The composition and functions of blood

Blood is the fluid that transports substances around the human circulatory system.

Blood consists of:

• Plasma - Mostly water, transports substances in solution.
• Red blood cells - Carry oxygen.
• White blood cells - Immune cells.
• Platelets - Involved in clotting.

Functions of blood:

• Transports oxygen and carbon dioxide.
• Transports nutrients from digestion.
• Transports waste for excretion.
• Transports hormones.
• Transports food from storage.
• Transports clotting factors.