Body Systems and Health

The Composition of Blood

Starter Questions

1. What is the heart’s job?

2. What is the heart made of?

3. How many chambers are present in the heart?

4. Name 3 substances blood transports in/out of the body?

5. Name the blood vessel which carries blood to the heart.

Starter Possible Answers

1. The heart’s job is to pump blood around the body

2. The heart is made of muscle

3. The heart has 4 chambers

4. Materials the blood transports include: oxygen, food, waste materials and carbon dioxide

5. Veins carry blood to the heart

Starter RIDDLE OPTION

FULL OF HOLES, BUT STILL HOLDS WATER

What is full of holes but still holds water?

A SPONGE

Learning Intention

Develop my knowledge of blood

Success Criteria

• Explain the composition of blood

• Describe what each part of the blood does in the body

• State what volume of blood is present in the human body.

What is blood?

•Blood seems to be a red liquid, but the liquid part is really pale yellow. You can show this by leaving some blood to settle.

•This liquid is called plasma.

•The red colour is due to the red blood cells (RBCs).

•There are also white blood cells (WBCs) and platelets.

Blood

Blood is made up of different parts

1. Red blood cells

2. White blood cells

3. Plasma

4. Platelets

Blood Cells

White blood cells stained purple.

Lots of red blood cells and

one white blood cell.

TASK: Cut, stick and label the diagram

White blood

cell Red Blood Cell

Plasma

Platelet

Functions of blood

TASK: Copy the table and then watch the clips on the next slide to help you complete it

Part of blood Appearance Function

Red blood cells Disc shaped cells

Irregular shaped cells

Small fragments Clotting of blood

Pale yellowy liquid Carries food, waste

and carbon dioxide

What does each part of the blood do?

•Red blood cells are the oxygen carriers.

Animation of red blood cells

•White blood cells are part of the body’s defences and help to fight infection.

White blood cells engulfing bacteria

Platelets help to heal wounds by clotting the blood at the site of an injury.

Action of Platelets at Wound

•Plasma is mainly water and carries dissolved food, waste, carbon dioxide and many other chemicals around the body.

Functions of blood

TASK: Copy the table and then watch the clips on the next slide to help you complete it

Part of blood Appearance Function

Red blood cells Disc shaped cells

Irregular shaped cells

Small fragments Clotting of blood

Pale yellowy liquid Carries food, waste

and carbon dioxide

Carry oxygen

White blood

cells Fight infection

Platelets

Plasma

How much blood?

Look at the jar containing the ‘blood’.

This represents the average volume of blood in the human body.

Estimate how much blood you have in your body and write it down in your notebook.

The average volume of blood in the human body is

5 litres

Plenary Questions

1.What part of the blood fights infection?

2.What part of the blood aids blood to clot?

3.Which part of the blood carries oxygen

around the body?

4.Which part of the blood carries food and

waste materials?

Plenary ANSWERS 1. Which part of the blood fights infection?

White blood cells

2. What part of the blood aids blood to clot?

Platelets

3. Which part of the blood carries oxygen around

the body?

Red blood cells

4. Which part of the blood carries food and waste

materials?

Plasma

Learning Intention - Review

Develop my knowledge of blood

Success Criteria

• Explain the composition of blood

• Describe what each part of the blood does in the body

• State what volume of blood is present in the human body.