Question

For the following list of disorders describe the defect, including the hormone and gland that is not functioning properly.

            a.         SIADH

            b.         Diabetis Insipidus

            c.         Acromegaly

            d.         Grave’s Disease

            e.         Cushing’s Disease

Answer 1

A. SIADH (Syndrome of inappropriate antidiuretic hormone secretion).
• ADH hormone is synthesized by hypothalamus and secreted by posterior pituitary gland. This hormone helps in water retention in kidney.
• In SIADH, increased ADH causes excess water retention and it leads to increased blood volume and decreased urine output. It causes symptoms like anorexia, nausea and vomiting.
• This may be caused by brain damage, various infections like pneumonia, drugs like morphine, malignancy etc. These conditions give feedback to hypothalamus for increased ADH synthesis and release.

B. Diabetes insipidus :-
• This is associated with hormone ADH or vasopressin.
• If ADH secretion is decreased by posterior pituitary gland then this is called as central diabetes insipidus.
• When ADH secretion is in adequate amount but kidneys do not respond to ADH then it is called as nephrogenic diabetes insipidus.
• In this disease, due to lack of functioning of ADH hormone, excessive fluid is lost from kidneys and causes polydipsia and polyuria condition. This may lead to dehydration.
• This disease may caused by injury in hypothalamus or pituitary gland and it may aslo genetic.

C. Acromegaly :-
• Caused by increased growth hormone secretion by pituitary gland.
• These may be may tumour in pituitary gland which leads to increased secretion of growth hormone.
• Increased growth hormone increases bone and muscle growth and causes enlargement of face, hands and feet.

D. Grave's disease :-
• This is caused by excess secretion of thyroid hormone from thyroid gland.
• This is an autoimmune disease, in which antibodies increases secretion of thyroid hormone.
• Increased thyroid hormone causes increased metabolic activities in body and causes symptoms like anxiety, heat sensitivity, weight loss, and headache.

E. Cushing’s Disease :-
• This is caused by increased levels of ACTH ( Adrenocorticotropic hormone) from pituitary gland. This leads to increased secretion of cortisol from adrenal cortex.
• This is caused by cancer in pituitary gland cells. (** Cushing's syndrome is also a similar condition but that is caused by cancer in adrenal cortex).
• Increased cortisol causes - high blood pressure, muscle weakness, weight gain, changes in mood etc.

* Cushing's disease = increased ACTH and increased cortisol.
Cushing's syndrome = increased cortisol.