Page 116 - NCERT Science Class 10 English Medium

If it is so important that hormones should be secreted in precise
quantities, we need a mechanism through which this is done. The timing
and amount of hormone released are regulated by feedback mechanisms.
For example, if the sugar levels in blood rise, they are detected by the
cells of the pancreas which respond by producing more insulin. As the
blood sugar level falls, insulin secretion is reduced.

Activity 6.46.4
Activity
Activity 6.4
Activity 6.4
Activity 6.4
n Hormones are secreted by endocrine glands and have specific functions. Complete
Table 6.1 based on the hormone, the endocrine gland or the functions provided.
Table 6.1 : Some important hormones and their functions

S.No. Hormone Endocrine Gland Functions

1. Growth hormone Pituitary gland Stimulates growth in all organs
2. Thyroid gland Regulates metabolism for body growth
3. Insulin Regulates blood sugar level
4. Testosterone Testes
5. Ovaries Development of female sex organs,
regulates menstrual cycle, etc.
6. Adrenaline Adrenal gland
7. Releasing Stimulates pituitary gland to release
hormones hormones

Q U E S T I O N S

1. How does chemical coordination take place in animals?
2. Why are some patients of diabetes treated by giving injections of insulin? ?
Why is the use of iodised salt advisable?
3. How does our body respond when adrenaline is secreted into the blood?
4.
What you have learnt

n Control and coordination are the functions of the nervous system and hormones
in our bodies.
n The responses of the nervous system can be classified as reflex action, voluntary
action or involuntary action.
n The nervous system uses electrical impulses to transmit messages.
n The nervous system gets information from our sense organs and acts through our
muscles.
n Chemical coordination is seen in both plants and animals.
n Hormones produced in one part of an organism move to another part to achieve
the desired effect.
n A feedback mechanism regulates the action of the hormones.

Control and Coordination 111

2024-25