The Pituitary Gland - Overview
What is the Pituitary gland?
The pituitary gland (also known as the Hypophysis) is approximately the size of a pea and is located at the base of the brain, just below the hypothalamus. It is a highly vascularised tissue and it sits within a cativity known as the sella turcica. The gland is part of the endrocrine system. The pituitary controls the secretion of many hormones and it can also influence the activity of other glands within the endrocrine system. For this reason it is often also known as the 'master gland'.
In humans this gland is composed of 2 separate lobes; the anterior and postieror. The diagram below shows which hormones are secreted from each region
The anterior pituitary
This is glandular tissue and is responsible for secreting 6 different peptide hormones. These hormones are secreted under the control of releasing hormones from the hypothalamus, Once secreted, these hormones enter the blood stream and act on various target tissues. For 4 of the anterior pituitary hormones ( TSH, ACTH, LH and FSH) their target is other endocrine tissue i.e they activate cells which synthesis other hormones.
(image courtesy of http://www.pituitarysociety.org/images/pgdiag3.gif)
The posterior pituitary
This lobe of the pituitary is actually an extension of the brain, unlike the anterior part. It is also responsible for the secretion of peptide hormones; oxytocin and Vasopressin (also known as ADH). Again, like the anterior pituitary, the release of these hormones is ultimately controlled by the hypothalamus.
The pituitary and the hormones it secretes, work (often together) to help regulate the following body processes:
- Blood pressure
- The stimulation of uterine contractions during childbirth
- production of breast milk
- Sex organ function in male and females
- Thyroid gland
- Osmolarity of the blood