The Blood How many litres of blood do you have in your body? Blood has four main components Plasma Red blood cells White blood cells Platelets

Plasma (55%) Straw coloured solution containing Water with dissolved salts (90%) Plasma proteins (10%) Nutrients, metabolic wastes, hormones, O2, CO2 Plasma proteins help transport vitamins and fight viral and bacterial infections

Red Blood Cells (41%) Carry oxygen (hemoglobin) Produced in bone marrow (2 million/second) No nuclei Life span of ~100 days Gives them a flat disk shape Increased surface area for O2 molecules Flexibility to squeeze through different sized blood vessels

Sickle Cell Anemia

White Blood Cells (3%) Fight infection, parasites, and bacteria Can move through blood vessel walls Your WBC count increases when you have an infection Pus is WBCs and dead bacteria Produced in the bone marrow Life span of years

Platelets (1%) Help with blood clotting Release clotting factors Scab forms

Blood Type

Blood Vessels Arteries Capillaries Veins

Arteries: Capillaries: Veins: Carry blood away from the heart to the body tissues Smaller diameter High pressure Capillaries: Exchange of nutrients and wastes (diffusion gradient) Tiny tubes with large surface area Veins: Carry blood back to the heart Larger diameter Low pressure Valves allow blood to only flow in one direction