What is quasi steady state and what is the difference between steady state and unsteady state?

Two points in the sample are constant, and the temperature growth rate at each point is the same and the heat conduction state remains constant.

Chinese name: steady state English name: steady state; Homeostasis Definition 1:

The equilibrium state of the system. And the system can spontaneously return to this state after minor disturbances. Discipline:

Geography (first-level discipline); Quantitative Geography (Secondary Discipline) Definition 2: The state maintained by the system when all inputs remain constant after all transient effects have disappeared. Discipline:

Electric Power (first-level discipline); General Theory (Secondary Discipline) Definition 3: (1) The tendency of an ecosystem to resist external disturbances and maintain a relatively stable state through internal regulation. (2) The internal environment of insects is kept constant.

Discipline: Entomology (first-level discipline); Insect Ecology (Secondary Discipline) Definition 4: An ecosystem is able to maintain a stable internal state in the face of changing external conditions.

Discipline: Ecology (first-level discipline); Ecosystem Ecology (Secondary Discipline) Definition 5: A state in which the rate at which enzymes and substrates form enzyme-substrate complexes is equal to the rate at which products are formed, and the concentration of enzyme-substrate complexes remains unchanged over time.

Disciplines: Biochemistry and Molecular Biology (first-level discipline); Enzymes (secondary discipline).

Homeostasis refers to the normal organism through the regulation of various organs and systems to coordinate the activities of various organs and systems to jointly maintain a relatively stable state of the internal environment, which is the condition for the free survival of organisms.

Physical and chemical properties including temperature, osmotic pressure, pH, and various ion concentrations must always be relatively stable. Homeostasis is a dynamic process, because life activities are metabolized all the time, and the oxygen and nutrients required for life activities are obtained from the environment through the respiratory and digestive systems.

At the same time, the metabolic waste products produced in the metabolic process should be excreted from the body through the excretory organs; So change is absolute, while invariance is relative.

Significance of homeostasis:

For humans and higher animals, the homeostasis of the internal environment is a necessary condition for cells to maintain normal physiological functions and even for the body to maintain normal life activities. The homeostasis of the internal environment means that under normal circumstances, the various components and physical and chemical properties of the internal environment of the body only change within a small range.

The various metabolic activities of cells are enzymatic biochemical reactions, so the internal environment needs to have enough nutrients, oxygen and water, as well as suitable temperature, ion concentration, pH and osmotic pressure. A certain ion concentration and distribution on both sides of the cell membrane is necessary for some cells to maintain their normal excitability and bioelectrical activities.

The disruption of homeostasis in the internal environment will affect the normal progress of cell life activities, such as high fever, acidosis, hypoxia, and changes in ion concentration, which will lead to serious disorders of cell function, cause diseases, and even endanger life.

To put it simply:

Steady-state is a steady state, in an electronic circuit, before entering the steady state, it needs to go through a transient process, and then enter the steady state, when the output level is approximately constant, or high or low, if the conditions applied to this circuit do not change, then this state will continue to be maintained.

In fact, in circuits, the concept of steady state is not limited to these, such as phase, frequency, amplitude, and so on.

Steady-state generally refers to the steady state of the internal environment, and the physical and chemical properties of the internal environment are relatively constant, including temperature, pH, osmotic pressure, chemical composition, etc. Currently, the concept of homeostasis extends to other phenomena of life.

It generally refers to any physiological process that is kept in a relatively constant state through the body's own regulatory mechanism, such as the relative stability of body temperature.

Extracellular fluid is the liquid environment in which cells survive and move, known as the internal environment of the body. Extracellular fluid accounts for about 20% of body weight, of which about 3 4 is interstitial fluid, which is distributed in various tissue spaces throughout the body, and is the place where blood and cells exchange substances. 1 4 of the extracellular fluid is plasma, which is distributed in the cardiovascular system, and plasma and blood cells together constitute blood, which circulates throughout the body.

Under normal physiological conditions, the various physical and chemical properties of the internal environment are relatively stable, which is called homeostasis of the internal environment.

A state of equilibrium that no longer changes.

The body's metabolism is composed of many complex enzymatic reactions in cells, and the enzymatic reactions require mild external conditions, such as temperature, pH, etc., must be kept within the appropriate range in order for the enzymatic reactions to proceed normally. It can be seen that the homeostasis of the internal environment is a necessary condition for the body to carry out normal life activities.

When the homeostasis of the internal environment is disrupted, it causes a disorder of cell metabolism and leads to disease. For example, when the amount of calcium and phosphorus in the blood decreases, it can affect the calcification of bone tissue, which is manifested as osteomalacia in adults and rickets with impaired bone growth and ossification in children. High blood calcium can cause muscle weakness and other diseases.

When the human body exercises vigorously, the homeostasis of the internal environment is not disrupted, because of the presence of buffering substances in the human blood.

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With the development of cybernetics and other life sciences, homeostasis has not only been carefully bent to refer to the steady state of the internal environment, but also extended to a large number of physiological processes in the organism that maintain coordination and stability.

For example, the maintenance of vital functions and normal posture (upright and walking); It is also used for the steady state of different levels or levels of the body (cells, tissues, organs, systems, wholes, social groups); and a specific state that is maintained for a specific period of time, from a few milliseconds to tens of thousands of years. Homeostasis is not only physiology, but also a fundamental concept in the life sciences today.

It has important implications for a variety of disciplines, including cybernetics, genetics (homeostasis of genes), psychology (emotional homeostasis, etc.), pathology, and clinical medicine.

Systems related to internal environmental homeostasis: digestion and osmosis system, respiratory system, urinary system, circulatory system.

Are you trying to ask about physiological homeostasis? I'm a student, but the answer is relatively simple, and I don't know if it's what you want.

