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Class 10 Class 12

Write short notes on the functions of the following hormones.

(a) Parathyroid hormone (PTH)
(b) Thyroid hormones
(c) Thymosins
(d) Androgens
(e) Estrogens
(f) Insulin and Glucagon.

(a) Parathyroid horomone : 

Parathyroid hormone (PTH) is relesed by the parathyroid glands. It is a peptide hormone. 

Function - The PTH performs the following function:
i. Increases the Ca2+ level in the blood and maintains the calcium balance in the body. 
ii. It acts on bones and stimulates the process of demineralisation. 
iii. It stimulate the reabsorption of the Ca2+ by the renal tubules.
iv. It increases the calcium absorption from the digested food. 

(b)  Thyroid hormones :

Thyroxine/ Tetraiodothyonine (T4) and triiodothyronine (T3) are collectively known as thyroid hoemones. They are secreted by the follicular cells of the thyroid gland and are peptide hormones.

Functions - They perform the following functions.

i. Regulate the basal metabolic rate
ii. Support the red blood cells formation. 
iii. Control the metabolism of carbohydrates, proteins and fats.
iv. Maintain the water and electrolyte balance.
v. Regulate the blood calcium levels.  

(c) Thymosins

Thymosins are released by the thymus gland. They are peptide hormones. 

Functions - They peform the following functions. 

i. Play a major role in the differentiation of T-lymphocytes.
ii. Promote the production of antibodies. 

(d) Androgens 

Androgens are the secreted by the Leydig cells or interstitial cells. Androgens are a group of hormones that consist mainly testosterone. 

Function - They perform the following functions.

i. Regulate the development, maturation and functions of the male accessor sex organs in males.
ii. Stimulate development of secondary sexual characters in males.
iii. Stimulate the process of spematogenesis.
iv. Produce anabolic effect on protein and carbohydrate metabolism.

(e) Estrogens  

Estrogen is secreted by ovary. It is a steroid hormone synthesied by ovarian follicles. 

Functions - They perform the following functions:

 Stimulate the growth and activity of female secondary sex organs. and regulate the female sexual behaviour

(f) Insulin and Glucagon

These are released by the pancreas. The insulin hormone is synthesized by the beta-cells and the glucagon is synthesized by the alpha-cells. 

Functions : They perform the following functions. 

i. They maintain the glucose homeostasis.
ii. The glucagon acts on the liver cells and result in glycogenolysis and thus in the increased glucose levels in the blood. It also reduces the glucose uptake and utilisation. 
iii. Insulin decreases the blood glucose level and enhaces cellular glucose uptake and utilisation. 


What is goitre?

Goitre is the condition in the the thyroid gland is enlarged and the neck portion becomes swollen .It is due to the deficiency of iodine in our diet which results in the less production and secretion of the thyroid hormones that is hypothyroidism.

Name the cells that the thyroid gland is composed of.

The thyroid gland is composed of the following :
i. Follicles
ii. Stromal tissue

Name the largest endocrine gland.

Thyroid gland.

Why is the Parathyroid hormone called hypercalcemic hormone?

PTH or parathyroid hormone is also called hypercalcemic hormone as it increase the calcium level in the blood.

Name the endocrine gland which is H shaped.

Thyroid gland.