Topic 8

Question 1

Define ingestion

Answer 1

Intake of food into the body

Question 1

Define Digestion

Answer 1

Breaking down large food molecules into small soluble molecules

Question 2

Why is digestion important / necessary?

Answer 2

1. Food molecules are mostly insoluble in water
2. Food molecules are too large to pass through the gut wall into the bloodstream.

Question 3

Define absorption

Answer 3

taking digested food molecules into body cells

Question 4

Define assimilation

Answer 4

body cells making use of absorbed food molecules

Question 5

Define egestion/defecation

Answer 5

removing undigested matter from the body

Question 6

How do teeth help in physical digestion

Answer 6

teeth grind and cut food to increase surface area to volume ratio so enzymes work more efficiently, plus make food easier to swallow

Question 7

How do salivary glands help in chemical digestion

Answer 7

the presence of food causes a reflex which makes salivary glands secrete saliva

Question 8

What are the contents / function of saliva

Answer 8

Saliva contains mucin which helps to protect the soft lining of the mouth from abrasion and lubricates the food
Antibacterial agents in saliva kill bacteria which enter the mouth
Saliva also contains salivary amylase which helps digest starch to maltose

Question 9

Describe oesophagus

Answer 9

long, narrow, muscular tube that stretches to the stomach

Question 10

what muscles does the oesophagus consist of

Answer 10

circular (inner), longitudinal (outer)

Question 11

What is the function of the oesophagus

Answer 11

conduct food by peristalsis to push food downward

Question 12

What is the function of stomach

Answer 12

Conduct peristalsis by smooth walls mix food with gastric juice into chyme(released to duodenum)
Stomach has walls lined with gastric glands that secrete gastric juice

Question 13

What is the contents of gastric juice

Answer 13

Hydrochloric acid:
Kills most harmful bacteria
Provides optimum pH environment for the enzymes to work
Stops action of salivary amylase

Protease:
Breaks down protein to polypeptide to amino acids

Question 14

What is the function of small intestine?

Answer 14

Intestinal glands secrete intestinal juice(carbohydrates, protease, lipase)
Absorb nutrients

Question 15

What is a special characteristic of the small intestine?

Answer 15

Inner wall lined with many small finger-like projections, villi, which have many capillaries(transport absorbed nutrients), and increase surface area for absorbing nutrients

Question 16

What is the function of the gall bladder

Answer 16

store bile

Question 17

function of pancreas

Answer 17

Secrete pancreatic juices(pancreatic amylase, pancreatic lipase, protease)

Question 18

function of liver

Answer 18

Produce, secrete bile

Question 19

what does bile do

Answer 19

(emulsify fat to speed up digestion)

Question 20

what is the function of large intestine

Answer 20

Absorb water and mineral salts into blood

Question 21

why is the stomach unaffected by the acids it holds

Answer 21

stomach walls are lined with mucus to prevent damage from acid