Welcome to 2 minute neuroscience, where I simplistically explain neuroscience topics
in 2 minutes or less. In this installment I will discuss the hypothalamus and pituitary
The hypothalamus is a small region situated directly above the brainstem. It is made up
of a collection of nuclei with a variety of functions, but in general the hypothalamus
is involved in controlling the two H’s: homeostasis and hormones. Homeostasis is a
term used to describe the maintenance of balance or stability in a biological system. The hypothalamus
can maintain homeostasis either by exerting direct influence over the autonomic nervous
system, or by causing the release of hormones. The hypothalamus manipulates hormone release
primarily by controlling the pituitary gland.
The pituitary gland is a hormone-secreting gland that sits just below the hypothalamus.
It is sometimes called the “master gland” because it not only secretes many extremely
important hormones but it also regulates the activity of other hormone-secreting glands
throughout the body. The pituitary gland consists of two lobes, called the anterior and the
posterior pituitary. The anterior pituitary is responsible for the release of a number
of hormones that have widespread effects throughout the body. They include growth hormone, which
is involved with growth, follicle-stimulating hormone, which plays a role in development
and reproduction, luteinizing hormone, which is essential to testosterone production and
reproduction, adrenocorticotropic hormone, which is involved with the stress and fear
responses, thyroid stimulating hormone, which is important to healthy metabolism, and prolactin,
which promotes milk production in females. The release of these hormones is controlled
by the hypothalamus, which sends signals in the form of releasing hormones to tell the
anterior pituitary when to secrete its hormones.
The posterior pituitary also secretes two hormones, but does not synthesize them. Instead,
they are synthesized by the hypothalamus and then sent to the posterior pituitary for release
into the bloodstream. The names of these hormones are: oxytocin and vasopressin. Oxytocin has
important roles in facilitating childbirth and lactation, but is also thought to have
a role in compassion and social bonding. Vasopressin's main functions are to control urine output
and regulate blood pressure.