Page 96 - NCERT Science Class 10 English Medium

ou Know? n If the alveolar surface were spread out, it would cover about 80 m . How much
2
do you think the surface area of your body is? Consider how efficient exchange
of gases becomes because of the large surface available for the exchange to take
place.
Do Y n If diffusion were to move oxygen in our body, it is estimated that it would take 3
years for a molecule of oxygen to get to our toes from our lungs. Aren’t you glad
that we have haemoglobin?

Q U E S T I O N S

1. What advantage over an aquatic organism does a terrestrial organism
have with regard to obtaining oxygen for respiration?
2. What are the different ways in which glucose is oxidised to provide
energy in various organisms? ?
3. How is oxygen and carbon dioxide transported in human beings?
4. How are the lungs designed in human beings to maximise the area for
exchange of gases?

5.4 TRANSPORTANSPORTAATIONTION
5.4 TRANSPORTATION
TR
5.4 TRANSPORTATIONTION
5.4
5.4 TRANSPORTA
5.4.1 Transportation in Human Beings
5.7
Activity 5.75.7
Activity
Activity
Activity 5.7
Activity 5.7
n Visit a health centre in your locality and find out what is the
normal range of haemoglobin content in human beings.
n Is it the same for children and adults?
n Is there any difference in the haemoglobin levels for men and
women?
n Visit a veterinary clinic in your locality. Find out what is the normal
range of haemoglobin content in an animal like the buffalo
or cow.
n Is this content different in calves, male and female animals?
n Compare the difference seen in male and female human beings
and animals.
n How would the difference, if any, be explained?

We have seen in previous sections that blood transports food, oxygen
and waste materials in our bodies. In Class IX, we learnt about blood
being a fluid connective tissue. Blood consists of a fluid medium called
plasma in which the cells are suspended. Plasma transports food, carbon
dioxide and nitrogenous wastes in dissolved form. Oxygen is carried by
the red blood corpuscles. Many other substances like salts, are also
transported by the blood. We thus need a pumping organ to push blood
around the body, a network of tubes to reach all the tissues and a system
in place to ensure that this network can be repaired if damaged.

Life Processes 91

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