NCERT Textbook: Transportation in Animals & Plants | Science Class 7 PDF Download

 Page 1


Transportation in
Animals and Plants
7
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
at Fig. 7.1. Do you see the heart and
the blood vessels? They function to
transport substances and together form
the circulatory system. In this chapter,
you shall learn about transport of
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.
Heart
Vein
Artery
Why is the colour of
blood red?
Fig. 7.1  Circulatory system
(Arteries are shown in red colour and veins in blue)
Reprint 2024-25
Page 2


Transportation in
Animals and Plants
7
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
at Fig. 7.1. Do you see the heart and
the blood vessels? They function to
transport substances and together form
the circulatory system. In this chapter,
you shall learn about transport of
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.
Heart
Vein
Artery
Why is the colour of
blood red?
Fig. 7.1  Circulatory system
(Arteries are shown in red colour and veins in blue)
Reprint 2024-25
TRANSPORTATION IN ANIMALS AND PLANTS 71
One type of cells are the red blood
cells (RBC) which contain a red pigment
called haemoglobin. Haemoglobin
binds with oxygen and transports it to
all the parts of the body and ultimately
to all the cells. It will be difficult to
provide oxygen efficiently to all the cells
of the body without haemoglobin. The
presence of haemoglobin makes blood
appear red.
The blood also has white blood cells
(WBC) which fight against germs that
may enter our body.
Boojho fell down while playing a
game and his knee got injured. Blood
was coming out from the cut. After some
time, he noticed that bleeding had
stopped and a dark red clot had plugged
the cut. Boojho was puzzled about this.
The clot is formed because of the
presence of another type of cells in the
blood, called platelets.
Blood vessels
There are different types of blood vessels
in the body. You know that during
inhalation a fresh supply of oxygen fills
the lungs. Oxygen has to be transported
to the rest of the body.
Also, the blood picks up the waste
materials including carbon dioxide from
the cells. This blood has to go back to
the heart for transport to the lungs for
removal of carbon dioxide as you have
learnt in Chapter 6. So, two types of
blood vessels,  arteries and veins are
present in the body. (Fig. 7.1)
Arteries carry oxygen-rich blood
from the heart to all parts of the body.
Since the blood flow is rapid and at a
high pressure, the arteries have thick
elastic walls.
Let us perform an activity to study
the flow of blood through arteries.
Activity 7.1
Place the middle and index finger of
your right hand on the inner side of your
left wrist (Fig. 7.2). Can you feel some
throbbing movements? Why do you
think there is throbbing? This
throbbing is called the pulse and it is
due to the blood flowing in the arteries.
Count the number of pulse beats in one
minute.
How many pulse beats could you
count? The number of beats per minute
is called the pulse rate. A resting
person, usually has a pulse rate between
72 and 80 beats per minute. Find other
places in your body where you can feel
the pulse.
Record your own pulse beats per
minute and those of your classmates.
Insert the values you obtained in
Table 7.1 and compare them.
Fig. 7.2  Pulse in the wrist
Reprint 2024-25
Page 3


Transportation in
Animals and Plants
7
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
at Fig. 7.1. Do you see the heart and
the blood vessels? They function to
transport substances and together form
the circulatory system. In this chapter,
you shall learn about transport of
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.
Heart
Vein
Artery
Why is the colour of
blood red?
Fig. 7.1  Circulatory system
(Arteries are shown in red colour and veins in blue)
Reprint 2024-25
TRANSPORTATION IN ANIMALS AND PLANTS 71
One type of cells are the red blood
cells (RBC) which contain a red pigment
called haemoglobin. Haemoglobin
binds with oxygen and transports it to
all the parts of the body and ultimately
to all the cells. It will be difficult to
provide oxygen efficiently to all the cells
of the body without haemoglobin. The
presence of haemoglobin makes blood
appear red.
The blood also has white blood cells
(WBC) which fight against germs that
may enter our body.
Boojho fell down while playing a
game and his knee got injured. Blood
was coming out from the cut. After some
time, he noticed that bleeding had
stopped and a dark red clot had plugged
the cut. Boojho was puzzled about this.
The clot is formed because of the
presence of another type of cells in the
blood, called platelets.
Blood vessels
There are different types of blood vessels
in the body. You know that during
inhalation a fresh supply of oxygen fills
the lungs. Oxygen has to be transported
to the rest of the body.
Also, the blood picks up the waste
materials including carbon dioxide from
the cells. This blood has to go back to
the heart for transport to the lungs for
removal of carbon dioxide as you have
learnt in Chapter 6. So, two types of
blood vessels,  arteries and veins are
present in the body. (Fig. 7.1)
Arteries carry oxygen-rich blood
from the heart to all parts of the body.
Since the blood flow is rapid and at a
high pressure, the arteries have thick
elastic walls.
