Glands of the endocrine system secrete hormones into the area around the cells and are eventually picked up by the blood stream for transport to the receptor proteins of targeted cells. Endocrine glands all have two things in common; they are ductless glands and they produce hormones.
A hormone is a substance, molecule actually, that regulates or coordinates some other body function by acting on some particular organ.
They are chemical messengers; hormone literally means to "urge on" and there are 50 or more hormones in the human body.
Hormones fall into four categories according to their chemical structure.
There are steroids, amines, polypeptides and glycoproteins but more on those later. By the way, know how to make a hormone? Never mind, stupid joke!
For comparison, exocrine (exo = out; crine = to secrete) glands have ducts that carry their output directly into the hollow area (lumen) of the receptive organ.
Unless you just arrived from some far away galaxy, you will be familiar with many of the endocrine system glands. Going from head to groin, the Hypothalamus has an endocrine function as does the Pineal, Pituitary, Thyroid, Parathyroid, Thymus, Adrenals, Pancreas, Ovaries and Testes.
The stomach and kidneys, while not considered endocrine glands, do have endocrine type secretions.
For the Adrenals, Ovaries and Testes; it's two per customer, all we get is one each of all the others. Well, not quite; we get four parathyroid glands.
Each of the endocrine glands produces specific hormones for a specific purpose and only the targeted cell with its unique receptor can respond.
It should be noted that it is possible for some hormones to interact with each other to produce some new effect that neither could produce acting alone.
The receptors are incredibly important. Recall that endocrine hormones go into the blood stream which means they are carried to all parts of the body; they go with the flow as it were.
If it weren't for the receptor cells, hormones would be causing all kinds of havoc, regulating or inhibiting functions that are none of their business. Remember receptor cells when we get to the pancreas and diabetes.
Let’s take a look at each of the endocrine glands and see what makes them tick, what makes them not tick and what we can do to help them along.
For its size, the endocrine system's pituitary gland packs a punch. This little pea sized gland that sits in its protective bony cavity at the base of the brain was once thought to be the master of all the other endocrine system glands.
In reality, the pituitary is connected to and controlled by the hypothalamus.
The hypothalamus collects inputs from other parts of the brain, integrates them, figures out what the brain wants, and then
gives the pituitary its orders.
Between the hypothalamus and the pituitary, they produce 16 different hormones that control our primitive survival urges and reactions. What's a primitive urge? How about the following:
There may be some validity in viewing the pituitary as a master gland in the endocrine system since it does act on some other glands.
Consider that the Thyroid gland doesn't release its hormones until it receives a Thyroid-stimulating-hormone (TSH) from the pituitary. These will be covered later when we look at the Thyroid.
Consider that a Follicle-stimulating-hormone (FSH) from the pituitary as well as a luteinizing hormone (LH) work on the ovaries and testes to stimulate the release of hormones to allow maturation of the egg cells in the female and sperm and testosterone in the male. Luteinization is an intermediate step in the production of progesterones needed to maintain pregnancy.
Consider that another pituitary hormone (adenocorticotrophic hormone - ACTH) is needed by the adrenal glands to stimulate the release of adrenal cortical hormones; the "stress" hormones linked to the flight or fight response.</p>
Other pituitary hormones stimulate milk production in the breasts, control skin pigmentation, and regulate body growth and metabolic processes. Maybe the Pituitary is the Master endocrine system gland after all.
We can't leave the Pituitary without hitting on Oxytocin, Vasopressin (the Antidiuretic hormone - ADH) and Endorphins.
Oxytocin is the "love" hormone and is responsible for the feeling of sexual pleasure during and after intercourse. It fosters maternal instincts and enhances the strength of uterine contractions to speed childbirth and then stimulates milk production after delivery.
Remember "parking" with your "steady" and "making out" all night?
Thank Oxytocin for those warm fuzzy feelings. you can just see the oxytocin flowing in Romeo and Juliet.
If you ever drank too much and ended up with the mother-of-all-hangovers, you can thank ADH (vasopressin) for that experience.
The purpose of ADH is to suppress urine production which forces reabsorption by the kidneys when it's necessary to raise blood pressure.
Booze inhibits ADH production resulting in lots of trips to the restroom, causing dehydration and finally that pounding headache and hangover thirst.
Neither of these hormones is produced by the pituitary. They are made in the brain and sent to the pituitary for storage in its posterior lobe until needed.
As to the excitment and emotion that hard driving Rock'n'Roll generates, we can thank the pituitary. Endorphins are endogenous opioid polypeptide compounds produced by the pituitary gland and the hypothalamus during periods of excitement, exercise, orgasm or other enjoyable experiences.
They attach to areas of the brain responsible for pleasure (the limbic system and prefrontal cortex); so whether its rock, classical or easy listening; music appreciation is all brain chemistry.
