Endocrine System, associated organs and tissues of the body that collectively release substances known as hormones. Endocrine organs are also known as ductless glands because their secretions are released directly into the bloodstream, whereas exocrine

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Endocrine System, associated organs and tissues
of the body that collectively release substances
known as hormones. Endocrine organs are also
known as ductless glands because their secretions
are released directly into the bloodstream,
whereas exocrine glands discharge their
secretions on external or internal surface
tissues of the skin, the lining of the stomach,
or of the lining of the pancreatic ducts.
Hormones released by the endocrine glands
regulate the growth, development, and function of
many tissues and coordinate the metabolic
processes within the body. Endocrinology is the
study of the endocrine glands, the hormonal
substances produced by these glands, their
physiological effects, and the disorders and
diseases that result from their malfunction.
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PITUITARY GLAND The pituitary gland, or
hypophysis, consists of three lobes the anterior
lobe the intermediate lobe, which in primates is
present for only a short part of the lifespan
and the posterior lobe. It is situated at the
base of the brain and has been called the master
gland. The anterior and the posterior lobes of
the pituitary secrete different hormones
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1. Adrenocorticotrophic hormone, or ACTH, which
stimulates the adrenal cortex 2.
Thyroid-stimulating hormone, or thyrotrophin,
known as TSH, which controls the thyroid gland
2. Follicle-stimulating hormone (FSH) and
Luteinizing hormone (LH), which stimulate the sex
glands and Prolactin, which, with other special
hormones, influences milk production of the
mammary gland. In addition, the anterior
pituitary is the source of growth hormone, also
called Somatotrophin.
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Secretion of three anterior pituitary hormones is
under regulation of the hypothalamus
Thyrotrophin secretion is stimulated by
Thyrotrophin-releasing factor (TRF), and
luteinizing-hormone secretion by
Luteinizing-hormone releasing hormone (LHRH).
Dopamine made in the hypothalamus usually
inhibits the release of prolactin by the anterior
pituitary. Furthermore, release of growth hormone
is inhibited by Somatostatin, which is also made
by the pancreas. This means that the brain also
functions as a gland.
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Adrenal secretions regulate the salt and water
balance of the body, influence blood pressure,
affect lymphatic tissue, influence the mechanisms
of the immune system, and regulate carbohydrate
and protein metabolism.
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THYROID GLAND

• The thyroid is a two-lobed gland situated in the
  neck. The thyroid hormones Thyroxin and
  Triiodothyronine increase oxygen consumption and
  stimulate the rate of metabolism, regulating the
  growth and maturation of body tissues and
  affecting physical and mental alertness. The
  thyroid also secretes a hormone known as
  Calcitonin, which lowers the levels of calcium
  and phosphate in the blood and inhibits bone
  resumption.

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A fatal thyroid disease
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Parathyroid gland

• Parathyroid Gland, any of a group of glandular
  cell aggregations located in the neck region
  close to the thyroid gland . In humans, four such
  clumps are present as distinct, yellowish-brown,
  encapsulated organs.
• The parathyroid glands secrete Parathormone, a
  hormone which controls the concentration of
  calcium (calcium ion) and phosphorus (phosphate)
  in the blood. Calcium and phosphorus normally
  have a relationship to each other that the body
  keeps fairly constant.

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Ovary

• The ovaries are the female reproductive organs,
  or gonads.
• They are paired, almond-shaped bodies situated
  on either side of the uterus.
• The ovarian follicles produce the ova, or eggs,
  and also secrete a group of hormones called
  Estrogens, which are necessary for the
  development of the reproductive organs and of
  such secondary sexual characteristics as the
  distribution of fat, widening of the pelvis,
  breast growth, and pubic and auxiliary hair.

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TESTIS
OVARY
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Testes

• The male gonads, the testes, are paired,
  ellipsoid bodies suspended in the scrotum.
• The Leydig cells of the testes produce one or
  more male hormones, called Androgens.
• The most important of these is Testosterone,
  which stimulates the development of secondary sex
  characteristics, influences the growth of the
  prostate and seminal vesicles, and promotes
  secretory activity of these structures. T
• he testes also contain cells that produce sperm.

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Pancreas

• The bulk of the pancreas consists of exocrine
  tissue that releases digestive juices into the
  duodenum.
• Distributed throughout this tissue are clusters
  of endocrine cells called the Islets of
  Langerhans, which secrete Insulin and another
  hormone, Glucagon.
• Insulin affects carbohydrate, protein, and fat
  metabolism, increasing the rate of sugar
  utilization and promoting the formation of
  protein and storage of fat. Glucagon temporarily
  raises blood-sugar levels, apparently by
  releasing glucose from the liver.

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PANCREAS
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Production of insulin
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