Question

According to one of the theories of ageing, the decline and disappearance of which gland by late middle age is the primary cause of ageing?

• A. Thyroid
• B. Parathyroid
• C. Thymus
• D. Posterior lobe of pituitary

Answer 1

Answer: (C)

Thymus

A. Thyroid gland is situated between the trachea and larynx in the neck and secretes thyroxine hormone which increases oxygen consumption by metabolically active tissues.

B. Parathyroid gland is present in the form of four small pouches which are embedded in the posterior surface of lobes of thyroid gland. This gland secretes parathormone which increases calcium reabsorption from the bones and causes mobilisation of calcium in the blood.

C. Thymus gland is associated with the development of immune system and present on the dorsal side of heart. This gland shows maximum development in children during puberty and by the age of 70, it becomes a tiny structure.

D. Posterior lobe of pituitary is known as neurohypophysis and secretes oxytocin and vasopressin hormone.

Hence, disappearance of thymus gland is primary cause of ageing because immune system of body is affected due to retardation of thymus gland leading to weak immunity.

So, the correct answer is 'Thymus'.