Pituitary: What is it? Structure, Lobes, Function and Associated Problems

Also called the pituitary gland, it controls important bodily functions and the hormonal system.

It is a protrusion at the base of the brain and the size of a pea or cherry, so it is also called “pituitary gland” (in Greek it means “growth attached below”).

The gland is well protected in a small cavity of the bones of the skull, at the level of the nose and in the middle of the head.

The pituitary gland and the hypothalamus , a part of the interbrain, control the involuntary nervous system, which manages the balance of energy, heat and water in the body.

The body temperature, the heartbeat or the amount of urine are regulated in this way, so are sleep, hunger and thirst.

The pituitary gland also produces a series of hormones that control most of the other hormone glands in the body or have a direct effect on specific organs.

Structure

The pituitary gland is made up of four parts:

  • Anterior lobe of the pituitary gland (anterior pituitary gland).
  • Posterior lobe of the pituitary (posterior pituitary).
  • The middle part between both lobes.
  • Pituitary stem, which forms the connection with the brain.

The anterior and posterior lobes work independently of each other. While the posterior lobe is directly connected to the interbrain (hypothalamus), there is no such connection from the anterior part of the pituitary gland, where the hormones are produced.

Anterior lobe

The anterior lobe constitutes approximately three quarters of the total mass of the pituitary gland and is formed by glandular tissue. Here two types of hormones are produced:

  1. Hormones that control other hormonal glands.
  2. Hormones that have a direct effect on the body.

The group of glands that control hormones includes:

  • The thyroid stimulating hormone, which regulates the production of hormones in the thyroid gland.
  • Adrenocorticotropic hormone, which stimulates the adrenal glands to produce hormones.
  • The follicle-stimulating hormone, which regulates the production of hormones in the ovaries and testes.
  • Luteinizing hormone, which also has an effect on the production of hormones in the ovaries and testes.

The group of hormones that has a direct effect includes:

  • Growth hormone, also called somatotropic hormone, which has an effect particularly on the liver and bones, on fat, muscle and many other tissues and organs in the body.
  • Prolactin, which influences the mammary glands and the ovaries.

Hormones are released by the pituitary gland into the bloodstream and then reach the various organs that they have an effect on.

Thyroid stimulating hormone, for example, stimulates the thyroid gland to produce more or less thyroid hormones, depending on how much is needed.

Prolactin stimulates the growth of the breasts at puberty, activates the production of milk in the breasts and suppresses ovulation.

There are two mechanisms that regulate the production of hormones in the anterior lobe:

  1. Liberation or inhibition of hormones produced by the hypothalamus.
  2. Level of hormone in the blood, when the level of thyroid hormones in the body is high enough, the pituitary gland stops producing the hormone that stimulates the thyroid gland.

Posterior lobe

The posterior lobe consists mainly of entangled nerve fibers from the hypothalamus. The posterior lobe stores two different hormones, which are released if necessary: ​​oxytocin has an effect on the uterus and the mammary glands.

Vasopressin, also called antidiuretic hormone, influences the kidney and blood vessels.

In pregnant women, oxytocin causes contractions during delivery, for example. Vasopressin plays an important role in regulating the amount of water in the body .

Intermediate part

In the middle part between the anterior and posterior pituitary glands, there is also tissue that produces a hormone: the melanocyte-stimulating hormone or intermediate, which mainly affects the skin, but also the nerve cells of the brain.

This hormone stimulates the production of melanin in the skin, a pigment that protects against the harmful ultraviolet rays of the sun. It also regulates our appetite and influences the sexual impulse.

Pituitary stem

The pituitary stalk connects the posterior lobe directly with the interbrain, or more precisely, with the hypothalamus.

Function of the pituitary gland

The function of your pituitary gland is twofold, it is essentially the master regulator of a variety of other organs and also secretes hormones that have a generalized effect. Here is a complete list of the hormones produced by the pituitary gland and its function:

  • Adrenocorticotropin: incites the production of cortisol.
  • Thyroid stimulating hormone : stimulates the secretion of thyroid hormone.
  • Antidiuretic hormone : vasopressin, regulates the retention of water by the kidneys.
  • Oxytocin : triggers labor, uterine contractions, and ejection of milk in the nipple.
  • Follicle-stimulating hormone : promotes the production of sperm, activates ovulation.
  • Prolactin : stimulates the production of breast milk, affects the levels of sex hormones of the ovaries and testes.
  • Luteinizing hormone : activates the production of testosterone and estrogen
  • Growth hormone: stimulates growth, maintains a healthy muscle and bone mass, affects the distribution of fat and metabolism.

As you can see, the release of the pituitary hormone plays a vital role in your health and well-being.

Problems of the pituitary gland

The most common cause of pituitary gland problems are tumors, most of which are benign.

Its appearance is quite common and the problem usually involves problems related to pressure, too much hormone secretion (hypersecretion) or too little secretion of a hormone (hyposecretion).

As a result, these problems related to the tumor of the pituitary gland can lead to other hormonal imbalances or effects on health, for example, can be one of the causes of these problems:

Large pituitary tumors can put pressure on the surrounding tissue, causing headaches, vision problems, smell problems, etc.