NCERT Book Class 7 Science Chapter 7 Transportation in Animals and Plants

7 Transportation in
Animals and Plants

Y
ou have learnt earlier that all
organisms need food, water and
oxygen for survival. They need to
transport all these to various parts of
their body. Further, animals need to
transport wastes to parts from where
they can be removed. Have you
wondered how all this is achieved? Look
Heart
at Fig. 7.1. Do you see the heart and
the blood vessels? They function to Vein
transport substances and together form
the circulatory system. In this chapter,
you shall learn about transport of
Artery
substances in animals and plants.
7.1 CIRCULATORY SYSTEM
Blood
What happens when you get a cut on
your body? Blood flows out. But what
is blood? Blood is the fluid which
flows in blood vessels. It transports
substances like digested food from the
small intestine to the other parts of the
body. It carries oxygen from the lungs
to the cells of the body. It also transports
waste for removal from the body.
How does the blood carry various
substances? Blood is composed of a
fluid, called plasma in which different
types of cells are suspended.

Why is the colour of Fig. 7.1 Circulatory system
blood red ? (Arteries are shown in red colour and veins in blue)