HORMONES DEFINITION Hormones are chemical agents, transmitters among different tissues of our organism. Hormones are produced by the endocrine glands. For example, sex hormones are produced mainly by ovaries and in insignificant quantity by adrenal glands. Hormones penetrate in the blood and make a targeted organ start its function activity or stop its work. The blood contains a large quantity of various biologically active agents at the same time, however, different hormones find their targeted organs. How it is going on? There is a unique mode of action for all hormones, allowing them to know the targeted organs: hormones communicate with the specific albuminous molecules in the tissues, then penetrate into cells, and that means the process is started. It is interesting that each hormone has own specific proteinreceptor. So, this system works on the lock-and-key principle where the hormones are keys, and the receptors are locks. It is evident that if any hormones are not produced in an organism, corresponding “locks� could not be opened anymore and activity of this hormone-dependable organ will be decreased. For example, the estrogen receptors (female sex hormones) are situated practically in all tissues and organs, including the skin and the brain, thence, when sufficient quantity of estrogens is not synthesized not only genitals organs are changed, but other bodies. Ovaries are responsible for normal function of the female reproductive system. However, ovaries activity is subordinated to the influence of hypophysis hormones, follicle-stimulating hormones (FSH) and luteinizing hormones. The coordinated work of hypophysis and ovaries is fulfilled on the principle of negative feedback, that means the low sex hormones level leads to making ovaries to produce more hypophyseal hormones (follicle-stimulating and luteinizing hormones level is increased). Consequently, the sufficient estrogen level is accompanied by decrease in follicle-stimulating and luteinizing hormones. As we have already known that ovarian failure leads to deficiency of estrogens, we can assume that in menopause level of these hypophyseal hormones will be significantly increased. This fact for the doctors is important since it allows to find out that menstruation stops because of lack of follicles indicating at menopause, or certain diseases. We stop our explanation at this point because we do not study diseases here. Order birth control pills online at low price. It’s much cheaper than buying at your local drugstore! What Are Hormones, and What Do They Do? Hormones are special chemical messengers in the body that are created in the endocrine glands. These messengers control most major bodily functions, from simple basic needs like hunger to complex systems like reproduction, and even the emotions and mood. Understanding the major hormone functions will help patients take control of their health.
These chemical messengers help organs, tissues, and cells communicate within the body. Hormones are chemicals produced by the body to help one part of the body communicate with another, by sending signals to certain organs, tissues, and cells. Released directly into the bloodstream by organs known as endocrine glands, hormones circulate through the body until they make contact with their target areas. The initial contact a hormone makes with a cell starts a series of important reactions carried out within that specific cell or tissue. Some of the activities of hormones include:
Prompting cell or tissue growth and development Helping with food metabolism Initiating and maintaining sexual development and reproduction Maintaining body temperature Controlling thirst Regulating mood and cognitive functioning
Hormones are extremely powerful chemicals — very small amounts can have major effects on the body. Humans, animals, and plants all produce hormones that play important roles in helping these organisms function properly. Glands and Hormones The following are examples of endocrine glands and some of the hormones they produce.
Pineal gland: Located near the back of the skull, this gland produces melatonin in response to darkness, which encourages sleep. Pancreas: This organ plays a major role in regulating blood glucose levels by producing the hormones insulin, amylin, and glucagon. Pituitary gland: Nicknamed the “master gland,” this pea-size gland is located at the base of the brain.
Hormones produced by the pituitary gland include: Growth hormone (GH), which influences development and cell production Prolactin, which stimulates milk production in breastfeeding women and has wide-ranging effects on behavior, reproduction, and the immune system Follicle-stimulating hormone (FSH), which regulates egg release in ovaries and sperm production in testes Luteinizing hormone (LH), which regulates the female menstrual cycle and works with FSH to produce sperm in men
Testes: Best known for producing testosterone (the “male hormone”), the testes actually release several different hormones, including estrogen (the “female hormone”). Testosterone is responsible for sex drive in men and women, encouraging oil production in the skin, increasing bone mass, and male characteristics such as facial hair, deepening of the voice, and the development of male genitalia during pregnancy. Ovaries: These organs produce estrogen, which helps regulate reproduction and is responsible for characteristically female traits such as breast development and increased fat stores. The ovaries also produce progesterone (the “pregnancy hormone”), which regulates both the menstrual cycle and the stages of pregnancy. Liver: Among its many functions, the liver releases insulin-like growth factor 1 (IGF-1), a hormone involved in cell growth. Scientists are studying how IGF-1 may be linked to cancer and the aging process. Hormone Imbalances Age, genetic disorders, diseases, exposure to environmental toxins, and even disruption of your body’s natural rhythm (circadian rhythm) can