Chapter 25. The Digestive System

villi

1.

goblet cell

4.

Which hormone has a strong stimulatory effect on the gallbladder?

CCK

Which of the following statements is true regarding the sodium-glucose transport protein (SGLP)?

It transports glucose and sodium from the intestinal lumen into the epithelial cells.

The digestion of starch by amylase results in the production of which of the following?

Oligosaccharides and maltose

What are chylomicrons?

Particles that transport fats into lymph and blood

Which of the following is TRUE regarding peptic ulcers?

Peptic ulcers have been linked to Helicobacter pylori.

aminopeptidase

Takes off one amino acid from the amine side of a peptide chain.

Carboxypeptidase

Takes off one amino acids from the -COOH side of a peptide chain.

Activation of Pancreatic Enzymes: trypsin

The duodenum, in turn, will secrete enteropeptidase, which will convert trypsinogen into _______ ..

True or False: Salivary amylase is produced by the sublingual, submandibular, and parotid salivary glands.

True

True or False: The digestive system processes food, extracts nutrients, and eliminates the residue.

True

Activation of Pancreatic Enzymes: proteins

Trypsin will digest dietary _______ and also catalyzes the conversion of more trypsinogen into trypsin.

Activation of Pancreatic Enzymes: pancreas

When stimulated, the ______ will secrete trypsinogen.

Esophagus

Which structure is indicated in the picture?

Chylomicrons are made up of what molecules coated with phospholipids and protein?

fats

The hormone produced by enteroendocrine G cells that stimulates stomach HCl and enzyme activity is

gastrin

The primary function of the ______ intestine is to absorb water and electrolytes, but not other nutrients.

large

Enzymes that digest lipids are called

lipases

identify which type of macromolecule is the target of each digestive enzyme or compound: bile salts

lipid

identify which type of macromolecule is the target of each digestive enzyme or compound: lecithin

lipid

chemical or mechanical digestion: bolus formation

mechanical

chemical or mechanical digestion: churning

mechanical

chemical or mechanical digestion: haustral contractions

mechanical

chemical or mechanical digestion: peristalsis

mechanical

chemical or mechanical digestion: segmentation

mechanical

Droplets of fat products surrounded by bile acids are called what?

micelles

3. HCl will remove some amino acids from pepsinogen and turn it into ____________ .

pepsin

The inactive form of pepsin is

pepsinogen

What is the inactive precursor of pepsin?

pepsinogen

The esophagus is ______ to the trachea.

posterior

identify which type of macromolecule is the target of each digestive enzyme or compound: HCl

protein

identify which type of macromolecule is the target of each digestive enzyme or compound: aminopeptidase

protein

The ________ regulates the passage of bile and pancreatic juices into the duodenum.

sphincter of Oddi (hepatopancreatic sphincter)

The muscle tone of the __________ along the colon contracts it lengthwise, causing its walls to bulge and form pouches called __________.

taeniae coli; haustra

Following the digestion of lipids, FFA's and monoglycerides are transported into the endoplasmic reticulum and re-synthesized into which of the following?

triglycerides

True or false: After digestion and absorption into absorptive cells, fatty acids and monoglycerides are reassembled into triglycerides before being moved into the lymph.

true

What are the typical end products of triglyceride digestion?

two free fatty acids + monoglyceride

What are the functions of the large intestine?

water and electrolyte absorption

An enzyme that is secreted in its inactive form is known as a ______.

zymogen

The soupy mixture of semidigested food formed in the stomach is known as

chyme

What is the semi-liquid mixture of partially digested food within the stomach known as?

chyme

True or False: Absorption of many nutrients starts in the stomach.

False

True or False: Gastric juice consists entirely of water and hydrochloric acid.

False

True or false: The role of the liver in digestion is to produce digestive enzymes.

False

True or false: Secretin and cholecystokinin are gastric hormones.

False; secretin and cholecystokinin (CCK) primarily stimulate the pancreas and gallbladder

What is the hydrolysis of large dietary macromolecules into monomers known as?

chemical digestion

1. In the gastric gland, the _____cells secrete pepsinogen.

chief

Dipeptidase

Breaks apart the final two amino acids resulting from a former protein

lactase

Brush-border enzyme that is vital to the digestion of breast milk.

Which letter indicates the fundus?

C

Which cells produce secretin and cholecystokinin?

