Year 7 Biology: Digestion

What is Digestion?

Digestion is the process where our bodies break down the food we eat into smaller parts. This allows our bodies to use the nutrients from food for energy, growth, and repair.

Why is Digestion Important?

Digestion is important because our bodies need nutrients to function properly. Without digestion, we wouldn’t be able to get all the vitamins and minerals from our food.

How Does Digestion Work?

The process of digestion happens in several stages:

1. Mouth

• Chewing: When we eat, our teeth chew the food into smaller pieces. This makes it easier to swallow.
• Saliva: Our saliva (spit) contains enzymes that start breaking down the food.

2. Oesophagus

• After swallowing, food travels down a tube called the oesophagus. This tube connects the mouth to the stomach.
• The food moves down by a process called peristalsis, which is a series of muscle contractions.

3. Stomach

• In the stomach, food mixes with strong acids and enzymes. This helps to break down food even more.
• The stomach has a thick wall to protect itself from these strong acids.

4. Small Intestine

• After the stomach, food moves into the small intestine. Here, most of the digestion and absorption of nutrients occurs.
• The walls of the small intestine are lined with tiny finger-like projections called villi. These villi help absorb nutrients into the blood.

5. Large Intestine

• Any leftover waste moves into the large intestine. Here, water is absorbed, and the remaining waste is prepared for exit from the body as poo.

Tips and Tricks to Remember Digestion:

• Think of digestion like a factory. Food goes in raw and comes out as useful products.
• Remember the order: Mouth → Oesophagus → Stomach → Small Intestine → Large Intestine
• Use a diagram to visualise each part of the digestive system!

Questions About Digestion

Easy Level Questions (20)

1. What is digestion?
2. Where does digestion start?
3. What do our teeth do to food?
4. What part of the digestive system connects the mouth to the stomach?
5. What do we call the tube that carries food to the stomach?
6. What does the stomach mix food with?
7. What is the main job of the small intestine?
8. What are villi?
9. What happens in the large intestine?
10. What do we call the waste that leaves our body?
11. What type of food do we need to digest?
12. Why do we need nutrients?
13. What does saliva do to food?
14. How does food move down the oesophagus?
15. What protects the stomach from its own acids?
16. What happens to water in the large intestine?
17. Does digestion happen all at once or in stages?
18. What role do enzymes play in digestion?
19. Can you name one type of nutrient we get from food?
20. Why is digestion important for our health?

Medium Level Questions (20)

1. Describe the process of chewing and its benefits.
2. What is peristalsis?
3. How do enzymes in saliva help digestion?
4. Why is the stomach considered a muscular organ?
5. Explain how nutrients are absorbed in the small intestine.
6. Why are villi important for digestion?
7. What happens to the food mixture in the stomach?
8. How does the body use the nutrients absorbed?
9. What is the role of the large intestine?
10. Why do we call the remaining waste “faeces”?
11. What is the difference between mechanical and chemical digestion?
12. How is the digestive system like a factory?
13. What can happen if digestion does not work properly?
14. What types of food are easier to digest?
15. Why is it important to chew food well?
16. How does the body know when to start digesting food?
17. What happens to undigested food in the large intestine?
18. Can you name the organs involved in digestion?
19. Why might someone need to change their diet?
20. How does digestion help us grow?

Hard Level Questions (20)

1. Explain the role of hydrochloric acid in the stomach.
2. How do digestive enzymes work?
3. What happens if the small intestine is damaged?
4. Describe how nutrients enter the bloodstream from the small intestine.
5. How does the body create energy from digested food?
6. What disorders can affect the digestive system?
7. Explain the difference between soluble and insoluble fibre.
8. How does the liver assist in the digestion process?
9. What is the role of bile in digestion?
10. Discuss how the digestive system changes as we age.
11. Why is fibre important in our diet?
12. How do different types of food affect digestion?
13. What is lactose intolerance?
14. How can stress impact digestion?
15. What are the long-term effects of poor digestion?
16. Why is it important to drink water during digestion?
17. How does the body signal when we are hungry?
18. What is the function of the pancreas in digestion?
19. How do food allergies impact the digestive process?
20. What advancements have been made in understanding the digestive system?

Answers and Explanations

Easy Level Answers

1. Breaking down food.
2. In the mouth.
3. They chew it into smaller pieces.
4. Oesophagus.
5. Oesophagus.
6. Acids and enzymes.
7. To absorb nutrients.
8. Tiny projections that absorb nutrients.
9. Water is absorbed.
10. Poo.
11. All types of food.
12. For energy and health.
13. It starts breaking down food.
14. By muscle contractions.
15. The stomach wall is thick.
16. Water is absorbed.
17. In stages.
18. They help break down food.
19. Carbohydrates, proteins, fats, etc.
20. To stay healthy.

Medium Level Answers

1. Chewing breaks food into smaller pieces to aid digestion.
2. A muscle contraction that moves food through the digestive system.
3. Saliva enzymes start breaking down carbohydrates.
4. It mixes food with acids to break it down.
5. Nutrients pass through villi into the blood.
6. They increase surface area for absorption.
7. It turns into a thick liquid.
8. The body uses nutrients for energy and growth.
9. To absorb water and form waste.
10. Solid waste that exits the body.
11. Mechanical is physical, chemical is with enzymes.
12. Food goes in, nutrients come out.
13. Problems with digestion can occur.
14. Soft foods are easier to digest.
15. It helps enzymes work better.
16. Signals from the brain.
17. It’s turned into waste.
18. It produces enzymes and insulin.
19. They can cause digestion problems.
20. To help with digestion.

Hard Level Answers

1. It helps break down food and kill bacteria.
2. They break down complex molecules into simpler ones.
3. Nutrients would not be absorbed properly.
4. They pass through the intestinal walls into the bloodstream.
5. The body converts nutrients into energy.
6. Conditions like IBS, Crohn’s disease, etc.
7. Soluble absorbs water; insoluble helps digestion.
8. It produces bile for fat digestion.
9. Bile helps digest fats in the small intestine.
10. The digestive system can slow down.
11. It helps keep the digestive system healthy.
12. Some foods digest faster than others.
13. The body cannot digest lactose.
14. Stress can slow down digestion.
15. Long-term discomfort and health problems.
16. It helps dissolve nutrients.
17. Signals from the stomach and brain.
18. It produces enzymes and regulates blood sugar.
19. They can cause allergic reactions.
20. Research continues to explore digestion.

Feel free to ask questions or for clarification on any of these topics!