As small as a hazelnut, it has a huge effect: the pituitary gland regulates the most diverse functions in the body through hormones - from body growth and milk production after childbirth to urine excretion. Here you can find out more about the control center of our hormone system.
What does the pituitary look like and where is it?
The Greek name pituitary literally means "the down-hanging plant". This pretty well describes their anatomical position: the pituitary "hangs under" our brain. It sits on the Sella turcica (Turkish Saddle), a depression of the base of the skull in the middle of our skull, at the level of the nose and ears. She is one-inch tall and about one gram light.
The pituitary gland consists of the anterior pituitary gland (HVL, adenohypophysis) and the posterior pituitary gland (HHL, neurohypophysis). The region between the two lobes is called Pars intermedia. Via the pituitary stalk, the pituitary gland is connected to the hypothalamus, a part of the diencephalon.
The neurohypophysis is a part of the brain, namely a protuberance of the diencephalon. The adenohypophysis is a hormone gland. Hypothalamus and pituitary together form an important functional unit.
What is the function of the pituitary gland?
The anterior pituitary produces hormones, the posterior pituitary is the location for hormones that the hypothalamus makes. The Pars intermedia is functionally part of the HVL as it also produces a hormone.
What happens in the anterior pituitary?
The adenohypophysis produces the following hormones:
- Adrenal cortical stimulating (adrenocorticotropic) hormone (ACTH)
- the growth hormone (also: growth hormone = GH or somatotropin = STH)
- thyroid stimulating hormone (TSH)
- the follicle stimulating hormone (FSH)
- the luteinizing hormone (LH)
ACTH stimulates the adrenal glands to form cortisone, aldosterone and androgens.
GH or STH promotes growth by providing energy: Liver and adipose tissue release fats and sugars. In addition, the liver stimulates bone growth. In addition, GH promotes protein formation.
TSH acts on the thyroid so that it produces more hormones.
FSH and LH stimulate the production of sex hormones in testes and ovaries, respectively. In the case of the woman, the oocytes mature and trigger ovulation; in men, they are responsible for sperm formation.
Prolactin promotes breast growth and milk production while inhibiting ovulation. However, one should not rely entirely on this natural form of "contraception" in nursing mothers.
The activity of the adenohypophysis is controlled by the hypothalamus, which releases "control hormones": inhibiting hormones slow down production, releasing hormones promote them. Also "feedback" of the respective target organs influence the function of the HVL.
What happens in the posterior pituitary gland?
The HHL consists of nerve cells whose heads sit in the hypothalamus, which is why it is also called neurohypophysis. It serves as a storage site for two hormones that are formed in the hypothalamus and pass through the nerve cells in the posterior pituitary glands:
The antidiuretic hormone (ADH, also vasopressin or adiuretine) acts in the kidneys on water absorption. Urinary excretion diminishes and water is retained in the body. The urine is more concentrated, which is noticeable in color and smell. In addition, ADH can constrict blood vessels and increase blood pressure.
Oxytocin induces labor in pregnant women by contracting the muscles of the uterus. In addition, it provides after the birth for the "milk injection".
What does the Pars intermedia do?
Pars intermedia produces melanocyte-stimulating hormone (MSH, melanotropin). MSH stimulates the production of melanin in our skin pigment cells (melanocytes), which protects us from the sun's harmful UV radiation. Additionally, MSH controls our appetite and our sexual arousal.