Duodenal enteroendocrine cells

________ is the forceful ejection of stomach (and sometimes duodenal) contents into the mouth.

Emesis

The enzyme that digests dietary starch is salivary or pancreatic

amylase

4. Pepsin will then be used in a(n) ____________ effect and aid in the conversion of more pepsinogen.

autocatalytic

Which letter indicates the greater curvature?

D

Activation of Pancreatic Enzymes: zymogens

Finally, trypsin will also activate two other pancreatic ________, called chymotrypsinogen and procarboxypeptidase.

protein digestion and absorption: mechanical

1. The act of protein digestion begins in the mouth with _____ digestion.

absorptive cell

2.

protein digestion and absorption: pepsin

2. Once in the stomach, ______ hydrolyzes peptide bonds.

brush border of microvilli

3.

protein digestion and absorption: carboxypeptidase

3. Then, in the small intestine, trypsin, chymotrypsin and _________ continue the breakdown of proteins.

protein digestion and absorption: brush border

4. The ____________ of the small intestine will finish the breakdown and begin absorption.

lacteal

5.

capillary network

6.

HCl

Acidic compound that activates pepsinogen

pepsin

Acidophilic enzyme that cleaves all peptide bonds between tyrosine and phenylalanine.

Choose all that are examples of mechanical digestion.

Churning of the small intestine Churning of the stomach Chewing

Each of the following lists some of the tissue layers of the digestive tract. Which one has them in correct order from lumen to external surface?

Mucosa, submucosa, muscularis externa, serosa

Salivary amylase is secreted into the oral cavity to aid in digestion. Once the food mixed with this enzyme is swallowed and enters the stomach, would you expect salivary amylase to continue to be as active in digestion in the stomach? Explain.

No, salivary amylase would not be as effective in the stomach. Salivary amylase functions best at pH 6.8 - 7. Once the food bolus is swallowed and met with gastric juice, the catabolic activity of salivary amylase stops due to the lower acidic pH of the stomach.

Which describes segmentation?

Non-migrating constrictions and relaxations along the intestine

What is the function of micelles?

To transport fats in the intestine to the surface of the enterocytes

Certain drugs designed to reduce blood cholesterol work by blocking the reabsorption of bile acids in the ileum. Explain why they would have this cholesterol lowering effect.

Too much cholesterol in your blood can cause a build up in your arteries and block them. Medicines that reduce blood cholesterol block the reabsorption of bile acids into the blood. This forces your body to use the available cholesterol to make more bile acid. This forced use of available cholesterol reduces the amount of cholesterol in your blood.

Of the following components of bile, only __________ has/have a digestive function.

bile salts

identify which type of macromolecule is the target of each digestive enzyme or compound: dextrinase

carbohydrate

identify which type of macromolecule is the target of each digestive enzyme or compound: glucoamylase

carbohydrate

identify which type of macromolecule is the target of each digestive enzyme or compound: lactase

carbohydrate

identify which type of macromolecule is the target of each digestive enzyme or compound: pancreatic amylase

carbohydrate

chemical or mechanical digestion: hydrochloric acid

chemical

chemical or mechanical digestion: pancreatic lipase

chemical

chemical or mechanical digestion: pepsin

chemical

chemical or mechanical digestion: salivary amylase

chemical

What is the initial segment of the small intestine?

duodenum

List, in order from top to bottom, the segments of the small intestine.

duodenum jejunum ileum

In order to improve fat digestion, large fat globules must first be dispersed into smaller droplets in a process called

emulsification

In which process are large drops of fats broken apart into smaller fat droplets?

emulsification

The __________ synthesizes bile acids by metabolizing __________.

liver; cholesterol

The physical breakdown of food into smaller particles is known as _______ digestion.

mechanical

A(n) ______ is any enzyme that digests proteins.

protease

identify which type of macromolecule is the target of each digestive enzyme or compound: dipeptidase

protein

identify which type of macromolecule is the target of each digestive enzyme or compound: trypsin

protein

What is a protease?

protein digesting enzyme

5. The build up of pepsin will then digest ____________ .

proteins

The __________ regulates the flow of contents from the stomach to the duodenum.

pyloric sphincter

Which liver function contributes to the process of digestion?

secretion of bile

Muscular contractions called _____ involve alternating ring-like constrictions at several places along the intestine.

segmentation

What is the source of maltase?

small intestinal brush border (microvilli)