Question

MSH stimulated in man by which part of the pituitary.
(a) Anterior pituitary
(b) The dorsal lobe of the pituitary
(c) The posterior lobe of the pituitary
(d) Intermediate lobe of the pituitary

Answer 1

Hint: The small zone present in between the adenohypophysis and neurohypophysis which is considered as a part of anterior pituitary secretes melanocyte-stimulating hormone(MSH).

Complete answer:
The pituitary gland is an endocrine gland associated with the brain which is mainly divided into two lobes: anterior pituitary lobe, posterior pituitary lobe, and the gap between the anterior and posterior lobes there is a small space called an intermediate lobe. It is called pars intermedia that secretes only one hormone called melanocyte-stimulating hormone(MSH). Pars intermedia is almost merged with Pars digitalis.

Additional Information:
 - Hypophysis or pituitary gland is a small round body that is unpaired located immediately beneath the hypothalamus, attached by a stalk called the infundibulum.
- Anatomically it is divided into the anterior pituitary (pars distalis) and posterior pituitary. Between these two lobes, there is a small zone called the pars intermedia. It is the part of the anterior pituitary in man, as it is almost fused with the anterior lobe.
- Anterior pituitary secretes hormones such as growth hormone, prolactin, thyroid-stimulating hormone, adrenocorticotropic hormone, follicle-stimulating hormone, luteinizing hormone.
- Melanocyte-stimulating hormone(MSH) is the only hormone secreted by Pars intermedia
- Posterior pituitary secretes vasopressin and oxytocin.
- Melanocyte-stimulating hormone role is not significant in humans but it is expected for the darkening of hair by increasing the melanin.
So, the correct answer is ‘Intermediate lobe of the pituitary’

Note: Another name for the posterior pituitary is neurohypophysis and the anterior pituitary is adenohypophysis.
The master control center of the body is the hypothalamus that controls the secretion of the pituitary gland which is located just below the thalamus of the diencephalon.