Digestive System

Question 1

Name the accessory organs of the digestive system

Answer 1

liver, gallbladder, pancreas, salivary glands

Question 2

Define digestion (general)

Answer 2

the breakdown of large, complex organic molecules into smaller components that can be used by the body

Question 3

What are the four components of digestion?

Answer 3

ingestion, digestion, absorption, egestion

Question 4

Define ingestion

Answer 4

the consumption or taking in of nutrients

Question 5

Define digestion (component of digestion)

Answer 5

the chemical breakdown of large organic molecules into smaller components by enzymes

Question 6

Define absorption

Answer 6

the transport or delivery of digested nutrients to body tissues

Question 7

Define egestion

Answer 7

the elimination of food waste materials from the body

Question 8

What is the human digestive tract also known as and how long is it?

Answer 8

alimentary canal; approximately 6.5 - 9 meters long

Question 9

What enzyme does saliva contain and what does it do?

Answer 9

amylase; breaks down starches into simpler carbohydrates

Question 10

What is a bolus?

Answer 10

A ball of food that is formed with the help of salvia

Question 11

Define peristalsis

Answer 11

wavelike movement that propels the food down the esophagus and through the entire gastrointestinal tract

Question 12

What does the stomach do?

Answer 12

temporary food storage site, food spends ~4hrs in stomach; initial site of protein digestion

Question 13

What are the two sphincters of the stomach?

Answer 13

esophageal/cardiac sphincter and pyloric sphincter

Question 14

What is chyme?

Answer 14

partially digested food

Question 15

What is the role of mucus in the stomach?

Answer 15

Protects stomach from HCI and pespinogen

Question 16

What is pepsin?

Answer 16

a protein digesting enzyme that breaks large protein chains into smaller chains

Question 17

Why is the stomach’s pH so acidic? (between 2.0-3.0)

Answer 17

the high acidity allows pepsin to work and makes the HCl effective at killing pathogens

Question 18

What is a stomach ulcer?

Answer 18

a lesion in the lining of the stomach that occurs when the protective mucus lining breaks down and the cell membranes are exposed to the HCl and pepsin

Question 19

What are the three sections of the small intestine?

Answer 19

duodenum, jejunum, and ileum

Question 20

What does the presence of chyme in the small intestine trigger?

Answer 20

the conversion of prosecretin into secretin

Question 21

What does secretin do?

Answer 21

stimulates the pancreas to release a solution containing bicarbonate ion into the small intestine where it neutralizes the chyme; pH 2.5 –> 9.0 which inactivates the pepsin

Question 22

What is the pancreas?

Answer 22

an accessory digestive organ that produces digestive enzymes and pancreatic juice

Question 23

What is trypsinogen and what does it do?

Answer 23

a protein digesting enzyme released by the pancreas into the small intestine; converts to trypsin and breaks down large protein chains into smaller ones

Question 24

What is the final step of protein digestion?

Answer 24

when erepsins are released from the pancreas and they break smaller protein chains into individual amino acids

Question 25

What is amylase (pancreatic)?

Answer 25

an enzyme that breaks large carbohydrate chains into small chains called disaccharides

Question 26

How do disaccharides get broken down?

Answer 26

small intestine releases disaccharide enzymes that breaks them down into individual sugars

Question 27

What are lipases?

Answer 27

enzymes that break down fats into fatty acids and glycerol; includes pancreatic lipase and phospholipase

Question 28

What is the liver?

Answer 28

a large accessory organ of the digestive system that produces bile and detoxifies substances in the body (i.e. alcohol)

Question 29

What stores bile?

Answer 29

gallbladder

Question 30

What does the presence of lipids in the small intestine trigger?

Answer 30

the release of the hormone cholecystokinin (CCK)

Question 31

What does cholecystokinin do?

Answer 31

triggers the release of bile from the gallbladder

Question 32

What does bile do?

Answer 32

contains bile salts that emulsifies fats

Question 33

How are gallstones formed?

Answer 33

bile contains cholesterol which acts as a binding agent and can cause bile salts to crystalize into gallstones

Question 34

What is jaundice and what causes it?

Answer 34

a yellow discoloration of the skin and tissues cause by a collection of bile pigments in the blood

Question 35

What does the large intestine do?

Answer 35

stores waste products long enough so that water can be reabsorbed from waste; along w/ water, some inorganic salts, minerals, and vitamins are absorbed

Question 36

What is the large intestine home to?

Answer 36

several different types of bacteria that use waste materials to synthesize vitamins B and K

Question 37

What is cellulose and what does it do?

Answer 37

a long chain carbohydrate found in the call wall of plant cells that humans cannot digest; aka fiber; helps bowel movements

Question 38

Where are most nutrients absorbed?

Answer 38

small intestine

Question 39

How are the second and third sections of the small intestine specialized to absorb nutrients?

Answer 39

villi and microvilli to increase surface area; smaller diameter for slower movement and more time spent absorbing nutrients