue. The bile ductules collect bile produced in the hepatic lobules and deliver it to the hepatic ducts on their way to the gallbladder for storage.

T/F: Defecation reflexes are stimulated by the presence of feces in the rectum.

True

T/F: Mass movements of the colon propel its contents toward the rectum.

True

Place a single word into each sentence to make it correct, then arrange each sentence into a logical paragraph order describing the activation of pancreatic enzymes.

When stimulated, the pancreas will secrete trypsinogen. The duodenum, in turn, will secrete enteropeptidase, which will convert trypsinogen intro trypsin. Trypsin will digest dietary proteins and also catalyzes the conversion of more trypsinogen into trypsin. Finally, trypsin will also activate two other pancreatic zymogens, called chymotrypsinogen and procarboxypeptidase.