Understand the different functions of pituitary gland

Today, let's discuss the functions of the hypothalamus and the pituitary gland. The information can be handy for the upcoming exams.

Hyderabad: The article is in continuation to the last article about chemical coordination and integration in the human body. Today, let’s discuss the functions of the hypothalamus and the pituitary gland. The information can be handy for the upcoming exams.

• However, the hormones produced by hypothalamus are of two types, the releasing hormones (which stimulate secretion of pituitary hormones) and the inhibiting hormones (which inhibit secretions of pituitary hormones).

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• For example, a hypothalamic hormone called Gonadotrophin releasing hormone (GnRH) stimulates the pituitary synthesis and release of gonadotrophins. On the other hand, somatostatin from the hypothalamus inhibits the release of growth hormone from the pituitary.
• These hormones originating in the hypothalamic neurons pass through axons and are released from their nerve endings.
• These hormones reach the pituitary gland through a portal circulatory system and regulate the functions of the anterior pituitary.
• The posterior pituitary is under the direct neural regulation of the hypothalamus.

Pituitary Gland
•The pituitary gland is in a bony cavity called sella tursica and is attached to hypothalamus by a stalk.
•It is divided anatomically into an adenohypophysis and a neurohypophysis.
• Adenohypophysis consists of two portions, pars distalis and pars intermedia.

•The pars distalis region of pituitary, commonly called anterior pituitary, produces growth hormone (GH), prolactin (PRL), thyroid stimulating hormone (TSH), adrenocorticotrophic hormone (ACTH), luteinizing hormone (LH) and follicle stimulating hormone (FSH).
• Pars intermedia secretes only one hormone called melanocyte stimulating hormone (MSH).

•However, in humans, the pars intermedia is almost merged with pars distalis.
• Neurohypophysis (pars nervosa) also known as posterior pituitary, stores and releases two hormones called oxytocin and vasopressin, which are actually synthesised by the hypothalamus and are transported axonally to neurohypophysis.

•Over-secretion of GH stimulates abnormal growth of the body leading to gigantism and low secretion of GH results in stunted growth resulting in pituitary dwarfism. Excess secretion of growth hormone in adults especially in middle age can result in severe disfigurement (especially of the face) called Acromegaly, which may lead to serious complications, and premature death if unchecked. The disease is hard to diagnose in the early stages and often goes undetected for many years, until changes in external features become noticeable.

To be continued…
By

Dr. Modala Mallesh

Subject Expert
Palem, Nakrekal, Nalgonda
9989535675