The human body is a complex entity that requires power (nutrients and oxygen) and a round the clock production schedule to make sure that the nutrients that we take in are converted to all the chemical components required to keep us functioning healthily. One of the most important production lines is created by the endocrine system ensuring that the right messages are sent to the various organs to keep them running at full capacity. Recently I shared the main components required to keep those messages circulating Cholesterol Part Three
The endocrine system and hormones Part One
One of the miracles of the human body is the way it ensures the survival of the species over millions of years. For example, baby girls are born with over 400,000 eggs in their ovaries and over the next 10 to 12 years their endocrine system will mature and various physical, mental and emotional changes will take place to ensure that as a woman, she will be able to give birth to the next generation.
Hormones are vital not just to an efficient reproductive system but to our health in general.. Their protection is essential and maintaining adequate levels throughout our lifetime can be a challenge. And it is not helped by pronouncements by ‘experts’ on the food we eat and the medication that they prescribe to reduce one of the key elements of our hormone production which is cholesterol.
The Endocrine system not only produces the sex hormones but also the other hormones necessary for the healthy growth and development of every cell, organ and function within our bodies. Usually responsible for the slower processes such as cell growth, the endocrine glands and hormones will also work with other systems such as the nervous system to ensure the smooth running of processes like breathing and movement.
A gland is a group of cells that produce and secretes chemicals from materials that it has selected from the blood stream. It processes these raw materials and either secretes the end product in specific areas, such as the salivary glands or sweat glands in the case of the exocrine glands, or directly back into the bloodstream from the endocrine system.
The main glands that make up the endocrine system are the hypothalamus, pituitary (master gland), thyroid, parathyroids, adrenals, pineal, ovaries and testes.
The pancreas is also part of the endocrine system but is associated more with the digestive system and digestive enzymes.
A healthy reproductive system for men or women begins in the brain.
The other name of the hypothalamus is actually the word homeostasis, which means balance, which is very appropriate. It is located in the middle of the base of the brain and is connected to the pituitary lobes, which form the most important gland in the body and is often referred to as the Master Gland.
The hypothalamus regulates body temperature, blood sugar, water balance, fat metabolism, appetite, body weight, sensory input like taste and smell and sight, sleep, sexual behaviour, emotions, hormone productions, menstrual cycle regulation and the automatic nervous system that controls automatic functions such as breathing and the heart muscle.
The Pituitary gland
The pituitary gland has an anterior and posterior lobe. The anterior lobe regulates the activity of the thyroid, adrenals and the reproductive glands producing a number of hormones.
- Growth hormone stimulates the growth of bone and body tissues and plays a part in the metabolism of nutrients and minerals.
- Prolactin, which activates milk production in mothers who are breast-feeding.
- Thyrotropin which stimulates the thyroid to produce hormones.
- Corticotrophin which stimulates the adrenal glands to produce its hormones.
- Gonadotrophs are cells that secret the two hormones that stimulate hormone production in the ovaries and testes. These are called luteinising hormone (LH) and follicle stimulating hormone (FSH) and whilst not essential to life are essential to reproduction.
The pituitary gland also secretes endorphins, which act as natural pain relief within the nervous system. It is also the gland that releases hormones that signal the ovaries and testes to make the sex hormones and controls the ovulation and menstrual cycle.
The posterior lobe of the pituitary has two main functions one of which is the release of a hormone to control water balance through its effect on the kidneys and urine output. The second is the release of oxytocin the trigger for contractions of the womb during labour.
The thyroid is located in the front of the lower neck and is shaped like a bow tie. It produces the hormones thyroxine and triiodothyronine which are responsible for the speed with which cells burn fuel to provide energy. This is our metabolism or the speed at which we operate. The production and release of these two hormones is controlled by Thyrotropin, which is secreted by the pituitary gland.
The thyroid needs iodine and selenium to produce an enzyme, which converts the amino acid tyrosine into thyroxine. If thyroxine is at a less than optimum level there will be weight gain, fatigue, intestinal problems and thickening skin.
Attached to the thyroid are four tiny glands that release parathyroid hormone that is responsible with calcitonin also produced in the thyroid for calcium balance between blood and bones. If this is not working then too much calcium is leached from the bones leaving them vulnerable to osteoporosis
The Adrenal glands
The Adrenal glands are actually situated on top of each kidney and comprise two parts. The first is the cortex, which produces hormones called corticosteroids, which determine male characteristics, sex drive, stress response, metabolism and the excretion of sodium and potassium from the kidneys.
The second part of the gland is the medulla, which produces catecholamines such as epinephrine (adrenaline) to increase blood pressure and heart rate in times of danger or stress.
If your stress levels remain high for long periods of time there will be an effect on the rest of your body. The body slows down digestion, maintenance and repair so that it is ready to run at any moment. It definitely speeds up the ageing process because like anything that is not maintained it slowly deteriorates. It will have a very big impact on all the rest of the hormones in the body including your sex drive, which is why stress plays a very important role in problems such as impotence and infertility.
The Pineal gland
This gland is located in the middle of the brain and secretes melatonin, the hormone that regulates sleep cycles. Being tired all the time will certainly not help maintain a healthy hormone balance.
Ovaries and Testes
These two glands are known as the gonads and are the main source for the sexual hormones. In the female these are the ovaries.. They secrete oestrogen and progesterone as needed, particularly in girls who have reached puberty and are developing breasts and layers of fat around the hips and thighs that would be used primarily to nourish a foetus during pregnancy. Both hormones regulate the menstrual cycle, which is why an imbalance can cause irregular periods or infertility.
Oestrogen hormones include estradiol, estrone and estriol and as well as their role in the developing female they also have important effects on organs outside of the reproductive system. In fact they have an effect on over 300 different tissues throughout a woman’s body including in the central nervous system, liver and the urinary tract. One of their functions is in maintaining bone mass as a woman ages, particularly after the menopause. They also have a positive effect on blood fat and therefore help prevent atherosclerosis and possible heart disease. As we age our skin tends to thicken and oestrogen hormones help preserve the elasticity of the skin as well as promote a sense of general wellbeing.
Progesterone also has duties outside of its reproductive remit and that is its influence on body temperature. This is why taking your temperature every morning during the month can help you pinpoint when you might be ovulating.
As these hormones diminish so does the activity within the ovaries. They become smaller and lighter and the blood vessels that supply them atrophy. The follicles decrease in number and fewer and fewer eggs are produced sometimes skipping several months at a time resulting in irregular periods. Eventually egg production ceases completely, as does menstruation, and after twelve months you are usually unlikely to conceive but it is recommended that you still practice birth control for up to two years after completely finishing your periods.
Thyroid image http://www.medicinenet.com
Next week a closer look at hormones and how the food we eat has a direct impact on their effectiveness.
©Just Food for Health 1998 – 2020
I am a qualified nutritional therapist with twenty-two years experience working with clients in Ireland and the UK as well as being a health consultant on radio in Spain. Although I write a lot of fiction, I actually wrote my first two books on health, the first one, Size Matters, a weight loss programme 20 years ago, based on my own weight loss of 154lbs. My first clinic was in Ireland, the Cronin Diet Advisory Centre and my second book, Just Food for Health was written as my client’s workbook. Since then I have written a men’s health manual, and anti-aging programme, articles for magazines and posts here on Smorgasbord.
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