Blood and Blood Vessels
The contents of blood including red blood cells, white blood cells, platelets and plasma
The following are found inside the blood:
Red blood cells
- These contain haemoglobin which transport the oxygen to cells around the body.
- They have a large surface area so they can transport more oxygen.
- They also have a dent in them which makes them more flexible to fit through small blood vessels.
White blood cells
- These cells fight infection.
- They make antibodies to surround and overcome bacteria.
- Some white blood cells change shape to engulf bacteria.
- This is the yellow part of the blood.
- It contains many substances dissolved in it such as the products of digestion.
- Thick and muscular with only a small hole through the middle so that it can withstand high pressure.
- The arteries carry blood with high levels of oxygen from the heart around the body.
- Thinner wall than the artery and it has lower pressure but a larger space inside.
- The veins also contain valves to prevent the blood from flowing the wrong way
- Very thin wall which is only one cell thick.
- They pass close to cells and allow the blood to leak in and out of them.