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Too much or too little pituitary secretion can cause:
We have already mentioned how the pituitary works on the adrenal glands so let's take a look at them.
The endocrine system has two glands that sit on top of each kidney. Being about 5 cm long, they are 5 times larger than the pituitary and have a copious blood supply from three different arteries.
Just the fact that they come in pairs and are so well fed, should indicate that they are pretty important players in our endocrine system; and they are. Lose your adrenal glands, lose your life.
Structurally the adrenals have an outer layer, the cortex, and an inner layer, the medulla. The two areas combined produce five critical hormones; three in the cortex and two in the medulla.
The adrenal cortex layer is the endocrine system factory for making classes of hormones called mineralocorticoids, glucocorticoids and androgens.
Mineralocorticoids were thusly named because they were first observed to have a role in retention of the mineral sodium.
About 96% of this group is the steroid hormone Aldosterone whose function is to control water and regulate the sodium and potassium electrolytic balance in the kidneys. In other words, it preserves homeostasis (balance).
Glucocorticoids are another class of steroid hormones of which Cortisol makes up 95% of the total secretions.
Cortisol is known as the endocrine system stress hormone but it is vital for life. It regulates or supports a variety of important cardiovascular, metabolic, immunologic and homeostatic functions.
The last of the adrenal cortex hormones are the androgens, yet another steroid hormone. These are the masculinizing hormones of the endocrine system and occur in small amounts in adult males. They regulate and maintain the masculine characteristics and are the precursor of estrogen.
In females, androgen accounts for sex drive and is converted to estrogen following menopause. Testosterone is the most prevalent and well known androgen. Let's have a big cheer for the androgens.
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Epinephrine (adrenalin) and norepinephrine (noradrenalin) are produced in the medulla; the endocrine system medulla, not the brain's medulla.
We know these two as the fight or flight hormones and are released in response to some stressful event and it needn't be a life threatening situation.
It can be a traffic jam, being late for that important job interview, missing the bosses deadline, kids screaming all day, overdue bills, the IRS audit notice, and then there's the serial killer loose in the neighborhood.
What happens when these hormones pour into our blood stream? For starters our heart rate and blood pressure increases, then the bronchioles in our lungs expand allowing us to breathe faster and deeper, our pupils dilate, we get an energy surge from fatty acids and glucose and lastly, non-essential functions are inhibited including the immune function and digestive secretions.
Obviously the immune response and digestion of food are not non-essential but it's relative. They take a backseat when our life is threatened and need to flee from the Grizzly Bear or need to deal with the serial killer.
The problem is that the world conspires to keep us in a state of chronic stress and the continual presence of these hormones combined with cortisol degrades our immune system and can cause cardiovascular scarring and plaque buildup.
Cortisol, one of the adrenal cortex hormones mentioned above is particularly troublesome if it is not cleared from the blood. It depresses the immune system, promotes protein breakdown, releases fatty acids from triglycerides, increases blood pressure, and glucose formation. All designed to equip us to handle that emergency situation.
Addison's disease is an endocrine system disorder that occurs when the adrenal glands don't produce enough cortisol. The results are low blood pressure, weight loss, low blood sugar, fatigue, muscle weakness and often, a darkening of the skin.
John Kennedy had Addison's disease. He went through some very rough times when he got stressed out and couldn't generate enough cortisol but at least he looked like he had a great tan.
Cushing's syndrome is an endocrine system disorder that's just the opposite, too much cortisol production. It results in spindly arms and legs, a "moon" face, a hump of fat deposition on the upper back that looks like a buffalo hump, flushed skin, osteoporosis and decreased immune function.
Want to learn more about the adrenal system and adrenal fatigue?
Now let's look at a real troublemaker, the pancreas.
Right, the pancreas is one of the endocrine system glands that does double duty; one role is that of a digestive organ, the other is that of an endocrine organ. It's the latter role we are concerned about here.
The output of the endocrine system pancreas is insulin and glucagon but before getting into that, we need a short overview of the pancreas.
This vital organ sits in the curve of the duodenum and the stomach and is fed by a huge supply of blood from four major arteries. Its head joins the second portion of the duodenum and the tail extends over to the spleen.
Functionally, 99% of the pancreas is made up of clusters of exocrine cells that produce digestive hormones that feed into ducts to the duodenum. Remember that an exocrine gland has ducts and feeds its output into the hollow area of the target organ.
Only 1% is devoted to producing insulin but that 1% consists of several million cells called islets of Langerhans, named after the German scientist who discovered them way back in 1869.
The graphic below shows the location of the pancreas.
Alpha and Beta cells make up almost all of the endocrine system part of the pancreas with Delta and F cells making up less than 1% combined.
