Page 115 - NCERT Science Class 10 English Medium

(a) (b)

Figure 6.7 Endocrine glands in human beings (a) male, (b) female

Let us examine some examples to understand how hormones help
in coordinated growth. We have all seen salt packets which say ‘iodised
salt’ or ‘enriched with iodine’. Why is it important for us to have iodised
salt in our diet? Iodine is necessary for the thyroid gland to make
Do You Know? thyroxin hormone. Thyroxin regulates carbohydrate, protein and fat
metabolism in the body so as to provide the best balance for growth.
Hypothalamus plays Iodine is essential for the synthesis of thyroxin. In case iodine is deficient
an important role in in our diet, there is a possibility that we might suffer from goitre. One
the release of many of the symptoms in this disease is a swollen neck. Can you correlate
hormones. For this with the position of the thyroid gland in Fig. 6.7?
example, when the Sometimes we come across people who are either very short (dwarfs)
level of growth or extremely tall (giants). Have you ever wondered how this happens?
hormone is low, the Growth hormone is one of the hormones secreted by the pituitary. As
hypothalamus its name indicates, growth hormone regulates growth and development
releases growth of the body. If there is a deficiency of this hormone in childhood, it
hormone releasing leads to dwarfism.
factor which You must have noticed many dramatic changes in your appearance
stimulates the as well as that of your friends as you approached 10–12 years of age.
pituitary gland to These changes associated with puberty are because of the secretion of
release growth testosterone in males and oestrogen in females.
hormone. Do you know anyone in your family or friends who has been advised
by the doctor to take less sugar in their diet because they are suffering
from diabetes? As a treatment, they might be taking injections of insulin.
This is a hormone which is produced by the pancreas and helps in
regulating blood sugar levels. If it is not secreted in proper amounts,
the sugar level in the blood rises causing many harmful effects.

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