Biology Blood and circulation

• What the blood transports (All)

Oxygen - lungs to body cells

Carbon dioxide - body cells to lungs

Nutrients - gut to body cells

Urea - liver to kidney

Hormones and Antibodies

Blood plasma distributes heat to the body

Why single celled organisms don’t need circulation.

Substances move by diffusion

Oxygen enters directly to the cell membrane

Heart and blood vessels not needed

Very small size

• Examples of Organisms without circulation (3)

Amoeba

Euglena

Paramecium

Single circulation (fish)

Heart-gills-body-heart

Blood pressure is lost at gills

Blood reaches organs slowly

Less efficient

Double circulation

Blood passes though the heart twice per cycle

More efficient than single circulation

Blood reaches the organs faster

Blood pressure is maintained

Right atrium

Receives deoxygenated blood from the body through vena cava

Right ventricle

Pumps deoxygenated blood to lungs through pulmonary vein.

Left atrium

Receives oxygenated blood from the lungs through pulmonary vein

Left ventricle

Pumps oxygenated blood to the whole body through aorta