Hormones
 

Hormones are chemical messengers that are secreted directly into the blood, which carries them to organs and tissues of the body to exert their functions. There are many types of hormones that act on different aspects of bodily functions and processes. Some of these include:
• Development and growth
• Metabolism of food items
• Sexual function and reproductive growth and health
• Cognitive function and mood
• Maintenance of body temperature and thirst

[B]Where are they secreted from?[/B]
Hormones are secreted from the endocrine glands in the body. The glands are ductless, so hormones are secreted directly into the blood stream rather than by way of ducts. Some of the major endocrine glands in the body include:
• Pituitary gland
• Pineal gland
• Thymus
• Thyroid
• Adrenal glands
• Pancreas
• Testes
• Ovaries
These organs secrete hormone in microscopic amounts and it takes only very small amounts to bring about major changes in the body. Even a very slight excess of hormone secretion can lead to disease states, as can the slightest deficiency in a hormone.

[B]Hormones and Diseases[/B]
Hormone disorders are diagnosed in the laboratory as well as by clinical appearance and features. Laboratory tests can be used to test bodily fluids such as the blood, urine or saliva for hormone abnormalities.
In the case of hormone deficiency, a synthetic hormone replacement therapy may be used and in cases of excess hormone production, medications may be used to curb the effects of the hormone. For example, a person with an underactive thyroid gland or hypothyroidism may be treated with synthetic thyroxine which can be taken in the form of a pill, while a person with an overactive thyroid may be administered a drug such as propranolol to counteract the effects of the excess thyroid hormone.

[I]A useful article.[/I]

List of important hormones and their functions.
 

[B]1. Hormones of Thyroid[/B]
Thyroid gland basically releases two hormones Triiodothyronine (T3) and Thyroxine (T4), which helps in controlling the metabolism of our body. Further these hormones regulates weight, determines energy levels, internal body temperature, skin, hair etc.

[B]2. Insulin[/B]
This hormone is released by pancreas, a leaf like gland located in the abdominal cavity behind the stomach. It allows the body to use glucose or sugar from carbohydrates in the food for energy or to store glucose for future use. It helps in keeping blood sugar level from getting too high i.e. hyperglycemia or too low i.e. hypoglycemia.

[B]3. Estrogen[/B]
It is a female sex hormone released by the ovaries. It is responsible for the reproduction, menstruation and menopause. Excess of estrogen in the female body increases the risk of breast cancer, uterine cancer, depression, moodiness etc. If estrogen level is less in female body leads to acne, skin lesions, thinning skin, hair loss etc.

[B]4. Progesterone[/B]
Progesterone hormone is produced in the ovaries, the placenta when a woman gets pregnant and the adrenal glands. It stimulates and regulates various functions. It plays an important role in maintaining pregnancy. It helps body to prepare for conception, pregnancy and regulates the monthly cycle. When pregnancy doesn’t occur, progesterone levels drop and menstrual cycle occurs. It also plays a role in the sexual desire.

[B]5. Prolactin[/B]
This hormone is released by the pituitary gland after a child birth for lactation, which enables female to breast feed. Levels of prolactin hormone rise during pregnancy i.e. it also plays an important role in fertility by inhibiting follicle stimulating hormone (FSH) and gonadotropin-releasing hormone (GnRH).

[B]6. Testosterone[/B]
It is a male sex hormone. It is an anabolic steroid by nature which helps in building body muscles. In males it plays an important role in the development of male reproductive tissues; testes and prostrate. It also promotes secondary sexual characteristics like increasing the mass of muscles and bones, growth of body hair etc. If testosterone is secreted insufficient in men then it may lead to abnormalities including frailty and bone loss.

[B]7. Serotonin[/B]
It is a mood-boosting effect hormone or also known as nature’s feel-good chemical. It is associated with learning and memory, regulating sleep, digestion, regulates mood, some muscular functions etc. Due to the imbalance of serotonin in the body, brain does not produce enough of the hormone to regulate mood or stress level. Low level of serotonin causes depression, migraine, weight gain, insomnia, craving of carbohydrate etc. Excess level of serotonin in the body causes agitation, stage of confusion, sedation etc.

[B]8. Cortisol[/B]
This hormone is produced by the adrenal gland. It helps you stay healthy and energetic. Its main role is to control physical and psychological stress. In danger condition it increases heart rate, blood pressure, respiration etc. At stressful times body secretes cortisol to cope up with the situation. High level of cortisol consistently causes ulcer, high blood pressure, anxiety, high levels of cholesterol etc. Similarly, low level of cortisol in the body causes alcoholism, condition responsible for a chronic fatigue syndrome etc.

[B]9. Adrenaline[/B]
Adrenaline hormone is secreted in the medulla in the adrenal gland as well as some of the central nervous system’s neurons. It is also known as emergency hormone because it initiates the quick reaction which makes the individual to think and respond quickly to the stress. It increases the metabolic rate, dilation of blood vessels going to the heart and the brain. During stressful situation, adrenaline quickly releases in to the blood, send impulses to the organs to create a specific response.

[B]10. Growth Hormone[/B]
It is also known as somatotropin hormone. It is basically a protein hormone having 190 amino acids which is synthesised and secreted by the cells called somatotrophs in the anterior pituitary. It stimulates growth, cell reproduction cell regeneration and in boosting metabolism. It is important in human development.