The Endocrine System: A Messenger

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Whenever we experience changes in our body, mood swings or other things which are quite hard to explain, it's impossible not to hear this one familiar word: HORMONES. Does it explain everything? Does it make us understand why these things happen? We must admit, it actually gives us more questions in mind. To learn more about HORMONES, we need to know more about Endocrinology. 

THE ENDOCRINE SYSTEM

The word endocrine comes from two Greeks words: endo which means "within" and krino which means "to separate". This means that chemical signals are produced within and secreted from the endocrine glands. The endocrine system is responsible for the production and secretion of hormones which would release chemical signals into the circulatory system to carry these signals to the different parts of the body, affecting one or more organs.With this, theSome of the main functions of the endocrine system include:

• Regulation of water balance. The endocrine system makes this possible by controlling the solute concentration of the blood.
• Regulation of uterine contractions during delivery of a newborn and stimulation of milk release from the breasts of a lactating mother.
• Regulation of growth of many tissues, metabolism and tissue maturation. The endocrine system regulates the growth of different tissues such as bone and muscle tissues. The endocrine system also influences the maturation of tissues resulting in the development of adult features and behavior.
• Regulation of Na+, K+ and Ca+ concentrations in the blood. With this said, the endocrine system helps in ion regulation.
• Regulation of heart rate, blood pressure and blood glucose. 
• Immune system regulation. The production and functions of the immune cells are also controlled by the endocrine system.
• Control of reproductive functions. The endocrine system also controls the reproductive functions of both males and females.

HORMONES

The word hormone is derived from the Greek word hormon, meaning "set into motion", and hormones "set responses by cells into motion". Hormones are the fluids produced by endocrine glands These are the "messengers" which will travel in the circulatory system to send signals to the different parts of the body. Hormones may be classified by chemical structure into three classes: (1) steroid hormones, (2) amino acid derivatives, and (3) peptide hormones.

ENDOCRINE GLANDS

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Glands are responsible for producing and storing fluids which the body needs; but the endocrine glands are not like other glands in the body, since they have no tubes where their secretions would flow through, and thus they are called ductless glands.  Without these tubes, endocrine glands will directly secrete the fluids(hormones) to the circulatory system, to be able to send signals to the different parts of the body.

The major endocrine glands found in the body are the pituitary gland, hypothalamus, thyroid glands, parathyroids, adrenals, pineal bodies, and the ovaries and testes.

References:

• http://www.emedicinehealth.com/anatomy_of_the_endocrine_system/article_em.htm
• http://biology.clc.uc.edu/courses/bio105/endocrin.htm
• http://www.takdangaralin.com/science/life-science/endocrine-system/endocrine-system-the-endocrine-glands/
• Seeley, Stephens et. al, Essentials of Anatomy and Physiology, sixth edition, 2007