Topic 2.2

Red blood cells (Erythrocytes), White Blood cells (Leucocytes), Platelets and Plasma Also transports protein, nutrients and waste products

Red Blood cells transport oxygen. Absorb oxygen from the lungs and transport it to blood vessels. Adaptations include No nucleus, Contain Haemoglobin, Bioncave shape for large surface area

Defend the body against diseases. Phagocytes engulf bacteria and destroys them.

When skin is broken a scab must be formed to prevent entry of pathogens and prevent blood loss An insoluble mesh if formed of fibrin acroos the wound and they stick together to form a mesh which forms a scab

Carries the blood cells and platelets around the body

Cardiac output= Heart rate x heart rate Stroke volume expands as heart rate increases

The force exerted by blood on arteries walls during ventricular contraction

The force exerted by blood on arteries wall during ventricular relaxation

The heart operates a double circulatory system in which blood flows through twice Pulmonary Circulation- Blood flow between heart and lungs Systemic Circulation- Movement of blood from heart to rest of body and back to heart

Arteries take blood away from the heart to the organs and other body tissues. Arteries have a narrow lumen and thick muscular walls. This allows them to carry blood that is at a high pressure.

Veins carry blood under low pressure from the capillaries and return the blood to the heart. The vein walls have thinner muscular walls than arteries and have a wider lumen. Veins contain valves to prevent the backflow of low-pressure blood.

Capillaries are tiny, thin walled vessels that form a network to take blood through the organs and other body tissues. The dense networks of capillaries present a large surface area, which allows materials to be exchanged between body cells and the blood rapidly. Oxygen and dissolved foods diffuse into body cells from the blood, and carbon dioxide and other waste products diffuse out of body cells into the blood.