The basic structural and functional unit of the living organism is the cell. For the performance of its functions, each cell needs a suitable surrounding environment that provides relative persistence of nutrient intake, water, salt, temperature, acidity, and so on.
The extracellular fluid medium(ECF)
In the course of evolutionary evolution of multi-cellular organisms, the so-called extracellular fluid medium is formed, which is the internal liquid medium for the organism. Maintaining an equilibrium in ongoing exchange processes is a necessary condition for life.
Under homeostasis is meant relative stability of the basic physiological parameters – volume of blood, its constituents, body temperature, blood pressure, and so on. Homeostasis means the persistence of all the basic parameters of the body. They remain constant despite the continuous exchange of substances and energy between the extracellular and intra-cellular liquid media.
This relatively constant state is characterized by static rather than dynamic. It is achieved by reconciling the basic physiological processes in the body.
The self maintenance of homeostasis
Maintaining homeostasis is a must for the normal functioning of all organs and systems together. The living organism has regulatory mechanisms that make it relatively independent of environmental changes. It is therefore a kind of self-regulating system.
If the disturbances in homeostasis are so pronounced that they are incompatible with the activity of a vital organ, then death may occur.
Nervous & humor system for homeostasis
There are two main systems that are responsible for providing homeostasis – this is the nervous and humoral system. The transmission of information and regulatory influence in the humoral system is through specific chemicals – hormones, and in the nervous system – by signals (impulses).
Each regulatory system has input and output. If there is no connection between the two, the system is called open. An example of such a system is the neuron – through its terminal ends it perceives input signals and links them to another unit.
With closed systems, a closed-loop circle is formed, which counteracts the initial changes that are subject to regulation – feedback. It provides dynamic regulation.