Let us perform an activity to study
the flow of blood through arteries.
Activity 7.1
Place the middle and index finger of
your right hand on the inner side of your
left wrist (Fig. 7.2). Can you feel some
throbbing movements? Why do you
think there is throbbing? This
throbbing is called the pulse and it is
due to the blood flowing in the arteries.
Count the number of pulse beats in one
minute.
How many pulse beats could you
count? The number of beats per minute
is called the pulse rate. A resting
person, usually has a pulse rate between
72 and 80 beats per minute. Find other
places in your body where you can feel
the pulse.
Record your own pulse beats per
minute and those of your classmates.
Insert the values you obtained in
Table 7.1 and compare them.
Fig. 7.2  Pulse in the wrist
Reprint 2024-25
SCIENCE 72
Table 7.1 Pulse rate
S. No. Name Pulse per minute
1.
2.
3.
4.
5.
Paheli explained that the
pulmonary artery carries blood
from the heart, so it is called an
artery and not a vein. It carries
carbon dioxide-rich blood to the
lungs. Pulmonary vein carries
oxygen-rich blood from the
lungs to the heart. 
Veins are the vessels which carry
carbon dioxide-rich blood from all parts
of the body back to the heart. The veins
have thin walls. There are valves present
in veins which allow blood to flow only
towards the heart.
Refer to Fig. 7.3. Do you see the
arteries divide into smaller vessels? On
reaching the tissues, they divide further
into extremely thin tubes called
capillaries. The capillaries join to form
veins which empty into the heart.
Heart
The heart is an organ which beats
continuously to act as a pump for the
transport of blood, which carries other
substances with it.
Imagine a pump working for
years without stopping! Absolutely
impossible. Yet our heart works like a
pump non-stop. Let us now learn about
the heart.
The heart is located in the chest
cavity with its lower tip slightly tilted
towards the left (Fig. 7.1). Hold your
fingers inwards on your palm. That
Capillaries
Vein
Artery
Heart
Lungs
I am confused! I have learnt
that an artery always
carries oxygen-rich blood. 
Pulmonary
artery
Pulmonary
vein
Fig. 7.3  Schematic diagram of circulation
Blood Donation
Hundreds of people die due to
unavailability of blood. Voluntary
blood donation is harmless and
painless and can save precious lives.
Blood can be donated at hospitals and
other places authorised by the
government. Donated blood are stored
with special care in Blood Banks.
Reprint 2024-25
Page 4


Transportation in
Animals and Plants
7
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
at Fig. 7.1. Do you see the heart and
the blood vessels? They function to
transport substances and together form
the circulatory system. In this chapter,
you shall learn about transport of
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.
Heart
Vein
Artery
Why is the colour of
blood red?
Fig. 7.1  Circulatory system
(Arteries are shown in red colour and veins in blue)
Reprint 2024-25
TRANSPORTATION IN ANIMALS AND PLANTS 71
One type of cells are the red blood
cells (RBC) which contain a red pigment
called haemoglobin. Haemoglobin
binds with oxygen and transports it to
all the parts of the body and ultimately
to all the cells. It will be difficult to
provide oxygen efficiently to all the cells
of the body without haemoglobin. The
presence of haemoglobin makes blood
appear red.
The blood also has white blood cells
(WBC) which fight against germs that
may enter our body.
Boojho fell down while playing a
game and his knee got injured. Blood
was coming out from the cut. After some
time, he noticed that bleeding had
stopped and a dark red clot had plugged
the cut. Boojho was puzzled about this.
The clot is formed because of the
presence of another type of cells in the
blood, called platelets.
Blood vessels
There are different types of blood vessels
in the body. You know that during
inhalation a fresh supply of oxygen fills
the lungs. Oxygen has to be transported
to the rest of the body.
Also, the blood picks up the waste
materials including carbon dioxide from
the cells. This blood has to go back to
the heart for transport to the lungs for
removal of carbon dioxide as you have
learnt in Chapter 6. So, two types of
blood vessels,  arteries and veins are
present in the body. (Fig. 7.1)
Arteries carry oxygen-rich blood
from the heart to all parts of the body.
Since the blood flow is rapid and at a
high pressure, the arteries have thick
elastic walls.
Let us perform an activity to study
the flow of blood through arteries.
Activity 7.1
Place the middle and index finger of
your right hand on the inner side of your
left wrist (Fig. 7.2). Can you feel some
throbbing movements? Why do you
think there is throbbing? This
throbbing is called the pulse and it is
due to the blood flowing in the arteries.
Count the number of pulse beats in one
minute.
How many pulse beats could you
count? The number of beats per minute
is called the pulse rate. A resting
person, usually has a pulse rate between
72 and 80 beats per minute. Find other
places in your body where you can feel
the pulse.
