B2: Digestive System Review

Question 1

What is the digestive system?

Answer 1

-Group of organs that work together to ingest and break down food and absorb nutrients

Question 2

Describe physical and chemical breakdown

Answer 2

-Physical involves chewing, churning (stomach) and segmenting (intestines)
-chemical: hydrolysis

Question 3

What is the role of the mouth?

Answer 3

-Chews and mixes food with saliva

Question 4

What is the role of the liver?

Answer 4

-Manufactures bile, a substance that facilitates the digestion of fats

Question 5

What is the role of the gall bladder?

Answer 5

-Stores and concentrates bile which is made from the liver
-releases bile into the small intestine to help digest and absorb fats

Question 6

What is the role of the large intestine?

Answer 6

-Absorbs water and salt, passes remaining undigested material and some water out of the body

Question 7

What is the role of the rectum?

Answer 7

-Stores waste prior to elimination

Question 8

What is the role of esophagus?

Answer 8

-Directs food from the mouth to the stomach

Question 9

What is the role of the stomach?

Answer 9

-Adds acid, enzyme and fluid: churns, mixes and grinds food into a liquid mass

Question 10

What is the role of the pancreas?

Answer 10

Manufactures enzymes to digest macromolecules, secretes bicarbonate to neutralize stomach acid that enters the small intestine

Question 11

What is the role of the small intestine?

Answer 11

-Secrets enzymes that digest macromolecules, absorbs hydrolyzed molecules into bloodstream

Question 12

What is the role of the salivary glands?

Answer 12

-Produces saliva
-contains enzymes that help begin digestion by breaking down carbohydrates

Question 13

What is the role of the anus?

Answer 13

-Holds rectum closed, opens to allow elimination

Question 14

What is pepsin?

Answer 14

-Protien digesting enzyme

Question 15

What is the epiglottis?

Answer 15

-Flap of tissue that covers the trachea
-ensures food won’t enter the trachea

Question 16

What is peristalalsis?

Answer 16

-Wave like contracts which push bolus (ball of food made in the mouth) down the esophagus

Question 17

What is amylase?

Answer 17

-Enzyme that breaks down starch into simple sugars (hydrolysis)
-Produced by salivary gland and the pancreas

Question 18

What does the esophageal sphincter do?

Answer 18

-relaxes to allow food to enter the stomach then contracts prevents the acidic contents of the stomach to come out

Question 19

What is chyme?

Answer 19

-Mixture of partially digested food with gastric (digestive) juices in the stomach
-the mixture is the process of the stomach breaking down food

Question 20

What is in gastric juices?

Answer 20

-Water, mucus, salts and hydrochloride acid
-HCI helps kill pathogens

Question 21

Why does the stomach not digest it’s own proteins?

Answer 21

-First it secrets little gastric juice until food is present
-then some stomach cells secrete mucus which prevents gastric juices from harming the cells of the stomach barrier (slippery barrier)
-pepsin is produced in a form that remains inactive until hydrochloric acid is present (pep-sinogen)

Question 22

What does the pyloric sphincter do?

Answer 22

-Controls the movement of chyme into the small intestine

Question 23

What is absorbed in the stomach?

Answer 23

-Water, salts, anti-inflammatory medicines and alcohol is absorbed in the stomach

Question 24

What is segmentation?

Answer 24

-Breaking down chyme into small bits

Question 25

Describe villi

Answer 25

-Long finger like tubes which increase the SA of the small intestine (apx. 10 fold increase)
-Line the inner wall of the small intestine
-each villus is covered in smaller projections called microvilli, which further increase the SA
-increases the small intestines SA make it more efficient for nutrient absorption

Question 26

What is a lacteal?

Answer 26

-Capillary network that intertwines with lymph vessels
-absorb lipids

Question 27

What are proteases?

Answer 27

-enzymes that break down proteins into smaller peptides or amino acids
-e.g. trypsin, pepsin, etc

Question 28

What are carbohydrases?

Answer 28

-Group of enzymes that break down carbohydrates into smaller sugar molecules
-e.g. amylase

Question 29

What do lipases do?

Answer 29

-Lipid digesting enzymes
-break down fats into smaller molecules
-pancreatic lipase breaks down triglycerides into fatty acids and glycerol
-cholesterol lipase removes a fatty acid from a steroid cholesterol
-a third lipase acts on phospholipids and breaks them down into glycerol and fatty acids