Endocrine System


 
 
Concept Explanation
 

Endocrine System

Endocrine system: The endocrine system consists of a collection of bag-like structures called glands. These glands are located at specific places inside our bodies and release chemical substances called hormones. The major glands that make up the human endocrine system are pituitary, thyroid, adrenals, pancreas, ovaries, and testes. A diagrammatic representation of the human endocrine system is shown.

 1.    Pituitary gland

Location: base of the brain

Hormones secreted: 1.  Thyroid stimulating hormone (TSH),  2.  Growth hormone (GH)

Hormone action : TSH :  Its principal function is to monitor and regulate the activity of other glands.  

                             GH : GH stimulate linear growth in children and helps to maintain bone and other tissues in adult.

 2. Pineal gland : 

       Location : Deep in the brain 

       Hormone secreted : melatonin and serotonin 

       Hormone action  : Melatonin hormones regulate night and day cycles or sleep-wake cycles.

                                       Serotonin  stabilizes our mood, feelings of well-being, and happiness. 

3.    Thyroid gland 

Location: Base of the throat

Hormones secreted: Thyroxine  

Hormone action : Thyroxine plays a crucial role in heart and digestive function, metabolism, brain development, bone health and muscle control.

4. Thymus gland 

Location :  Beneath the breastbone at the level of the heart

Hormone secreted : Thymosin hormone

Hormone action : Produce and process T lymphocytes.

5.    Adrenal gland 

Location: Near the kidneys

Hormones secreted: Adrenaline 

Hormone action : Adrenaline is often known as the fight or flight hormone because it prepares the body to act, especially when the body encounters stress.

6.    Pancreas 

Location: Near the liver 

Hormones secreted: insulin, glucagon

Hormone action : Insulin acts to lower blood sugar, and glucagon, which acts to raise blood sugar.

7.    Testis:  (In males: two in number)

Location: Male genital organs

Hormones secreted:  Testosterone

Hormone action : Testosterone controls the development of secondary sexual characters in males such as facial hair, beard, moustaches etc. It stimulates spermatogenesis (formation of sperm).

8. Ovaries (in female; two in number)

Location : Pelvic region

Hormones secreted:  Estrogen and progesterone

Hormone action : Estrogen stimulates the growth and development of female secondary sex organs and female secondary sexual characters (such as development of breasts). Progesterone play an important role in regulation of menstrual cycle and pregnancy.

Question: Why pituitary gland is also called as master gland of the endocrine system?

Solution : Pituitary gland is also called as master gland of the endocrine system because:

(i) The hormones it secretes play an active part in controlling the functions of other endocrine glands.

(ii) Its job is to receive messages about the need for a particular hormone and to secrete the hormones that cause the manufacture and release of the hormones.

                

 

 

Sample Questions
(More Questions for each concept available in Login)
Question : 1

Which of the following is correct among the following :

(a) Pituitary gland is located at the base of the brain.

(b) Thyroid gland secrete serotonin hormone.

(c) Adrenal gland present near kidneys.

(d) Testes present in male and females.

Right Option : D
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Question : 2

Estrogens are secreted by _______________

Right Option : B
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Question : 3

Consisder the following statements and select the option which correctly identifies true (T) and false (F) ones.

  1. Reproductive life of woman lasts from menarche to menopause.
  2. In females, the uterus wall thickens to receive the embryo.
  3. Estrogen is released by testes at the onset of puberty.
  4. Hormones secreted by adrenal glands stimulate testes and ovaries to produce their hormones.
Right Option : C
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Explanation
 
 
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