Biology Chapter 9: The Digestive System

Question 1

Intracellular digestion

Answer 1

involves the oxidation of glucose and fatty acids to make energy.

Question 2

Extracellular digestion

Answer 2

occurs in the lumen of the alimentary canal

Question 3

Mechanical digestion

Answer 3

physical breakdown of large food particles into smaller food particles

Question 4

Chemical digestion

Answer 4

enzymatic cleavage of chemical bonds, such as the peptide bonds of proteins or the glycosidic bonds of startches.

Question 5

The pathway of the digestive tract

Answer 5

oral cavity - pharynx - esophagus - stomach - small intestine - large intestine - rectum

Question 6

accessory organs of digestion

Answer 6

salivary glands, pancreas, liver and gallbladder

Question 7

Enteric nervous system

Answer 7

In the wall of the alimentary canal and controls peristalsis. Its activity is upregulated by the parasympathetic nervous system and is downregulated by the sympathetic nervous system.

Question 8

Antidiuretic hormone and aldosterone

Answer 8

promote thirst

Question 9

Glucagon and ghrelin

Answer 9

promote hunger

Question 10

Leptin and cholecystokinin

Answer 10

promote satiety

Question 11

What starts the mechanical digestion of food?

Answer 11

mastication

Question 12

What starts the chemical digestion of food?

Answer 12

amylase and lipase in the mouth

Question 13

What is food formed into before swallowing?

Answer 13

a bolus

Question 14

Pharynx

Answer 14

connects the mouth and posterior nasal cavity to the esophagus

Question 15

Esophagus

Answer 15

propels food to the stomach using peristalsis.

Question 16

Food enters the stomach through:

Answer 16

the lower esophageal (cardiac) sphincter

Question 17

What are the 4 parts of the stomach?

Answer 17

fundus, body, antrum, and pylorus

Question 18

Stomach is folded into

Answer 18

rugae - has a lesser and a greater curvature

Question 19

Mucous Cells

Answer 19

produce a bicarbonate-rich mucous to protect the stomach

Question 20

Chief cells

Answer 20

secrete pepsinogen - a protease activated by the acidic environment of the stomach

Question 21

Parietal cells

Answer 21

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

Question 22

G cells

Answer 22

secrete gastrin - a peptide hormone that increases HCl secretion and gastric motility

Question 23

After mechanical and chemical digestion in the stomach, the food particles are called

Answer 23

Chyme

Question 24

Food passes into the duodemum through:

Answer 24

pyloric sphincter

Question 25

Duodenum

Answer 25

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

Question 26

Disaccharidases

Answer 26

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

Question 27

Brush border peptidases

Answer 27

aminopeptidase and dipeptidases

Question 28

Enteropeptidase

Answer 28

activates typsinogen and procarboxypeptidases, initiating an activation cascade

Question 29

Secretin

Answer 29

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

Question 30

Cholecystokinin

Answer 30

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

Question 31

Acinar cells

Answer 31

in pancreas - produce pancreatic juices that contain bicarbonate, pancreatic amylase, pancreatic peptidases (trypsinogen, chymotrypsinogen, carboxypeptidases A and B) and pancreatic lipase

Question 32

Liver synthesizes

Answer 32

bile, which cam be stored in the gallbladder or secreted into the duodenum directly.

Question 33

Bile

Answer 33

emulsifies fats, making them soluble and increasing surface area - main components are bile salts, pigments (bilirubin) and cholesterol.

Question 34

Liver processes

Answer 34

nutrients (through glycogenesis and glycogenolysis, storage of and mobilization of fats and gluconeogenesis) , produces urea, detoxifies chemicals, activates or inactivates medications, produces bile and synthesizes albumin and clotting factors

Question 35

Gallbladder

Answer 35

stores and concentrates bile

Question 36

Jejunum and ileum

Answer 36

Primarily involved in absorption

Question 37

villi

Answer 37

lines the small intestine, lined with microvilli - increase the surface area available for absorption
Contain a capillary bed and a lacteal, a vessel of lymphatic system

Question 38

What enters the villi’s capillary bed?

Answer 38

water-soluble compounds like monosaccharides, amino acids, water-soluble vitamins, small fatty acids and water, enter the capillary bed

Question 39

What enters the lacteal of the villi?

Answer 39

fat-soluble compounds, such as fats, cholesterol, and fat-soluble vitamins

Question 40

Large intestine

Answer 40

absorbs water and salts, forming semisolid feces

Question 41

cecum

Answer 41

outpocketing that accepts fluid from the small intestine through the ileocecal valve and is the site of the appendiz.

Question 42

Colon

Answer 42

divided into ascending, transverse, descending and sigmoid portions

Question 43

Rectum

Answer 43

Stores feces, which are then exreted through the anus

Question 44

Gut bacteria produce

Answer 44

vitamin K and biotin