 | Term | Definition |
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endocrine system |
The second major controlling system of the body that acts with the nervous system. It employs more slowly acting chemical messengers into the blood to be transported throughout the body. |
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Hormones |
chemical "messengers" of the endocrine system that are released into the blood |
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target organs |
Organs that respond to a particular hormone |
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Pituitary gland |
aka hypophysis, is located in the concavity of the sella turcica of the sphenoid bone. consists of two functional lobes (the anterior and posterior) |
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infundibulum |
A stalk that attaches the pituitary gland to the hypothalamus. |
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tropic hormone |
Stimulates a target organ, an endocrine gland, to secrete its hormone. Which in turn exert their effects on other body organs |
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FSH and LH |
Secreted by the aneterior pituitary. They regulate gamete production and hormonal activity of the gonads |
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ACTH |
Secreted by the anterior pituitary. It regulates the endocrine activity of the cortex portion of the adrenal gland. |
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TSH or thyrotropin |
Secreted by the anterior pituitary. It influences the growth and activity of the thyroid gland |
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GH |
Secreted by the anterior pituitary. It is a general metabolic hormone that plays an important role in determining body size. It affects many tissues of the body; however its major effects are on the growth of muscle and the long bones of the body. |
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acromegaly |
Hypersecretion of the GH in adults which causes an overgrowth of bones in the hands, feet, and face |
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PRL |
Secreted by the anterior pituitary. It stimulates breast development and promotes and maintains lactation after childbirth. It may stimulate testosterone production in males. |
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Hypophyseal portal system |
Serves the circulatory needs of the anterior pituitary. The release of anterior pituitary hormones is controlled by neurosecretions produced by neurons of the ventral hypothalamus. |
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posterior pituitary |
not technically an endocrine gland because it doesn't synthesize the hormones it releases, it simply acts as a storage area for two hormones. |
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Oxytocin |
Hormone that is released from the posterior pituitary in response to nerve impulses. This stimulates powerful uterine contractions during birth and coitus and also causes milk ejaculation in the lactating mother |
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ADH |
Hormone that is released from the posterior pituitary in response to nerve impulses. This causes the distal and collecting tabules of the kidneys to reabsorb more water from the urinary filtrate. |
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diabetes insipidus |
A hyposecretion of ADH which results in dehydration from excessive urine output. |
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Thyroid gland |
Two lobes joined by a central mass in the throat, inferior to the larynx, produces two major hormones. |
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Thyroid hormone (TH) |
Actually two physiologically active hormones known as T3 and T4 produced by the thyroid gland. Its primary function is to control the rate of body metabolism and cellular oxidation, therefore it affects virtually every cell in the body. |
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myxedema |
Hyposecretion of T4. This condition leads to a condition of mental and physical sluggishness. |
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calcitonin |
Produced by the thyroid gland and decreases the blood calcium levels by stimulating calcium deposit in the bones. The antagonist of the parathyroid hormone. |
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Parathyroid glands |
Glands found embedded in the posterior surface of the thyroid gland. Typically there are two small oval glands on each lobe, there may be more and some can be located in other regions of the neck. |
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Parathyroid hormone (PTH) |
Released by the parathyroid gland and is the most important regulator of calcium balance of the blood. Its release causes the release of calcium from the bone matrix and prods the kidney to reabsorb more calcium and less phosphate from the filtrate. Also activates the kidney to activate Vitamin D. |
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tetany |
Hyposecretion of PTH may lead to this, prolonged muscle spasms that can result in respiratory paralysis. |
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Adrenal glands |
Two bean-shaped gland located atop or close to the kidneys. |
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Adrenal medulla |
Part of the adrenal gland that is directly controlled by the sympathetic nervous system neurons. The cells respond to the stimulation by releasing epinephrine (80%) and norepinephrine (20%). |
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Epinephrine and norepinephrine |
Hormones released by the medullary cells of the adrenal glands in conjunction with the sympathetic nervous system to elicit the fight-or-flight response to stressors. |
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Adrenal cortex |
Part of the adrenal gland that produces three mayor groups of steroid hormones called corticosteroids. |
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Mineralocorticoids |
One of the major groups of steroid hormones produced by the adrenal cortex. It regulates water and electrolyte balance in extracellular flid, mainly by regulatind sodium reabsorption by the kidney tubules. Chiefly aldosterone. |
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Glucocorticoids |
One of the major groups of steroid hormones produced by the adrenal cortex. It enables the body to resist long-term stressors, primarily by incresing blood glucose levels. |
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Gonadocorticoids |
AKA sex hormones. One of the major groups of steroid hormones produced by the adrenal cortex. They are chiefly androgens ( male sex hormones) but some estrogen (female sex hormones) are formed. |
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Hirsutism |
hypersecretion of corticosteroids produces abnormal hairiness and masculinization. |
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Pancreas |
located partially behind the stomach in the abdomen, and it functions as both an endocrine and exocrine gland. It produces digestive enzymes as well as insulin and glucagon |
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Insulin |
Hormone produced by the pancreas that is released when stimulated by elevated glucose levels. This hormone decreases blood sugar levels by accelerating the transport of glucose into the body cells where it is oxidized for energy or converted to glycogen or fat for storage. |
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Diabetes mellitus |
The inability of blood cells to utalize glucose and the subsequent loss of glucose in urine. Caused by the hyposecretion of insulin. |
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Hypoglycemia |
Caused by hypersecretion of insulin which results in low blood sugar. |
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Glucagon |
The antagonist of insulin. Its release is stimulated by low blood glucose levels. It stimulates the liver, its primary target organ, to break down its glycogen stores to glucose and subsequently to release glucose to the blood. |
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Ovaries |
The female gonads, paired almond-sized organs located in the pelvic cavity, and produce two steroid hormone groups the estrogns and pregesterone. The endocrine and exocrine functions do not begin until the onset of puberty. |
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Estrogens |
These hormones are produced by the ovaries and are responsible for the development of the secondary sex characteristics of the female at puberty, act with progesterone to bring out the cyclic changes of the uterine lining, and help prepare the mammary glands for lactation. |
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Progesterone |
A hormone produced by the ovaries which acts with estrogen to bring about the menstral cycle. |
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Testes |
The male gonads that are oval and paired, suspended in a pouchlike sac, the scrotum, outside of the pelvic cavity. They produce the male sex cells, and testosterone, the male sex hormone. |
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Testosterone |
The male sex hormone produced by the testes which promotes the maturation of the reproductive system accessory structures, development of the male secondary sex characteristics, and is responsible for sexual drive (libido) |
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Thymus |
A bilobed gland situated in the superior thorax, posterior to the sternum and anterior to the heart and lungs. It begins to atrophy at puberty. Produces the hormones thymosin and thymopoietin, which help direct the maturation and specialization of a unique population of WBCs called T cells. |
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Pineal gland |
A small cone-shaped gland located in the roof of the third ventricle of the brain. Its major endocrine product is melatonin. Its endocrine role in the body is controversial. |
