Page 121 - Biology Form Two

Biology for Secondary Schools

Pulmonary artery
Lungs Pulmonary vein

Aorta
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Vena cava
Heart

Head and arms
Hepatic vein Hepatic artery

Stomach
Liver and intestine
Hepatic portal vein
Mesenteric artery

Kidneys
Renal vein Renal artery

Legs and abdomen
Blood vessels carrying oxygenated blood
Blood vessels carrying deoxygenated blood

Figure 5.13: Blood circulation in the whole human body

Human beings exhibit double circulation, lungs, where gas exchange occurs. In
whereby blood passes through the heart the lungs, blood is oxygenated. It then
twice for each complete circulation. flows back to the heart through the
Double circulation includes pulmonary pulmonary vein, as shown in Figure
circulation and systemic circulation, 5.14. The movement of blood between
as shown in Figure 5.14. In other less the heart and the lungs is called the
complex organisms like fish, blood pulmonary cycle.
goes through the heart only once. This
is known as single circulation. Systemic circulation
Systemic circulation provides different
Pulmonary circulation parts of the body with oxygen and other
Pulmonary circulation transports blood vital substances. In systemic circulation,
between the heart and the lungs. It the pulmonary vein transports blood to
transports deoxygenated blood to the the left auricle, as shown in Figure 5.14.

Student’s Book - Form Two 115

05/10/2024 15:36:40
BIOLOGY FORM 2 NEW.indd 115
BIOLOGY FORM 2 NEW.indd 115 05/10/2024 15:36:40