Ductless glands that empty their secretions directly into the blood stream; these secretions contain specific hormones that influence growth, reproduction, emotion.
Glands that secrete their products (hormones) into the blood, which then carries them to their specific target organs. For example, adrenalin, produced in the adrenal glands, is carried to the heart (and other muscles) when needed during periods of stress. The endocrine glands are: the pituitary, thyroids, adrenals, pancreas, ovaries (in females) and testes (in males). Endocrine glands are found in some invertebrates as well as in vertebrates.
Glands that secrete hormones into the blood stream or lymphatic system.
A gland without a duct which produces hormones which are introduced directly into the bloodstream, e.g. the pituitary gland, thyroid gland, the adrenal gland and the gonads.
Specialized cells and tissues that release hormones into the bloodstream. These hormones have as their targets tissues some distance away from the tissue of origin.
Any ductless gland (e.g., pituitary gland) that releases its secretion—a hormone—directly into the bloodstream, through which it moves to specific target organs to produce an effect.
A gland that manufactures one or more ‘hormones and secretes them directly into the bloodstream (and not through a duct to the exterior). Endocrine glands include the pituitary, thyroid, parathyroid, and adrenal glands, the ovary and testis, the placenta, and part of the pancreas.
Organs whose function is to secrete into the blood or lymph, substances known as hormones. These play an important part in general changes to the activities of other organs at a distance. Various diseases arise as the result of defects or excess in the internal secretions of the different glands.
A ductless gland that secretes one or more hormones directly into capillaries. The endocrine glands include the pituitary gland (which produces thyroid-stimulating hormone, adrenocorticotropic hormone, luteinizing hormone, follicle-stimulating hormone, growth hormone, endorphins, and prolactin); the hypothalamus (which produces thyrotropin-releasing hormone, growth hormone-releasing hormone, somatostatin, dopamine, gonadotropic hormone-releasing hormone, antidiuretic hormone, and oxytocin); the thyroid gland; the parathyroid glands; the adrenal glands; the islets of the pancreas; and the gonads (testes and ovaries). During pregnancy, the placenta is an endocrine gland that secretes estrogen and progesterone to maintain pregnancy.
An organ that releases hormones into the bloodstream or into the fluid around cells.
Glands such as the thyroid and pituitary gland that release hormonal secretions directly into the bloodstream.
One of a group of ductless glands that release hormones directly into the bloodstream.
An endocrine gland, devoid of ducts, such as the pituitary, thyroid, or adrenal gland, which releases its secretions directly into the bloodstream or lymphatic system.
An endocrine gland is a specialized type of organic structure, an alchemist transforming intangible signals into potent biochemical couriers—hormones—that are liberated directly into the sanguine highway, bypassing any form of ductwork. Such glandular masterpieces of biology encompass the thyroid, the pituitary, the ovaries, the testes, and the adrenal glands. These secretory sentinels come together in a harmonious concert, forming the grand orchestra of internal communication, the endocrine system.
Ductless glands that secrete hormones into the blood and that have a particular effect on other organs. They are also known as ductless glands and include the following. The adrenal (sometimes called the suprarenal) is situated above the kidney. The cortex (outer layer) of the gland produces many steroids with cortisone like activity that affects carbohydrate metabolism, increases protein
breakdown, produces an anti-inflammatory reaction, acts on the kidney in controlling the elimination of salt and water, and affects the sex glands. The medulla (inner part) of the gland produces epinephrine and norepinephrine, which raise the blood pressure, stimulate metabolism, and mobilize glycogen as glucose. The pancreas, situated within the abdomen, produces insulin and glucagon, which controls carbohydrate metabolism, and produces digestive enzymes (an exocrine function). The parathyroid gland, situated in the neck, controls calcium in the body. The pineal gland, situated in the brain, produces melatonin. This gland calcifies with age and serves as a useful radiologic landmark. The pituitary gland, situated in the brain, has three parts; between them they liberate a large number of hormones including a growth hormone, a thyroid-controlling hormone, an adrenocorticotrophic hormone, gonadotropin, a milk-stimulating hormone (prolactin), an oxytocic hormone, which contracts the womb, a vasopressor hormone, which raises blood pressure,
and an antidiuretic hormone, which reduces the output of urine. From the thymus, situated in the
chest, no specific hormone has been isolated, though there does appear to be a connection between this gland and myasthenia gravis. The thyroid gland, situated in the neck, produces thyroxine, which controls growth and development. This gland influences other glands and has been described as the master gland.