Components and Functions of Blood

The blood is made out of 4 main components:

1. Red Blood Cells

• Red Blood Cells are specialised to carry OXYGEN.
• They have NO NUCLEUS to increase space to carry OXYGEN.
• They have a BICONCAVE DISC shape, increasing SURFACE AREA to carry more oxygen.
• Red blood cells contain HAEMOGLOBIN, a protein that binds to oxygen in the lungs and releases it in body tissues.

2. White Blood Cells

• White Blood Cells fight INFECTION and are a key part of the IMMUNE SYSTEM. 
• They can change shape to ENGULF pathogens by PHAGOCYTOSIS.
• Some white blood cells produce ANTIBODIES and ANTITOXINS to fight infections.

3. Platelets

• Platelets are cell fragments important for BLOOD CLOTTING.
• They activate at injury sites to form clots, preventing excessive bleeding.
• A lack of platelets can lead to EXCESSIVE BLEEDING and INFECTION.

4. Plasma

• Plasma is the LIQUID in blood, which carries all the substances.
• It transports red blood cells, white blood cells, platelets, nutrients, hormones, proteins, carbon dioxide and urea