Body homeostasis: what it is, and types of homeostatic processes

We are hungry and we eat, because our body warns us that we are lacking nutrients. We are thirsty and we drink, because we are in the process of dehydration and our body needs water to function well. Our pulse and respiration accelerate in an extremely activating situation and subsequently we reassure us, because we are no longer exposed to the situation that requires the use of Energy.

If we observe all these relationships, we can realize 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, so we carry out different processes to achieve it. We are talking about body homeostasis, which we are going to talk about throughout this article.

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What is body homeostasis?

We understand body homeostasis as 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.

Maintaining this balance is essential, since the activation or maintenance of different body processes require energy, which in turn requires elements to be used as fuel. Failure to have 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 based on the existence of changes that can occur both within the body how to come from abroad, also employing mechanisms of action that link both environments (for example, hunger makes us eat).

The concept of body homeostasis, developed by Bernard but christened by Cannon, does not speak to us of a situation in which the body remains unchanged in a position in which there are always the same parameters, but rather of a dynamic balance between states that allow the values ​​of the different components of our body to remain relatively stable, thanks to various biological mechanisms prepared to such an end.

In this sense, it must be taken into account that living beings can withstand 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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It's components

For homeostasis to exist, the existence of three fundamental elements is necessary.

In the first place, the existence of some type of elements that acts as a sensor is necessary, a receiver that allows that the organism captures the existing levels in the parameter or element that must remain in equilibrium.

In second place there must be some kind of control, a trigger that manages to make action necessary when certain levels are reached.

Third and last, it is essential that there is some type of mechanism that allows a response or action to be taken. Once the control mechanism warns that the value of the variable or factor in question reaches the level of imbalance.

Processes to balance the body

The homeostatic regulation process is complex and the mechanisms that participate in it are diverse. We can specifically highlight three of them: two of them are purely biological, while the third is more related to neuronal activity and behavior.

Negative feedback

Feedback or negative feedback is probably the mechanism of action of homeostasis that seems to have the most logical and that is the easiest to observe and understand.

This mechanism is based on the fact that given the detection of a certain level of a specific parameter that is far from normal values, a response is carried out that aims to return said parameter to previous stability.

Examples of this are those provided in the introduction to this article. In addition, it must be taken into account 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 body detects a lack of it or the need to urinate if there is an excess.

Positive feedback

Another of the processes necessary to maintain body homeostasis may, in fact, seem counterintuitive. It is about positive feedback, which is characterized by generating an increase in amplification of unbalancing stimuli, accelerating changes.

This process can be risky and even pose a danger to survival, but although it causes the body to wander even further of what you would initially do from the balanced basal state, has its usefulness: it may be necessary to give this feedback or to move the baseline state to a more optimal situation for survival or to achieve long-term return to initial situations.

Examples of this occur in blood clotting in the event of an injury, which becomes faster and faster and makes it easier to stop a hemorrhage.

Prefeeding

Feedback supposes that upon the arrival of a specific signal the organism generates some type of action that allows it to react to the existence of variations.

But this 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 forefeeding, and at the biological level we found it more linked to behavior and the capacity for association, as well as instinctual acts.

5 homeostatic processes that occur in our body

We have discussed body homeostasis as a general thing that may sound abstract to most readers (although several examples have been provided).

But there are multiple 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 the already seen hunger, thirst, pulse and rhythm cardiorespiratory or blood coagulation) of elements that are regulated and that allow the correct functioning of our system.

1. Cellular metabolism

Cellular metabolism is undoubtedly the process that needs the most 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 are properly regulated so that cells can exercise their functions and remain with life.

2. Body temperature

Another body mechanism that is continuously regulated is the internal body temperature. The correct functioning of our tissues and organs can be affected by excessive cold or heat, to the point of being able to lead us to death from hypothermia or hyperthermia.

Fortunately our body is able to maintain temperature through a homeostatic process in which if there is excess internal temperature the The body reacts with a decrease in physical activity, discomfort and sweating (aimed at reducing the temperature) or with an increase in activity, the generation of tremors, the consumption of calories, withdrawal of blood from secondary areas to direct it to vital areas and the search for heat in the case of lack of sufficient temperature.

3. Autonomic nervous system

The operation of the autonomic nervous system it is another clear example of homeostasis.

The sympathetic system allows the body to prepare for performance and fight or flight reactions in order to survive, generating a much higher energy consumption to be able to carry out the actions that are necessary, while the parasympathetic systemallows us to reduce activity and activation in order to replenish energy or prevent energy waste.

An example of dysregulation would occur in chronic stress problems, in which the sympathetic system it would be excessively activated on a continuous basis.

4. Glucose regulation

In this case, our body acts in such a way that it allows sugar to be transformed into fat and stored thanks to the insulin, while when the use of glucose by the body is necessary, we secrete glucagon in order to transform fats in sugar. The clearest example of dysregulation occurs in diabetes.

5. Hormonal regulation

Also endocrine functioning It must be regulated. In fact, many of the behaviors that lead to externally generate homeostasis, such as the sensation of hunger or thirst, sexual desire or stress depend to different degrees on this system.

We would find a natural and non-pathological example in the female menstrual cycle, as well as in the dysregulation that menopause would entail at first.

Bibliographic references:

• Hardy, R.M. (1979). Homeostasis. Biology notebooks. Omega: Barcelona.
• Guyton, A.C. & Hall, J.E. (2016). Treaty of Medical Physiology. 13th ed. Elsevier.
• Garcia, A. (2016). Homeostasis: regulation and control. Autonomous Mexico State University. School of Medicine.