Bạn đang xem: Pituitary là gì
What is the pituitary gland?
The pituitary glvà is a tiny pea-sized endocrine gland located in a bony cavity in the base of the brain. Endocrine glands secrete hormonal substances into lớn the body’s bloodstream.
The pituitary gland plays a major role in regulating a wide range of biological functions. It secretes hormones involved in:MetabolismGrowthBlood pressureSexual maturation & function
Blood vessels connect the pituitary gl& to lớn a part of the brain known as the hypothalamus. The brain tells the pituitary khổng lồ increase or decrease the secretion of certain hormones.
Sometimes the pituitary is called the “master gland” because it controls the activity of other endocrine glands. The pituitary gland consists of 3 parts: the anterior, intermediate, và posterior lobes.
The anterior lobe, which makes up about 80% of the gland, secretes these hormones:Adrenocorticotropic hooc môn (ACTH) causes the adrenal glands to produce steroid hormones, especially cortisol.Growth hormone (GH) regulates the body’s growth, metabolism, & composition.Thyroid stimulating hormone (TSH) causes the thyroid glvà to lớn produce hormones.Gonadotropins — luteinizing hormone (LH) và follicle stimulating hooc môn (FSH) — cause the ovaries & testes lớn secrete sex hormones involved in reproduction.Prolactin stimulates milk production in women who have sầu given birth.
The intermediate lobe secretes only 1 hormone:Melanocyte-stimulating hormone affects skin pigmentation.
The posterior lobe stores and lets out 2 hormones that are produced by the hypothalamus:Antidiuretic hormone (ADH) regulates water & electrolyte balance.Oxytocin is involved in uterine contractions during childbirth and the production and release of breast milk.
What happens when the pituitary gl& becomes overactive?
When the pituitary glvà is overactive, it secretes excessive amounts of some hormones, usually due to the presence of a benign (noncancerous) tumor. Overactivity of the pituitary glvà is called hyperpituitarism.
Several disorders related khổng lồ an overactive pituitary gl& can occur. These include:
Cushing’s syndrome (hypercortisolism): If the pituitary gl& secretes too much ACTH, the adrenal glands may release too much cortisol. Cortisol regulates the metabolism of proteins, fats, and carbohydrates. It is also involved in the body’s inflammatory và immune responses. Symptoms of Cushing’s disease may include:Accumulation of fat in the upper body.Excessive sầu facial hair in women.Pink or purplish stretch marks on the abdomen.Tendency to lớn bruise easily.Bones may become fragile & tover to lớn break more easily.
Acromegaly: This disorder is caused by secretion of excessive amounts of growth hormone (GH) in adults. Acromegaly can cause:Hands and feet khổng lồ grow.Change in facial structure — jaw và brow may stick out and the nose, tongue, & lips may get bigger.Skin becoming thiông chồng, coarse, & oily.Irregular periods in women và erectile dysfunction in men.Increased risk for high blood pressure, diabetes, heart attaông xã, & certain types of cancer.
In children and adolescents, excessive levels of growth hooc môn can result in a condition called gigantism. Children with this condition may have unusually long arms and legs & may grow to lớn heights of 7 to lớn 8 feet or more.
Prolactinoma: A tumor on the pituitary known as a prolactinoma may cause the glvà to lớn secrete too much prolactin. High levels of prolactin can disrupt normal reproductive functions in men and women by interfering with hormones produced by the testes và ovaries.
A prolactinoma can cause women who are not pregnant or nursing to lớn experience tenderness of the breasts & start khổng lồ produce breast milk (galactorrhea). Their menstrual periods may become irregular or might stop altogether. Women may become infertile or thua thảm interest in having sex. Having intercourse may be painful due to vaginal dryness.
For men, the most common symptom of prolactinoma is erectile dysfunction. Men also may experience a decrease in or loss of sex drive, lower fertility, or loss of energy. In rare cases, men may secrete milk from their breasts or, when the prolactinoma is large, blindness or difficulty seeing can occur.
Hyperthyroidism: If the pituitary adenoma causes overproduction of thyroid stimulating hormone (TSH), the thyroid gland will become hyperactive. Symptoms may include:Nervousness.Rapid or irregular heartbeat.Weight loss.Fatigue.Muscular weakness.
How common is an overactive sầu pituitary?
Small benign pituitary tumors (adenomas) are fairly comtháng. They may be either secreting (releasing excess amounts of hormones) or non-secreting and bởi vì not cause any symptoms. Prolactinomas are the most common type of pituitary tumors, occurring in about 1 out of 10,000 people. They are more common in women than in men.
Acromegaly is a very rare disorder that occurs in only about 3 out of 1 million people each year. It generally is diagnosed in adults age 40 to lớn 45.
Cushing’s syndrome is a relatively rare disorder that occurs mainly in adults from age đôi mươi khổng lồ 50 years old. When the syndrome is caused by an adenoma, it is about 5 times more comtháng in women than in men.