Page 103 - Science Class 07

two upper chambers called atria (singular: skin. However, pulmonary and umbilical veins
atrium) and two lower chambers called are the only veins that carry oxygenated blood
ventricles. in the en re body.

Aorta
Pulmonary artery
Pulmonary veins

Le atrium
Right atrium

Le ventrile

Right Ventricle

Heart Veins
Capillaries
Though there are other animals that possess a
heart, however, the way their circulatory Capillaries are very thin tube which act as a
system func ons are quite different from medium between arteries and veins. An
humans. And in some cases, the human exchange of materials between the blood and
circulatory system is more advanced than that the cells of the ssues takes place through
of other animals like insects or molluscs, where these thin walls of the capillaries.
the open circulatory system is observed. ROLE OF LIVER AND KIDNEYS

BLOOD VESSELS The liver receives its blood supply through the

There is a complicated network of thin blood hepa c artery, a small branch of the aorta.
tubes all around our body. These muscular Blood from the intes ne is also brought to the
tubes are called blood vessels. These are there liver where excess of certain nutrients is
types of blood vessels. These blood vessels converted into suitable forms for storage. The
help in circula on of blood. blood vessel that carries the blood from the
intes ne to the liver is called the hepa c vein
Arteries
(a vein that begins and ends in capillaries is
Arteries are blood vessels that transport
called a portal vein). Blood from the liver is
oxygenated blood from the heart to various
carried by the hepa c vein that joins the
parts of the body. They are thick, elas c and
inferior vena cava.
are divided into a small network of blood
Renal arteries arising from the dorsal aorta
vessels called capillaries. The only excep on to
supply the kidneys and renal veins that join the
this is the pulmonary arteries which carries
inferior vena cava carry the blood away from
deoxygenated blood to the lungs.
the kidneys.
Veins

Veins are blood vessels that carry de-
oxygenated blood towards the heart from
various parts of the body. They are thin, elas c
and are present closer to the surface of the
Liver Kidney

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