Types Of Hormones And Their Functions In The Human Body
Hormones are molecules of diverse nature that are produced in the secretory or endocrine glands Working together with the nervous system, they are responsible for us acting, feeling and thinking the way we do.
The different types of hormones are released in the blood vessels or in the interstitial space where they circulate alone (bioavailable), or are associated with certain proteins until they reach the target organs or tissues where they act. Hormones are part of the group of chemical messengers, which also includes neurotransmitters such as dopamine, serotonin or GABA.
The functions of hormones are varied, but whether a hormone comes from a plant, an invertebrate or vertebrate animal, it is responsible for regulating several important functions. However… Why are hormones so important?
One of the functions they play is to ensure correct growth. In humans, the pituitary gland is responsible for secreting growth hormones during childhood and adolescence. In invertebrate animals, such as insects, growth hormone is involved in the molting or renewal of the integuments (body coverings), that is, the shedding of the outer layer. In the case of plants, there are several hormones that are responsible for the proper growth of roots, leaves and flowers.
In addition to this very important function, hormone functions include :
Coordinating with the brain
Another fact that we must take into account is that some biological processes are less costly if, instead of creating a constant torrent of electrical firing by neurons to activate certain regions of the organism, simply we emit types of hormones and let them be carried away by the blood until you reach your destination. In this way we achieve an effect that lasts several minutes while our nervous system can take care of other things.
In that sense, hormones work by coordinating with the brain to activate and deactivate parts of the body and thus ensure that we adapt to circumstances in real time. Of course, the effects of the release of these hormones take a little longer to be noticed than those caused by neurons.
Classification of hormones: what types of hormones are there
However, There are different classifications of hormones
What are these classifications and according to what criteria are they established? We explain it to you below.
1. By proximity of its synthesis site to its action site
Depending on whether they have their effect on the same cells that synthesized it or on adjacent cells, hormones can be:
2. According to its chemical composition
According to their chemical composition, there are four types of hormones
3. According to its nature
Depending on this class of substances produced by the body through its nature, there are the following types of hormones:
4. According to its solubility in the aqueous medium
There are two types of hormones depending on their solubility in the aqueous medium:
Hydrophilic Hormones (water-soluble) : These hormones are soluble in the aqueous medium. Since the target tissue has a membrane with lipid characteristics, hydrophilic hormones cannot cross the membrane. Thus, this type of hormones bind to receptors found outside the target tissue. For example: insulin, adrenaline or glucagon.
Lipophilic Hormones (lipophilic) : These hormones are not soluble in water, but they are soluble in lipids. Unlike the previous ones, these can cross the membrane. Therefore, the receptors for this type of hormones can bind to intracellular receptors to carry out their action. Examples: thyroid hormone or steroid hormones.
Hormones are produced in endocrine glands throughout the body. In many ways, our nervous system needs the collaboration of other parts of the body to ensure that the processes carried out within the body are coordinated and a certain balance is maintained.
To achieve this level of coordination, our brain regulates the release of several types of hormones responsible for carrying out different functions. Furthermore, this class of substances varies depending on the type of gland that secretes them, and its location.
The main endocrine glands are:
The pituitary gland or pituitary gland : It is considered the most important gland of the endocrine system, because it produces hormones that regulate the functioning of other endocrine glands. It can be influenced by factors such as emotions and seasonal changes.
The hypothalamus: This endocrine gland controls the functioning of the pituitary gland, secreting chemical substances that can stimulate or inhibit hormonal secretions from the pituitary.
He thymus : Secretes a hormone called thymosin, responsible for stimulating the growth of immune cells
The Pineal gland : Produces melatonin, a hormone that plays an important role in adjusting sleep and wake cycles.
The testicles : These produce hormones called estrogens, the most important of which is testosterone, which tells men that the time has come to begin the bodily changes associated with puberty, for example, the change in voice and the growth of beard and hair. pubic hair.
The ovaries : They secrete estrogen and progesterone. Estrogen tells girls when to begin the bodily changes associated with puberty.
The thyroid : In this endocrine gland, thyroxine and triiodothyronine are produced, hormones that control the speed at which cells burn fuel from food to produce energy.
The Kidney glands : These glands have two parts. One produces hormones called corticosteroids, which are related to the balance between mineral salts and water, the response to stress, metabolism, the immune system, and sexual development and function. The other part produces catecholamines, for example, adrenaline.
The parathyroid : From here, parathyroid is released, a hormone related to calcium concentration in the blood.
He pancreas : Secretes insulin and glucagon, which helps maintain a stable concentration of glucose in the blood and provides the body with enough fuel to produce the energy it needs.
Kosfeld M et al. (2005). Oxytocin increases trust in humans. Nature 435:673-676.