Record your own pulse beats per
minute and those of your classmates.
Insert the values you obtained in
Table 7.1 and compare them.
Fig. 7.2  Pulse in the wrist
Reprint 2024-25
SCIENCE 72
Table 7.1 Pulse rate
S. No. Name Pulse per minute
1.
2.
3.
4.
5.
Paheli explained that the
pulmonary artery carries blood
from the heart, so it is called an
artery and not a vein. It carries
carbon dioxide-rich blood to the
lungs. Pulmonary vein carries
oxygen-rich blood from the
lungs to the heart. 
Veins are the vessels which carry
carbon dioxide-rich blood from all parts
of the body back to the heart. The veins
have thin walls. There are valves present
in veins which allow blood to flow only
towards the heart.
Refer to Fig. 7.3. Do you see the
arteries divide into smaller vessels? On
reaching the tissues, they divide further
into extremely thin tubes called
capillaries. The capillaries join to form
veins which empty into the heart.
Heart
The heart is an organ which beats
continuously to act as a pump for the
transport of blood, which carries other
substances with it.
Imagine a pump working for
years without stopping! Absolutely
impossible. Yet our heart works like a
pump non-stop. Let us now learn about
the heart.
The heart is located in the chest
cavity with its lower tip slightly tilted
towards the left (Fig. 7.1). Hold your
fingers inwards on your palm. That
Capillaries
Vein
Artery
Heart
Lungs
I am confused! I have learnt
that an artery always
carries oxygen-rich blood. 
Pulmonary
artery
Pulmonary
vein
Fig. 7.3  Schematic diagram of circulation
Blood Donation
Hundreds of people die due to
unavailability of blood. Voluntary
blood donation is harmless and
painless and can save precious lives.
Blood can be donated at hospitals and
other places authorised by the
government. Donated blood are stored
with special care in Blood Banks.
Reprint 2024-25
TRANSPORTATION IN ANIMALS AND PLANTS 73
makes your fist. Your heart is roughly
the size of your fist.
What will happen if the blood rich in
oxygen and the blood rich in carbon
dioxide mix with each other? To avoid
this from happening, the heart has four
chambers. The two upper chambers are
called the atria (singular: atrium) and
the two lower chambers are called the
ventricles (Fig. 7.4). The partition
between the chambers  helps to avoid
Paheli wonders which side of
the heart will have oxygen-rich
blood and which side will have
carbon dioxide-rich blood.
Fig. 7.4  Sections of human heart
Vena Cava
Right atrium
Right ventricle
Partition completely
separating the two
halves
Left atrium
Left ventricle
Pulmonary artery
Pulmonary vein
mixing up of blood rich in oxygen with
the blood rich in carbon dioxide.
To understand the functioning of the
circulatory system, start from the right
side of the heart in Fig. 7.3 and follow
the arrows. These arrows show the
direction of the blood flow from the heart
Aorta
Reprint 2024-25
Page 5


Transportation in
Animals and Plants
7
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
at Fig. 7.1. Do you see the heart and
the blood vessels? They function to
transport substances and together form
the circulatory system. In this chapter,
you shall learn about transport of
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.
Heart
Vein
Artery
Why is the colour of
blood red?
Fig. 7.1  Circulatory system
(Arteries are shown in red colour and veins in blue)
Reprint 2024-25
TRANSPORTATION IN ANIMALS AND PLANTS 71
One type of cells are the red blood
cells (RBC) which contain a red pigment
called haemoglobin. Haemoglobin
binds with oxygen and transports it to
all the parts of the body and ultimately
to all the cells. It will be difficult to
provide oxygen efficiently to all the cells
of the body without haemoglobin. The
presence of haemoglobin makes blood
appear red.
The blood also has white blood cells
(WBC) which fight against germs that
may enter our body.
Boojho fell down while playing a
game and his knee got injured. Blood
was coming out from the cut. After some
time, he noticed that bleeding had
stopped and a dark red clot had plugged
the cut. Boojho was puzzled about this.
The clot is formed because of the
presence of another type of cells in the
blood, called platelets.
Blood vessels
There are different types of blood vessels
in the body. You know that during
inhalation a fresh supply of oxygen fills
the lungs. Oxygen has to be transported
to the rest of the body.
Also, the blood picks up the waste
materials including carbon dioxide from
the cells. This blood has to go back to
the heart for transport to the lungs for
removal of carbon dioxide as you have
learnt in Chapter 6. So, two types of
blood vessels,  arteries and veins are
present in the body. (Fig. 7.1)
Arteries carry oxygen-rich blood
from the heart to all parts of the body.
Since the blood flow is rapid and at a
high pressure, the arteries have thick
elastic walls.
Let us perform an activity to study
the flow of blood through arteries.
