The pituitary gland (brain appendage) - is a small (weighing only 0.5-0.6 g) endocrine gland, located at the bottom of the skull in the Turkish sadd

Hypophysis [Pituitary gland]

The pituitary gland (brain appendage) — is a small (weighing only 0.5-0.6 g) endocrine gland, located at the bottom of the skull in the Turkish saddle. The pituitary gland is connected to the brain by a stalk. It consists of two parts: the front — glandular pituitary gland, or adenohypophysis, and the rear — neurohypophysis.

Posterior pituitary function is in secretion of two hormones, which are produced by nerve cells of the hypothalamus, accumulated in neurohypophysis and secreted into the bloodstream as needed. The first of them is antidiuretic hormone. It increases blood pressure, so it has the second name — vasopressin. The second hormone (oxytocin) directs contractions of the uterus during labor and milk production by breasts.

The secretory function of the adenohypophysis is carried out under the influence of neurohormones that are produced by hypothalamic neurons. Anterior lobe of the pituitary produces eight hormones. Two of them — the growth hormone (somatotropin) and melanotropin — are the effector hormones. Other hormones — are regulators that control the activity of the thyroid and sex and the adrenal glands. Taken from http://worldofschool.org

Growth hormone effects on growth processes and on cells division in the body. Bone and cartilage are especially sensitive to it. For first, it increases the linear dimensions of the body. If as a result of some disorders in childhood pituitary gland produces too much growth hormone — gigantism develops (height can reach 280 cm). With its lack in childhood — dwarfism develops. Smallest woman had a height of 59 cm, and a man — 67 cm. After 21, formation of the growth hormone ceases. If an adult increases the excretion of this hormone, acromegaly develops. As a result of this disease increases not the size of the whole body, but only some of its parts — the nose, chin, tongue, hands, feet, because of this human becomes ugly.

Melanotropin affects the pigment cells of the skin, stimulating the formation of melanin pigment by which the skin darkens under sunlight.

Hit in the head may result gigantism or acromegaly, disfigure the body and face of a human for a lifetime.

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Questions:
  • Explain the features of the structure and function of the pituitary.

  • Find out the mechanism of pituitary hormones action.

  • What causes an abnormality of pituitary function.

  • What part of the brain is both a part of the central nervous system and the main regulator of the endocrine glands?