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2-Minute Neuroscience: Hypothalamus & Pituitary Gland

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

gland.

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.