Question

The diagram given below represents an endocrine gland in the human body. Study the  diagram and answer the following questions:

1. Identify the endocrine gland. Where is it located?
2. Why is the above gland referred to as the ‘Master gland’?
3. Name the hormone which in deficiency causes Diabetes Insipidus. How does this disorder differ from Diabetes Mellitus?
4. Explain the term ‘Hormone’. What is the role of Tropic hormones in the human body?
5. Which lobe of the above gland secretes:
   1. Oxytocin
   2. ACTH
   3. Growth hormone

Answer 1

(i) The endocrine gland represented is the pituitary gland. It is located at the base of the brain, attached to the hypothalamus.

(ii) The pituitary gland is referred to as the ‘Master gland’ because it secretes hormones that regulate and control the activity of other endocrine glands in the body.

(iii) Diabetes Insipidus is caused by the deficiency (hyposecretion) of the Antidiuretic Hormone (ADH), also known as vasopressin. This is secreted by the posterior pituitary.

Diabetes Insipidus differs from Diabetes Mellitus because Diabetes Mellitus is caused by a deficiency of insulin produced by the pancreas, whereas Diabetes Insipidus results from the inability of the kidneys to retain water due to a lack of ADH.

(iv) A hormone is a chemical substance secreted by an endocrine gland directly into the bloodstream that acts as a chemical messenger to regulate various physiological and metabolic activities.

The role of tropic hormones is hormones secreted by the pituitary gland that specifically stimulate and control the activity of other endocrine glands.

(v)

1. Oxytocin: Secreted by the posterior lobe of the pituitary gland.
2. ACTH (Adrenocorticotropic hormone): Secreted by the anterior lobe of the pituitary gland.
3. Growth hormone: Secreted by the anterior lobe of the pituitary gland.