Digestive system

Question 1

What is our body made up of?

[Hint: cells –> Organ systems]

Answer 1

Cells –> Tissues –> Organs –> Organ systems

Question 2

Another term for digestive system

Answer 2

Alimentary canal

Question 3

Describe the process of absorption

Answer 3

• Large insoluble molecules broken down into small soluble ones through the process of digestion
• Small soluble molecules pass through the wall of the small intestine into the blood

Question 4

Examples of large and small soluble molecules

Answer 4

Large:

• Carbs
• Proteins
• Starch

Small:
- glucose

Question 5

What are carbohydrates made up of and what is its simplest units

Answer 5

• Carbon
• Hydrogen
• Oxygen

> Monosaccarides [1 unit] (e.g. glucose)

Question 6

What are proteins made up of and what is its simplest units

Answer 6

• Carbon
• Hydrogen
• Oxygen
• Nitrogen

> Can be digested into amino acids

Question 7

What are fats made up of and what is its simplest units

Answer 7

• Carbon
• Hydrogen
• Oxygen

> Glycerol + fatty acids

Question 8

What are enzymes made up of and what is their function

Answer 8

• Made of proteins

> Produced by digestive system to help speed up the rate of chemical digestion of food molecules into small, soluble subunits

Question 9

Differences between chemical and mechanical digestion

Answer 9

Mechanical:

• Physical breaking up of food into smaller pieces
• No new substances are formed

Chemical:

• Chemically breaking down large molecules into smaller soluble ones by enzymes
• New substances are formed

Question 10

Function of mouth + saliva

Answer 10

1. Ingests food
2. Mechanical digestion of food into smaller pieces through chewing
3. Begins chemical digestion of starch into glucose
4. Saliva moistens/ lubricates food

Question 11

Function of esophagus

Answer 11

Transports food to stomach

Question 12

Function of liver

Answer 12

• Produces bile that is secreted into the small intestine
• Is needed to speed up emulsification of fats

[Note: It’s physical digestion]

Question 13

Function of stomach

Answer 13

1. Mechanical digestion by churning up food
2. Hydrochloric acid lowers pH level and Kills bacteria/ micro-organisms
3. Enzymes chemically digests the proteins

Question 14

Function of Gall bladder and bile (green)

Answer 14

• Stores bile

> Bile ONLY speeds up digestion :)

Question 15

Function of pancreas

Answer 15

1. Secretes pancreatic juice, which contains (all) enzymes into the small intestine
   - To neutralise the acidic chyme from the stomach as it is an alkali
   - These enzymes speed up chemical digestion of carbohydrates proteins and fats into small, soluble subunits

Question 16

Describe the process of emulsification

Answer 16

• Large fat droplets are emulsifies to small fat droplets

- This increases the surface area of fat molecules for enzymes to act on

Question 17

Function of the small intestine

Answer 17

1. Large, insoluble nutrients broken down
2. small, water-soluble molecules
3. Absorbed through the wall of the small intestine into the blood stream

Question 18

What is assimilation

Answer 18

The movement of digested food from blood to other body cells

Question 19

How is the small intestine adapted for its function

Answer 19

1. Inner walls of small intestine is highly folded and had finger-lie projections called villi
2. Villi increase surface area, thus increasing the rate of diffusion to volume ratio and hence the rate of absorption of nutrients
3. Rich network of capillaries which absorbs the nutrients quickly, maintaining a steep concentration gradient for rapid diffusion

Question 20

Function of the large intestine

Answer 20

• Undigested food (e.g. Remaining water, vitamins and minerals) are absorbed

Question 21

Effect of reduced absorption of large intestine

Answer 21

Water:

• Dehydration
• Watery stools

Vitamins:

• Less vitamin C –> suffer rom scurvy
• Less vitamin D –> less calcium absorbed, rickets

Minerals
- Less iron absorbed –> less red blood cells made

Question 22

2 possible effects of small intestine have a decreased surface area

Answer 22

1. Less assimilation/ diffusion

2. Slower rate/ less absorption of digested food