14.2 How Do The Parts Of The Human Digestive System Work Together

Question 1

Physical process of digestion

Answer 1

Food broken down into smaller pieces by physical/mechanical means i.e. crushing/grinding/mixing

Question 2

Chemical process of digestion

Answer 2

Food broken down into small molecules through action of (biological molecules) enzymes

Question 3

Function of enzyme

Answer 3

Speed up breakdown of large food molecules into small molecules

Question 4

What are enzymes? (Don’t need to memorize? Just know)

Answer 4

Biological molecules produced by digestive system
Specific (act on only one type of substance)

Question 5

Enzymes and end products of 3 main food groups

Answer 5

Carbohydrates- digested by carbohydrases into simple sugars
Proteins- digested by proteases into amino acids
Fats- digested by lipases into fatty acids & glycerol

Question 6

Where does digestion of carbohydrates, proteins and fats take place?

Answer 6

Carbohydrates: mouth, gullet, small intestine
Proteins: stomach, small intestine
Fats: small intestine

Question 7

What happens in the mouth (physical and chemical digestion if any/other)

Answer 7

Physical: strong teeth and jaw muscles in mouth cut and crush food into smaller pieces
Chemical: saliva in mouth contains carbohydrases -> partial digestion of starch begins in mouth
Other: saliva softens and lubricates food for easier swallowing

Question 8

gullet

Answer 8

Physical: none
Chemical: gullet does not release any digestive juice
but starch from mouth continues to be digested by carbohydrases mixed with food
other: muscles of gullet push food towards stomach

Question 9

stomach

Answer 9

physical: churns food into smaller pieces
chemical: releases gastric juices containing proteases to digest proteins
other:
- releases gastric juice containing hydrochloric acid -> kills harmful microorganisms & provides right conditions for proteases to act
- thick layer of mucus -> protect tissue from damage caused by hydrochloric acid & proteases in gastric juice
- muscles at both ends of stomach control food entering and leaving stomach

Question 10

small intestine

Answer 10

physical: none
chemical:
main site for chemical digestion due to numerous enzymes released
carbohydrates, proteins & fats fully digested here

Question 11

large intestine

Answer 11

some of the remaining water & mineral salts in food absorbed here

Question 12

rectum

Answer 12

indigestible food & waste for faeces, temporarily stored here before leaving body

Question 13

anus

Answer 13

faeces released through this opening