It seems that a little bit more imagination could have gone into naming these cells; like glucagon cell instead of Alpha, insulin cell instead of beta, somatostatin instead of delta and polypeptide instead of F cells.
The glucagon from alpha cells, which make up about 20% of the islet cells, raise blood sugar to maintain normal levels.
Insulin from the beta cells work to lower blood sugar.
Somatostatin from the delta cells inhibit release of insulin and the polypeptide from the F cells inhibit the release of somatostatin which has the effect of increasing the release of insulin.
All the hormones released from these four cell type have one purpose in life; to control blood sugar (glucose). The consequences of failure to control blood sugar are extremely serious.
High blood sugar from too little insulin may be slow to exhibit symptoms but when it does, fatigue, confusion, a smell of acetone on the breath, coma and death can be the outcome. Treatment is the administration of insulin.
Low blood sugar from too much insulin has a faster presentation of symptoms which also include confusion, coma, shock and death. The usual treatment is oral or intravenous glucose.
While the most common affliction deriving from the pancreas is diabetes; without a doubt, the most feared is pancreatic cancer.
Due to the location of the pancreas, most pancreatic cancer isn't found until it is already late stage. In fact, it is usually found by accident while investigating some other complaint.
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You will know the disorders of high glucose levels in the blood as diabetes mellitus characterized by the three "polys" and is undoubtedly one of the most serious of endocrine system problems.
Diabetes mellitus is literally "sweet urine" and in the old days, tasting of the urine was actually a diagnostic procedure for diabetes.
Type 1 diabetes accounts for about 20% of diabetes cases and requires injections of insulin and is likely an autoimmune disease.
Type II diabetes is non-insulin-dependent and usually occurs in the adult years as opposed to Type I which is characterized as a juvenile-onset-diabetes. Type II diabetics are usually overweight or obese. It is a milder diabetes which can normally be treated by diet, exercise and insulin-stimulating drugs.
Need to boost or retard your metabolism? Go tell the Thyroid gland; the endocrine system thermostat of the body. This is the H-shaped bow tie gland just below the larynx or voice box. Its right and left legs or lobes are connected by a structure called an isthmus.
It has a rich blood supply from two major arteries and numerous thyroid veins which usually attests to the importance of an organ.
The thyroid is truly a vital gland whose hormones regulate oxygen uptake, the basal metabolic rate and maintenance of body temperature, protein synthesis, lipid and cholesterol breakdown and growth and development.
Thyroid hormones also enhance the effects of the catecholamines, ephinephrine and norephinephrine, from the adrenal medulla described previously. This enhancement could account for high blood pressure, nervousness, sweating and a fast heart rate if an excess of the hormone is produced.
Thyroid chemistry is very iodine dependent and iodine, being an element (mineral) must be ingested in food.
An enlargement of the thyroid from lack of iodine is called a goiter and is fairly common in areas where iodine is deficient in the natural diet.
Most western countries include iodine in normal table salt and goiters have become very rare in the U.S. Wouldn't it be nice if all endocrine system fixes were that easy.
Photo right: One lobe of Thyroid gland with one Parathyroid shown on top
Photo below: Woman with a goiter
Malfunctions of the thyroid can result in several conditions.
If a lack of thyroid hormone (hypothyroidism) occurs in fetal development, dwarfism, mental retardation and physical deformities can result; often referred to as cretinism.
Hypothyroidism in adult life can lead to edema (fluid accumulation under the skin), slow heart rate, low blood pressure, lethargy, low body temperature and muscle weakness. Collectively, the condition is knows as myxedema.
Hyperthyroidism, excess hormone production, causes increased heart rate and blood pressure, high body temperature, sweating, diarrhea, heat intolerance, and weight loss, even with high caloric intake.
Lastly, Graves’s disease is an autoimmune disorder in which antibodies mimic the effects of Thyroid-Stimulating-Hormone (TSH) but cannot be turned off or controlled. It causes enlargement of the thyroid and bulging eyeballs from fat deposition behind the eye.
The parathyroid glands are located behind the thyroid glands and connected to the covering of the thyroid but have no relation or interaction with thyroid function.
They are totally separate. There are four parathyroids, two on each side and they are tiny; about the size of a grain of rice or small pea.
Their function is to regulate calcium and phosphorus in the blood; a most valuable service performed by our endocrine system.
The principal cells of the parathyroids produce parathormone (PTH) that acts to increase bone cells which allows the reabsorption of calcium.
It also increases urinary reabsorption of calcium in the kidneys and forces excretion of phosphorus by the kidneys. It causes the kidneys to form calcitrol, a hormone made from vitamin D, that increases the absorption of calcium from the GI system.
Increased production of PTH (hyperparathyroidism) usually occurs as a result of a tumor in one of the parathyroid glands and causes calcium to be reabsorbed from the kidneys, bones and stomach into the blood.