harm the body’s ability to produce hormones in the exact amount needed. Over- or underproduction of hormones can cause serious health problems. In these cases, doctors may prescribe hormones or other drugs to help manage these conditions and restore balance to your body’s hormonal levels. Examples of hormone-related treatments include: Hormone replacement therapy (HRT) for a woman who has either entered or finished menopause Thyroid replacement drugs such as Levoxyl or Synthroid (levothyroxine) to treat an underactive thyroid (hypothyroidism) Cytomel (liothyronine) to help shrink tissue in an overactive thyroid (hyperthyroidism) Testosterone injections for a man with a greatly diminished sex drive, or a genetic sexual disorder like Klinefelter syndrome Melatonin supplements to help initiate asleep while traveling across time zones Zemplar (paricalcitol) to manage overactive parathyroid (hyperparathyroidism) caused by kidney failure
Prostaglandins Adrenaline Aldosterone
Calcitonin Cortisol Erythropoietin Glucagon Insulin Leptin Melatonin Oxytocin Progesterone Prolactin Prostaglandins Testosterone Thyroxine Vitamin D Endocrine System
The best way to answer the question “what are hormones?” is to take a look at some of the major hormonal systems in the body. Hormones are created by glands, which are part of the endocrine system. The main hormone-producing glands are:
Hypothalamus: The hypothalamus is responsible for body temperature, hunger, moods and the release of hormones from other glands; and also controls thirst, sleep and sex drive. Parathyroid: This gland controls the amount of calcium in the body. Thymus: This gland plays a role in the function of the adaptive immune system and the maturity of the thymus, and produces T-cells. Pancreas: This gland produces the insulin that helps control blood sugar levels. Thyroid: The thyroid produces hormones associated with calorie burning and heart rate. Adrenal: Adrenal glands produce the hormones that control sex drive and cortisol, the stress hormone. Pituitary: Considered the “master control gland,” the pituitary gland controls other glands and makes the hormones that trigger growth. Pineal: Also called the thalamus, this gland produces serotonin derivatives of melatonin, which affects sleep. Ovaries: Only in women, the ovaries secrete estrogen, testosterone and progesterone, the female sex hormones. Testes: Only in men, the testes produce the male sex hormone, testosterone, and produce sperm. These glands work together to create and manage the body’s major hormones.
Types of Hormones What do hormones do, exactly? The body has many different hormones, but certain types have a bigger role to play in the body’s health and well-being. Understanding these roles is important for those looking to protect and manage their health.
For women, estrogen (or estradiol) is the main sex hormone. It causes puberty, prepares the body and uterus for pregnancy, and regulates the menstrual cycle. During menopause, estrogen level changes cause many of the uncomfortable symptoms women experience.
Progesterone is similar to estrogen but is not considered the main sex hormone. Like estrogen, it assists with the menstrual cycle and plays a role in pregnancy.
Cortisol has been called the “stress hormone� because of the way it assists the body in responding to stress. This is just one of several functions of this important hormone.
Melatonin levels change throughout the day, increasing after dark to trigger the responses that cause sleep.
Testosterone is the main sex hormone in men. It causes puberty, increases bone density, triggers facial hair growth, and causes muscle mass growth and strength.
When they are in proper balance, hormones help the body thrive, but small problems with hormones can cause serious and life-altering symptoms. If you have concerns about any of your hormones, talk to a qualified endocrinologist.
Where are they secreted from? 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. Hormones and diseases 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. ABOUT HORMONE IMBALANCE How Does My Hormone Cycle Work? Hormone Imbalance & Hormone Harmony Hormone imbalance is best understood by knowing how a normal menstrual cycle works. A menstrual cycle is the result of a hormonal dance between the pituitary gland in the brain and the ovaries. Every month the female sex hormones prepare the body to support a pregnancy, and without fertilization there is menstruation (a period).
Menstrual Cycle A menstrual cycle is determined by the number of days from the first day of one period to the first day of the next. So day one of the menstrual cycle is the first of full bleeding day of the period. A typical cycle is
approximately 24 to 35 days (average 28 days for most women). It is not abnormal for a womanšs cycle to occasionally be shorter or longer.
On Day 1 of the menstrual cycle, estrogen and progesterone levels are low. Low levels of estrogen and progesterone signal the pituitary gland to produce Follicle Stimulating Hormone (FSH). FSH begins the process of maturing a follicle (fluidfilled sac in the ovary containing an egg).
The follicle produces more estrogen to prepare the uterus for pregnancy. At ovulation, usually around Day 12 – 14, increased estrogen levels trigger a sharp rise in Luteinizing Hormone (LH) from the pituitary gland, causing release of the egg from the follicle.
The ruptured follicle (corpus luteum) now secretes progesterone and estrogen to continue to prepare the uterus for pregnancy. If the egg is not fertilized, estrogen and progesterone levels drop and, on Day 28, the menses begin.
The menstrual cycle occurs in three phases: follicular, ovulatory and luteal. The first half of the cycle is known as the follicular phase and the second half of the cycle is considered the luteal phase. Midway through the cycle between days 12 and 16 ovulation occurs, known as the ovulatory phase.
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