Sunday, September 19, 2021

7. Control and Coordination | Class 10 CBSE | Web Notes | Part 3 | Hormones in Animals

7. CONTROL AND COORDINATION

HORMONES IN ANIMALS (ENDOCRINE SYSTEM)


Electrical impulses can instruct only few tissues to prepare for an activity. So, in animals, there is another way of control & coordination called Endocrine system.


It includes endocrine glands and their secretions called hormones (chemical signals). They can reach all cells and provide wide-ranging changes. E.g. Adrenal glands secretes adrenaline.


Adrenaline prepares body to cope with emergency situations. E.g. E.g. a scary animal such as squirrels prepare to fight or run away. It needs more energy.


Though fighting & running are different, both have some common preparations.


Adrenaline is secreted into blood and carried to different body parts. As a result, the following events occur:

o  Heart beats faster to supply more oxygen to muscles.

o  Blood to the digestive system and skin is reduced by contracting muscles around small arteries in these organs. This diverts the blood to skeletal muscles.

o  Breathing rate increases due to the contraction of diaphragm and rib muscles.


These responses prepare the body to deal with the situation (fighting and running).


The timing and amount of hormone released are regulated by feedback mechanisms. E.g. if the blood sugar level increases, it is detected by cells of pancreas and produce more insulin. As the blood sugar level falls, insulin secretion is reduced.



SOME IMPORTANT HORMONES AND THEIR FUNCTIONS

Endocrine Gland

Hormone

Functions & other info

Hypothalamus

Releasing hormones

Stimulates pituitary gland to release hormones. E.g. growth hormone releasing factor stimulates pituitary gland to release GH.

Pituitary gland

Growth hormone (GH)

Stimulates growth & development of the body.

Dwarfism: Deficiency of GH in childhood.

Gigantism: Overproduction of GH in childhood.

Thyroid gland

Thyroxine

Regulates carbohydrate, protein & fat metabolism for balanced growth.

Iodine is essential for synthesis of thyroxin. Iodised salts provide iodine.

Deficiency of iodine causes goitre. Swollen neck is the main symptom.

Pancreas

Insulin

Regulates blood sugar level.

Deficiency of insulin causes diabetes (sugar level increases).

Such patients are given insulin injections.

Adrenal gland

Adrenaline

Prepares body to cope with emergency situations.

Testes (in male)

Testosterone

Changes during puberty. Development of male sex organs, behaviour etc.

Ovaries (in female)

Oestrogen

Changes during puberty. Development of female sex organs, regulates menstrual cycle, etc.


Select Your Next Topic 👇

👉 Part 1: Animals- Nervous System
👉 Part 2: Coordination in Plants
👉 Part 3: Hormones in Animals



No comments:

Post a Comment