Pituitary Gland

Pituitary Gland

The structure indicated is the pituitary gland.

The pituitary gland is an endocrine gland located at the base of the brain, and lies within the sella turcica of the sphenoid bone, which is a saddle-shaped depression that encases and surrounds the pituitary gland­. The deepest part of the sella turcica is known as the hypophyseal fossa, anteriorly is the tuberculum sellae, and posteriorly is the dorsum sellae. The sella turcica itself is covered by a fold of dura known as the diaphragma sellae. The pituitary gland releases several hormones which are responsible for the control and regulation of several organs systems and bodily functions

The pituitary gland itself extends inferiorly from the hypothalamus and consists of three parts:

  1. Anterior pituitary (adenohypophysis)
  2. Intermediate lobe
  3. Posterior pituitary (neurohypophysis)

The anterior pituitary originates from oral ectoderm, whereas the posterior pituitary originates from neuroectoderm; the anterior pituitary is glandular, whereas the posterior pituitary consists of neural tissue. The release of hormones from the anterior pituitary is regulated by releasing hormones from the hypothalamus via the hypothalamo-hypophyseal portal system.

The anterior pituitary consists of three parts:

  1. Pars tuberalis
  2. Pars intermedia
  3. Pars distalis

The anterior pituitary releases the following hormones:

  • Leutenising hormone (LH)
  • Follicle-simulating hormone (FSH)
  • Human growth hormone (GH)
  • Thyroid stimulating hormone (TSH)
  • Adrenocorticotropic hormone (ACTH)
  • Prolactin (PRL)

The intermediate lobe secretes melanocyte-stimulating hormone (MSH)

The posterior pituitary is an extension of the hypothalamus and is comprised of neural tissue that extends directly from the hypothalamus as collections of axonal fibres. The posterior pituitary secretes the following hormones:

  • Antidiuretic hormone (ADH)
  • Oxytocin

Learn more about the anatomy of the brain in this tutorial.