The medical community uses "stones, bones, groans and moans" to refer to the classic set of four symptoms.
They refer to kidney stones, osteoporosis, groans of pain from duodenal ulcers and moans from a psychosis. Removal of the parathyroid tumor can provide immediate and dramatic return to normal function. You really don't want one of the rocks pictured on the right and left; they will give new meaning to "moans and groans".
Photo right: Eight mm kidney stone
Photo above: Staghorn calculus (kidney stone) in x-ray
The opposite condition, hypoparathyroidism, leads to low serum calcium and over-excited nerves and muscles exhibiting twitching and jerking. It the extreme, it can lead to convulsions and death.
The condition is usually caused by a surgeon who inadvertently removes one or more parathyroid glands. They are the smallest of the endocrine system glands and very hard for the surgeon to find. They could easily be mistaken for a little blob of fat.
It sounds strange but removed parathyroid glands can be chopped up and implanted into muscle tissue in other areas of the body where they may survive and start producing PTH again. If the procedure fails, the patient will need lifelong injections of calcium and vitamin D; very hard to manage.
The last endocrine system gland is the pineal, located in the center of the brain between the hemispheres tucked away in a small groove. It has the shape of a small pine cone, thus the name, and is about pea sized in the early years of life.
Its function is the production of melatonin, a derivative of the amino acid tryptophan. The true function of melatonin in humans isn't clear but what is known is that production of melatonin is stimulated by darkness and inhibited by daylight.
The implication would be that the pineal gland has a regulatory role in the circadian rhythm of sleep and in fact melatonin is prescribed for circadian sleep disorders.
In children, the pineal is large, reduces in puberty and typically calcifies in the adult years. It appears that as adults, we can do without endocrine systems pineal gland
Disorders of the pineal are very rare possibly due to its deceasing size and function as we age.
All the preceeding information about the endocrine system glands is well and good but what do we do with it?
The main thing we need to do is understand the importance of good endocrine system health; after all, hormones are the regulators of our entire body. They affect every function.
The basics are that every endocrine system gland is an organ and as such they are susceptible to toxins, they need nutrients which all arrive through a copious blood supply, and they need to be exercised but not abused.
The pancreas, for example, can wear out through constant demands for insulin as a result of excessive glucose loading of our blood.
The first priority is to protect the blood supply that feeds every endocrine system gland. One of the most important things for good vascular health is to avoid or manage stress.
The second priority would be weight control.
ORAC is the "oxygen radical absorbance capacity" which describes numerically how effcicent a food or supplement removes free radicals from the body.
Free radicals are ionized oxygen atoms that are highly reactive with our cells, resulting in mutations and the start of tumors. Many of the endocrine system disorders are linked to tumors that affect the function of the gland.
The fourth priority would be to control inflammation. Inflammation is an immune response designed to protect us from harmful pathogens such as infectious bacteria and viruses; all those things we usually refer to as "germs" and which cause infections. Without inflammation, infections or wounds would never heal.
The problem is that certain conditions can create a cascade of immune system messengers that can result in unchecked, runaway inflammation. There are at least 60 autoimmune disease conditions linked to uncontrolled inflammation and one known cause is an imbalance in our intake of the fatty acids Omega-3 and omega-6.
C-Reactive Protein (CRP) is a blood marker for inflammation and can be easily checked with lab blood test. High levels of CRP would indicate excessive levels of inflammation in the body.
The levels of inflammation can be managed with high intakes of omega-3 rich foods and supplementation with a pharmaceutical grade, molecularly distilled Omega-3.
A good endocrine system support supplement will usually contain all or most of the following ingredients:
Wild Yam extract, also known as Dioscorea villosa, used to control inflammation and many autoimmune conditions including asthma.
L-Glutamic Acid, an excitatory neurotransmitter, important in the metabolism of fats and sugars, helps detoxify the body of ammonia, and shows indications of being beneficial to prostate health, certain neurological disorders, epilepsy, Parkinson's and numerous others.
Glycine, a non-essential amino acid, used to treat stomach ulcers, anxiety, insomnia, hypoglycemia (low blood sugar) and gout.
L-Lysine, another amino acid, for collagen synthesis and bone health in that it helps the body absorb and store calcium. This would tend to give the parathyroids a helping hand.
L-Arginine, yet another amino acid that the body uses to make make nitric oxide which relaxes blood vessels. It also helps the body get rid of ammonia waste products, involved in protein formation, stimulates the release of growth hormone and can be converted to glucose and glycogen if needed.
Beta Sitosterol, found in pecans, saw palmetto, rice bran, and soybeans; helps reduce blood cholesterol and, in Europe, for prostate and urinary tract disorders.
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