- Author: Melanie Dell’Oro
In our articles, we often write about “influences on the hormonal system,” “chaos in the hormonal system,” or simply talk a lot about hormones. But what is actually behind all this? What exactly is this hormonal system? In the following article, we have summarized the basics for you. The hormonal system is a complex topic that could fill entire book chapters. We are therefore just scratching the surface and will take a closer look at the individual hormones later. Let’s go!
An excursion into biochemistry
Our entire body is a finely regulated system in which one gear meshes with another. Nothing happens by chance; everything has a cause and an effect. But how does our heart know that we have just met our dream person and now needs to beat faster? How does our body know that we are being hugged and can now feel completely cozy and relaxed? How do our sexual organs know that we have dressed up in the finest lace today? The unromantic answer: biochemistry. Hormones such as adrenaline, oxytocin, estrogen, and many others trigger all the reactions in our body. This starts in the first seconds of human life with cell growth, continues throughout life to maintain all bodily functions, and extends to reproduction.
The employees: Hormones
Hormones are like little messengers that tirelessly swarm around the body and deliver messages from the nervous system to the organs. For this purpose, each hormone has a very special key that fits only into the lock of very specific cells. For example, LH and FSH act in the female organism on the cells of the ovaries, while TSH acts on the thyroid cells. In this way, hormones can act very specifically. Once the hormones bind to the receptor of their target cell, they can cause a reaction in two ways. Either they activate enzymes that are already present in the cell, which then leads to a response from the cell itself (e.g., muscle contraction). And/or they promote the production of new enzymes in the cell, for example growth factors that lead to cell growth.
Good to know: Enzymes are protein molecules that speed up chemical reactions in the body.
The department heads: Thyroid, adrenal glands, and others
Hormones that act on target cells are called effector hormones. They are produced and released by effector glands. These are endocrine glands, meaning glands that release their metabolic products into the bloodstream. Through the bloodstream, the hormones can be distributed throughout the entire organ system. The effector glands include:
- Thyroid and parathyroid glands: Thyroid hormones as well as calcitonin and parathyroid hormone are produced here. Thyroid hormones act on the entire metabolism and influence growth and performance. Calcitonin and parathyroid hormone are the central hormones of calcium metabolism, and are therefore important for bones and teeth.
- Adrenal glands: Various hormones are produced in the adrenal cortex and medulla, which have their effector cells in the kidney (e.g., aldosterone) and in smooth muscle (e.g., adrenaline, noradrenaline). Cortisol (“the stress hormone”), which we have also mentioned many times before and which acts in many areas of metabolism, is also produced in the adrenal cortex. You can find detailed information in our article on stress and the adrenal glands.
Good to know: Smooth muscle is the muscle that we cannot actively contract, such as the heart muscle, blood vessel walls, or the muscles in the digestive tract.
- Pancreas: The pancreas produces the hormones that are important for our sugar metabolism: glucagon and insulin.
- Ovaries: Depending on the phase of the cycle, the female sex hormones progesterone and estrogen are produced in the ovaries. Small amounts of testosterone are also produced here.
- Testes: The male sex hormone testosterone is produced in the testes, which regulates the production of sperm.
Management and executive secretariat: Hypothalamus and pituitary gland
There is still an authority in the human body that has the final say. In this case, it is the so-called higher-level hormone glands located in the brain. Without their signal, the hormone cascade is never set in motion in the first place. The hypothalamus plays the key role here. It sends the signals that start all hormonal processes. The so-called releasing hormones (English: release = release) actively stimulate the pituitary gland, where the appropriate hormones for the effector organs are then released. For example, gonadotropin-releasing hormone causes the anterior pituitary gland to release the gonadotropins LH and FSH, which in turn cause the ovaries to produce sex hormones. The hypothalamus also releases hormones that act on the kidney, as well as oxytocin, which is known as the cuddling hormone.
For the sake of completeness, we do not want to leave out the pineal gland. Its hormone is melatonin, which is all about the day-night rhythm.
A sensitive system
Where activity is increased, the brakes must also be applied at times. This is true for our hormonal system just as it is for our entire body (read all about stress and its effects here). For this reason, every hormone released into the bloodstream and every enzyme produced in the target cells triggers a feedback mechanism. Effector hormones circulating in the bloodstream signal to the pituitary gland and the hypothalamus that the activation of the glands has worked and that they can now be dialed back. The hypothalamus then releases the release-inhibiting hormones (English: inhibit = inhibit). A certain concentration of the produced enzymes and metabolic byproducts has the same effect on the effector glands.
Out of balance
Various circumstances in life and pathological changes in the body can cause this sensitive system to become disrupted. This has a wide range of consequences. If you follow our blog closely, you will know that in the context of the female cycle, we repeatedly touch upon the birth control pill and its influences on the hormonal system. Stress is also a major factor in hormonal imbalance.
Of course, there are still many other illnesses and factors that have serious effects.