| Hormones | |||||
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Hormones are chemical substances which are produce by the endocrine system. Hormones can be either fat-soluble (which means they require a protein to carry them in the blood) or water soluble (which means they can freely travel through the blood).
The main hormones produced in the body are:
- Adrenaline - from the adrenal medulla
- Androgens (DHEA) - from the adrenal cortex
- Anti-diuretic hormone - from the posterior pituitary gland
- Calcitonin - from the thyroid
- Glucagon - from the pancreas
- Glucocorticoids (cortisol) - from the adrenal cortex
- Human growth hormone - from the anterior pituitary gland
- Insulin - from the pancreas
- Leutinising hormone - from the ovaries and testicles
- Mineralocorticoids (aldosterone) - from the adrenal cortex
- Noradrenaline - from the adrenal medulla
- Oestrogen - from the ovaries
- Oxytocin - from the posterior pituitary gland
- Parathyroid hormone - from the parathyroid glands
- Progesterone - from the ovaries
- Testosterone - from the testicles
- Tri-iodo-thyronine - from the thyroid
- Thyroxine (T4) - from the thyroid
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- Hormones can act on cells close to where they are released, or or on cells that distant
- Hormone levels can be measured by simple blood tests (but these levels can fluctuate at different times of the day and month depending on a number of factors)
- Hormones take a long time to exert their effect on the target cells and tissues, but the exert a long-term response
- Hormones are produced by endocrine glands or by organs that also have endocrine tissue
- Hormones control many many processes in the body, including blood fluid levels, metabolism, growth, reproduction, gestation, delivery and lactation
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Hormone secretion is controlled by a number of mechanism:
- Level of cicrulating hormone - this is the most common mechanism to control hormone secretion and happens through a negative feedback mechanism
- Direct sampling of the blood - some endocrine tissues can sample the blood that passes through them to determine if a certain hormone needs more regulation
- Nervous stimuli - nervous tissue stimulates certain hormones
- Hypothalamus - this organ controls the endocrine system by controlling activity of the pituitary gland (both the anterior and posterior)
Hormone activity in the body control a number of vital metabolic processes, such as level of blood glucose, menstruation, lactation, puberty, metabolism.
Last reviewed: 14 January 2007 || Last updated: 21 August 2007
Related Articles
references
- Marieb EM, Hoehn K. Human Anatomy & Physiology. 7th edition, 2006. Benjamin Cummings Publishing
- Osiecki, Henry. The Physician's Handbook of Clinical Nutrition. 6th edition, 2001, BioConcepts Publishing
- Rolfes SR, Pinna K, Whitney E. Understanding Normal and Clinical Nutrition. 7th Edition, 2005. Brooks Cole Publishing
- Tortora GJ, Derrickson BH. Principles of Anatomy & Physiology. 11th edition, 2005. Wiley Publishing
To learn more, go to the following web sites:
NOTE: Mega doses of any type of vitamin, mineral, amino acid or herbal supplement cannot cure illnesses and in fact can be very dangerous and produce toxic side effects and interfere with medicine you are taking. Always ensure you consult your doctor before taking any type of complementary supplements.
Disclaimer: This guide is not intended to be used for diagnostic or prescriptive purposes. For any treatment or diagnosis of illness, please see your doctor.