Activity 7.1
Place the middle and index finger of
your right hand on the inner side of your
left wrist (Fig. 7.2). Can you feel some
throbbing movements? Why do you
think there is throbbing? This
throbbing is called the pulse and it is
due to the blood flowing in the arteries.
Count the number of pulse beats in one
minute.
How many pulse beats could you
count? The number of beats per minute
is called the pulse rate. A resting
person, usually has a pulse rate between
72 and 80 beats per minute. Find other
places in your body where you can feel
the pulse.
Record your own pulse beats per
minute and those of your classmates.
Insert the values you obtained in
Table 7.1 and compare them.
Fig. 7.2  Pulse in the wrist
Reprint 2024-25
SCIENCE 72
Table 7.1 Pulse rate
S. No. Name Pulse per minute
1.
2.
3.
4.
5.
Paheli explained that the
pulmonary artery carries blood
from the heart, so it is called an
artery and not a vein. It carries
carbon dioxide-rich blood to the
lungs. Pulmonary vein carries
oxygen-rich blood from the
lungs to the heart. 
Veins are the vessels which carry
carbon dioxide-rich blood from all parts
of the body back to the heart. The veins
have thin walls. There are valves present
in veins which allow blood to flow only
towards the heart.
Refer to Fig. 7.3. Do you see the
arteries divide into smaller vessels? On
reaching the tissues, they divide further
into extremely thin tubes called
capillaries. The capillaries join to form
veins which empty into the heart.
Heart
The heart is an organ which beats
continuously to act as a pump for the
transport of blood, which carries other
substances with it.
Imagine a pump working for
years without stopping! Absolutely
impossible. Yet our heart works like a
pump non-stop. Let us now learn about
the heart.
The heart is located in the chest
cavity with its lower tip slightly tilted
towards the left (Fig. 7.1). Hold your
fingers inwards on your palm. That
Capillaries
Vein
Artery
Heart
Lungs
I am confused! I have learnt
that an artery always
carries oxygen-rich blood. 
Pulmonary
artery
Pulmonary
vein
Fig. 7.3  Schematic diagram of circulation
Blood Donation
Hundreds of people die due to
unavailability of blood. Voluntary
blood donation is harmless and
painless and can save precious lives.
Blood can be donated at hospitals and
other places authorised by the
government. Donated blood are stored
with special care in Blood Banks.
Reprint 2024-25
TRANSPORTATION IN ANIMALS AND PLANTS 73
makes your fist. Your heart is roughly
the size of your fist.
What will happen if the blood rich in
oxygen and the blood rich in carbon
dioxide mix with each other? To avoid
this from happening, the heart has four
chambers. The two upper chambers are
called the atria (singular: atrium) and
the two lower chambers are called the
ventricles (Fig. 7.4). The partition
between the chambers  helps to avoid
Paheli wonders which side of
the heart will have oxygen-rich
blood and which side will have
carbon dioxide-rich blood.
Fig. 7.4  Sections of human heart
Vena Cava
Right atrium
Right ventricle
Partition completely
separating the two
halves
Left atrium
Left ventricle
Pulmonary artery
Pulmonary vein
mixing up of blood rich in oxygen with
the blood rich in carbon dioxide.
To understand the functioning of the
circulatory system, start from the right
side of the heart in Fig. 7.3 and follow
the arrows. These arrows show the
direction of the blood flow from the heart
Aorta
Reprint 2024-25
SCIENCE 74
to the lungs and back to the heart from
where it is pumped to the rest of the
body.
Heartbeat
The walls of the chambers of the heart
are made up of muscles. These muscles
contract and relax rhythmically. This
rhythmic contraction followed by its
relaxation constitute a heartbeat.
Remember that heartbeats continue
every moment of our life. If you place
your hand on the left side of your chest,
you can feel your heartbeat. The doctor
feels your heartbeats with the help of
an instrument called a stethoscope.
A doctor uses the stethoscope as a
device to amplify the sound of the heart.
It consists of a chest piece that carries a
sensitive diaphragm, two ear pieces and
a tube joining the parts. Doctors can
get clues about the condition of your
heart by listening through a
stethoscope.
Let us construct a model of a
stethoscope with the materials that are
available around us.
Activity 7.2
Take a small funnel of 6–7 cm in
diameter. Fix a rubber tube (50 cm long)
tightly on the stem of the funnel. Stretch
a rubber sheet (or a balloon) on the
mouth of the funnel and fix it tightly
with a rubber band. Put the open end
of the tube on one of your ears. Place
Table 7.2 Heartbeat and pulse rate
Name of student While resting After running (4–5 minutes)
Heartbeat Pulse rate Heartbeat Pulse rate
Fig. 7.5  Instrument to hear heartbeat
 (a) Stethoscope (b) Model of
stethoscope
Chest Piece
Ear Piece
Tube
Reprint 2024-25