Blood Cells
Applied Science: BTEC Level 3 National Extended Diploma, topic 1.4.2
Red Blood Cells
Red blood cells transport oxygen from the lungs to all body cells. They are adapted to do this function because of their features:
Biconcave shape
- Red blood cells have dents on each side.
- We call this a biconcave shape.
- This biconcave shape creates a large surface area and allows for the rapid diffusion of oxygen.
Haemoglobin
- Red blood cells contain haemoglobin, which binds with oxygen in the lungs.
- Haemoglobin carries oxygen which will then be released to the body cells to be used for respiration.
No nucleus
- Red blood cells do not have a nucleus. This frees up more room for haemoglobin.
- This maximises the amount of oxygen that they can carry.
Small size
- Red blood cells are small so that they can pass through tiny capillaries.
White Bloods Cells
White blood cells defend against infections. White blood cells:
Have a nucleus
- Unlike red blood cells, white blood cells have a nucleus.
Can change shape
- White blood cells can change shape.
- This allows them to squeeze through the walls of blood vessels into body tissues and to engulf harmful microorganisms.
Test yourself on Blood Cells
How is a red blood cell adapted to its function?
What would happen if red blood cells had a nucleus?
What is the role of white blood cells?
Why do white blood cells change shape?