Body homeostasis: what it is, and types of homeostatic processes
We are hungry and we eat, because our body warns us that we lack nutrients. We are thirsty and drink, because we are in the process of dehydration and our body needs water to function well. Our pulse and respiration are accelerated by an extremely active situation and later we calm down, because we stop being exposed to the situation that requires an energy use.
If we observe all these relationships, we can see that in all of them we are facing a process that seeks maintain a balance in our body .
This balance is necessary for the proper functioning of our body, with which we carry out different processes to achieve it. We are talking about body homeostasis , of which we are going to talk throughout this article.
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What is body homeostasis?
We understand by body homeostasis the tendency in the body to actively and constantly seek a state of equilibrium, in such a way that the cells of our body can survive by maintaining a stable internal composition.
The maintenance of this balance is fundamental, since the activation or maintenance of different bodily processes require energy, which in turn requires elements to be used as fuel. Not having them will occur a series of tissue damage that can lead to death . The same happens if we are not able to activate or stop some of the aforementioned bodily processes, necessary for our survival.
It is important to bear in mind that homeostasis acts on the basis of the existence of changes that can occur both within the body and from outside, using mechanisms of action that link both environments (for example, hunger makes us eat).
The concept of body homeostasis, developed by Bernard but baptized by Cannon , does not speak of a situation in which the body remains unchanged in a position where there are always the same parameters, but rather a dynamic balance between states that allows the values of the different components of our body to remain relatively stable , thanks to various biological mechanisms prepared for this purpose.
In this sense we must bear in mind that living beings can support certain levels of variation and imbalance and that the mechanisms that allow homeostasis can be damaged or altered throughout the life cycle , being important to take it into account in order to introduce external factors that correct possible deficits.
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In order for homeostasis to exist, the existence of three fundamental elements is necessary.
First of all it is necessary the existence of some type of elements that make sensor, a receiver that allows that the agency captures the existing levels in the parameter or element that must remain in equilibrium.
Secondly there must be some kind of control , a trigger that manages to make that at the moment when certain levels are reached, a performance is necessary.
Third and last, it is essential that there is some kind of mechanism that allows response or action once the control mechanism warns that the value of the variable or factor in question reaches the level of imbalance.
Processes to balance the organism
The process of homeostatic regulation is complex and the mechanisms that participate in it are diverse. We can highlight three of them concretely: two of them are purely biological, while the third is more related to neural activity and behavior.
The feedback or negative feedback is probably the mechanism of action of homeostasis that seems to have more logic and easier to observe and understand.
This mechanism is based on the fact that given the detection of a certain level of a specific parameter that moves away from the normal values, a response is carried out that pretends return said parameter to the previous stability .
Examples are provided in the introduction to this article. It must also be borne in mind that we are not talking about a search for balance that occurs only in situations where there is a lack, but also when there is an excess of something.
For example, in the case of variations in body water levels , thirst may arise in case the organism detects a lack of it or the need to urinate if there is an excess.
Another process necessary to maintain body homeostasis may, in fact, appear counterintuitive.It is about positive feedback, which is characterized by generating an increase in the amplification of disequilibrating stimuli, accelerating changes.
This process can be risky and even pose a danger to survival, but although it causes the organism to move further away than it would initially do from the balanced baseline, it has its utility: it may be necessary to perform this feedback or to move the basal state to a more optimal situation for survival or to achieve long-term return to initial situations.
Examples of this occur in the coagulation of the blood before an injury, which becomes increasingly rapid and facilitates the arrest of a hemorrhage.
The feedback supposes that before the arrival of a concrete signal the organism generates some type of action that allows reacting to the existence of variations.
But it is not the only way to maintain homeostasis : it is also possible to anticipate the arrival of changes and prevent them from occurring. This is the system that would be known as anteroalimentation, and on a biological level we found it more linked to the behavior and the capacity of association, as well as instinctive acts.
5 homeostatic processes that occur in our body
We have talked about body homeostasis as something general that may sound somewhat abstract to most readers (although several examples have been given).
But There are many aspects and functions of our body that must be regulated to allow our survival. In order to make homeostasis much more visual, let's look at five more examples (in addition to those already seen hunger, thirst, pulse and cardiorespiratory rhythm or blood coagulation) of elements that are regulated and that allow the proper functioning of our system.
1. Cellular metabolism
The cellular metabolism is undoubtedly the process that requires more regulation in order to keep us alive. And is that our cells are very delicate and need to be in a very specific environment.
It is necessary that levels of different elements and ions of elements such as sodium , potassium or calcium, as well as the levels of intracellular fluid and extracellular fluid, are correctly regulated in order that the cells can exercise their functions and remain alive.
2. Body temperature
Another bodily mechanism that is continuously regulated is the internal temperature of the body. The correct functioning of our tissues and organs can be affected by excessive cold or heat , to the point of being able to lead to death by hypothermia or hyperthermia.
Fortunately, our body is able to maintain the temperature by means of a homeostatic process in which, if there is excess internal temperature, the body reacts with a decrease in physical activity, discomfort and sweating (whose objective is to reduce the temperature) or with an increase in activity, the generation of tremors, the consumption of calories , withdrawal of blood from the secondary areas to direct it to the vital areas and the search for heat in the case of lack of sufficient temperature.
3. Autonomic nervous system
The functioning of the autonomic nervous system is another clear example of homeostasis.
The sympathetic system allows the organism to prepare itself for the action and fight or flight reactions in order to survive, generating a much greater energy consumption to be able to carry out the necessary actions, while the parasympathetic system allows us to reduce activity and activation in order to replenish the energies or prevent an energy waste.
An example of deregulation it would occur in chronic stress problems , in which the sympathetic system would be excessively activated continuously.
4. Regulation of glucose
In this case, our body acts in such a way that it allows the sugar to be transformed into fats and stored thanks to insulin, whereas when it becomes necessary to use glucose from the body we secrete glucagon in order to transform fats into sugar. The clearest example of dysregulation occurs in diabetes .
5. Hormonal regulation
As well endocrine functioning It must be regulated. In fact, many of the behaviors that lead to the external generation of homeostasis, such as feelings of hunger or thirst, sexual desire or stress, depend to different degrees on this system.
A natural and non-pathological example would be found in the female menstrual cycle , as well as in the dysregulation that menopause would entail at first.
- Hardy, R.M. (1979). Homeostasis Biology notebooks. Omega: Barcelona.
- Guyton, A.C. & Hall, J.E. (2016). Treaty of Medical Physiology. 13th ed. Elsevier
- García, A. (2016). Homeostasis: regulation and control. Autonomous Mexico State University. School of Medicine.