Chapter 9: The Digestive System

Question 1

There are two types of digestions:

Answer 1

Intracellular Digestion and Extracellular Digestion.

Question 2

Intracellular Digestion:

Answer 2

Intracellular digestion: is a part of metabolism and involves the oxidation of glucose and fatty acids to make energy.

Question 3

Extracellular Digestion:

Answer 3

Extracellular digestion: “outside of the body”. Here nutrients are obtained from food occurs in the lumen of the alimentary canal.

Question 4

Alimentary Canal:

Answer 4

Alimentary Canal: is the outside of the body. It runs from the mouth to the anus and is sectioned off by sphincters around the canal that can contract to allow compartmentalization of function.

Question 5

Sphincters:

Answer 5

Sphincters: are circular smooth muscles around the canal that can contract to allow compartilization of function. It opens and closes the alimentary canal.

Question 6

Digestion:

Answer 6

Digestion: involves the breakdown of food into its constituent organic molecules. ○ Example: starches and other carbohydrates into monosaccharides, lipids (fats) into free fatty acids and glycerol, and proteins into amino acids. ○ It can be divided into two types: (Mechanical and Chemical)

Question 7

Mechanical Digestion:

Answer 7

This is the physical breakdown of large food particles into smaller food particles.

Question 8

Chemical Digestion:

Answer 8

This is the enzymatic cleavage of chemical bonds, such as the peptide bonds of proteins or the glycosidic bonds of starches.

Question 9

Absorption:

Answer 9

This involves the transport of products of digestion from the digestive tract into the circulatory system for distribution to the body’s tissue and cells.

Question 10

The pathway of the digestive tract is:

Answer 10

oral cavity → pharynx → esophagus → stomach → small intestine → large intestine → rectum.

Question 11

The accessory organs of digestion:

Answer 11

The accessory organs of digestion are the salivary glands, pancreas, liver, and gallbladder. These help and provide enzymes and lubrication necessary to aid the digestion of food.

Question 12

The enteric nervous system:

Answer 12

This is the collections of million neurons that govern the function of gastrolienal system. • Its in the walls of the alimentary canal and controls peristalsis.

Question 13

What do these hormones regulate (feeding behavior): antidiuretic hormone (ADH or vasopressin) and aldosterone.

Answer 13

Antidiuretic hormone (ADH or vasopressin) and aldosterone, promotes thirst;

Question 14

What do these hormones regulate (feeding behavior): glucagon and ghrelin

Answer 14

Glucagon and ghrelin, promote hunger;

Question 15

What do these hormones regulate (feeding behavior): Leptin and cholecystokinin,

Answer 15

Leptin and cholecystokinin, which promote satiety.

Question 16

What starts the mechanical digestion of food and where.

Answer 16

In the oral cavity, mastication starts the mechanical digestion of food,

Question 17

What starts chemical digestion of food and where.

Answer 17

In the salivary amylase, the lipase start the chemical digestion of food. Food is formed into a bolus and swallowed.

Question 18

The Pharynx:

Answer 18

This connects the mouth and posterior nasal cavity to the esophagus.

Question 19

The Esophagus:

Answer 19

This propels food to the stomach using peristalsis. Food enters the stomach through the lower esophageal (cardiac) sphincter.

Question 20

Four Parts of the stomach.

Answer 20

It four parts: fundus, body, antrum, and pylorus. The stomach has a lesser and greater curvature and is thrown into folds called rugae. Numerous secretory cells line the stomach.

Question 21

Mucous cells:

Answer 21

These cells produce bicarbonate-rich mucus to protect the stomach.

Question 22

Chief Cells:

Answer 22

These cells secrete pepsinogen, a protease activated by the acidic environment of the stomach.

Question 23

Parietal Cells:

Answer 23

These cells secrete hydrochloric acid and intrinsic factor, which is needed for vitamin B12 absorption.

Question 24

G Cells:

Answer 24

These cells secrete gastrin, a peptide hormone that increases HCl secretion and gastric motility.

Question 25

Chyme:

Answer 25

This is the food particles in the stomach after mechanical and chemical digestion.

Question 26

How does food pass through the duodenum?

Answer 26

Food passes into the duodenum through the pyloric sphincter.

Question 27

The duodenum:

Answer 27

This is the first part of the small intestine and is primarily involved in chemical digestion.

Question 28

Disaccharidases:

Answer 28

These are brush-border enzymes that break down maltose, isomaltose, lactose, and sucrose into monosaccharides.

Question 29

Enteropeptidas

Answer 29

This activates trypsinogen and procarboxypeptidases, initiating an activation cascade.

Question 30

Secretin:

Answer 30

This stimulates the release of pancreatic juices into the digestive tract and slows motility.

Question 31

Cholecystokinin:

Answer 31

This stimulates bile release from the gallbladder, release of pancreatic juices, and satiety.

Question 32

Peristalsis:

Answer 32

This is the enteric nervous system. This is the rhythmic contractions off the gut tube, in order to move materials through the system. § Its activity is unregulated by the parasympathetic nervous system because it increases secretion, and promotes peristalsis. § Its activity is downregulated by the sympathetic nervous system.