Homeostasis refers to the state in which the physical and chemical environment of the internal environment remains relatively stable due to the presence of the sage.

Meaning: 1. Physical and chemical factors are constant at a certain level.

2. The constant state is not fixed, the surface is a dynamic equilibrium, and it is the relative constancy of the guessed reed in small fluctuations.

Realization: Nerves. Fluid regulation.

Significance: Necessary conditions for maintaining the normal function and physiological activities of cells, organs, systems and even the whole.

Homeostasis: The physical and chemical properties of the internal environment are relatively constant, and the physical and chemical properties include Jing Burn Zen: temperature, pH, andOsmotic pressure, chemical composition, etc.

At present, the concept of homeostasis has been expanded to refer to the state in which various physiological functions and activities in the body are relatively stable under the regulation of nervous and humoral factors, from the cellular and molecular levels, the organ and system level to the overall level.

Brief introduction. Physiology will extracellular fluid.

The state in which the physicochemical properties remain relatively stable is called homeostasis. Its physicochemical properties include temperature, osmotic pressure, pH.

The concentrations of various ions should always be relatively stable.

Homeostasis is a dynamic process, because life activities are metabolized all the time, and the oxygen and nutrients needed for life activities pass through the respiratory and digestive systems.

obtained from the environment; At the same time, the metabolic waste products produced in the metabolic process should be excreted from the body through the excretory organs; So change is absolute, while invariance is relative.

The maintenance of homeostasis in the internal environment is a complex physiological process, such as the respiratory system.

Gas exchange, food intake, digestion and absorption by the digestive system, production and discharge of urine from the kidneys, pumping function and blood transport of the cardiovascular system, nervous system.

The physical and chemical properties of the internal environment remain relatively stable.

If the amplitude of the change in the physical and chemical characteristics of the environment before the inner segment is too large, exceeding the adjustment limit of the human body will lead to the disorder of human physiological functions. In the 19th century, the French physiologist Claude Bemard put forward the concept of internal environment, and said that the internal environment is relatively stable as a condition for the free survival of organisms.

The difference between steady-state and unsteady-state solving.

1. When the fluid flows in the pipeline, if the parameters related to the flow (such as velocity) change with time, then the flow of the fluid is called unsteady flow.

Although the velocity on the cross-section is different, the velocity on all the cross-sections does not change with time, and the velocity only changes with the change of the spatial position, and is independent of time, and this flow situation is called steady-state flow.

2. Comparison of the results of the two solutions:

In one case, the physical problem to be solved is steady, and theoretically the results of the convergence of the two solutions are the same or approximate. However, it should be noted that the selection of dt in the unsteady solution will affect the calculation results, and the calculation may diverge, and there must be enough computational steps to converge before it can be compared with the results of steady.

In other words, if you use the unsteady method to solve the steady flow, if the computation itself is not convergent, and the results are compared, then it will definitely not work. Generally speaking, when solving unsteady, the results of the previous period of calculation are basically not used, because there is a process of numerical convergence.

3. If the physical problem you want to solve is unsteady, then the result of using the steady solution method is a pile of garbage and has no value.

Homeostasis of the internal environment is a necessary condition for the body to carry out normal life activities, which is regulated by neurohumoral immunity, and is constantly changing, but it is in a relatively stable state.

Through regulation, the normal body makes various organs and systems coordinate their activities and jointly maintain a relatively stable state of the internal environment.

The homeostasis of the internal environment is not a fixed and unchanging state of rest, but a state of dynamic equilibrium. It is manifested that the physical and chemical properties of the internal environment only change in a small range, such as maintaining body temperature at about 37, plasma pH at about 37, blood glucose balance, etc.

Homeostasis of the internal environment is a necessary condition for cells to maintain normal physiological functions, and it is also a necessary condition for the body to maintain normal life activities, and the imbalance of homeostasis in the internal environment can lead to diseases. The maintenance of homeostasis in the internal environment depends on the stability of the functional state of various organs, especially the internal organs, the normal of various regulatory mechanisms of the body, and the role of blood bonds.

Homeostasis: The normal body makes various organs and systems coordinate their activities through regulation and jointly maintain a relatively stable state of the internal environment, which is called homeostasis.

The essence of homeostasis: the chemical composition and physical and chemical properties of the internal environment remain relatively stable.

What is homeostasis is as follows:

Homeostasis is a state of equilibrium formed by a system after reaching a certain amount of time, and various properties do not change with time. The steady state can be static steady state, that is, the equilibrium state does not change; It can also be a dynamic steady state, where the equilibrium state still changes over time, but this change is relatively slow. Homeostasis is a widespread phenomenon in nature and human society and is of great significance.

The following subparagraphs describe it in detail.

1.Classification of the system.

Systems can be divided into open systems and closed systems. The open system can exchange material, energy and information with the external environment, such as a reservoir, water can enter and exit, and the water level in the reservoir can change at any time. A closed system cannot be exchanged with the external environment, such as a closed container, and the quantity and properties of the gas in the container do not change.

Whether it is an open system or a closed system, there is a state of equilibrium such as steady state.

2.Conditions for the formation of homeostasis.

The various factors within the system interact and influence each other, thus promoting the evolution of the system towards a state of equilibrium, which is the steady state. The formation of homeostasis needs to be satisfied: the system is in a state of break-even, that is, an equilibrium state between input and output; The variables change slowly, reaching a state of equilibrium; The successes of each variable are interdependent and not independent of each other.

Sock attack. 3.Conversion of steady state to unsteady state.

Changes in the internal or external environment of the system may cause a change in the original equilibrium state of the system, that is, from a steady state to an unsteady state. This unsteady state can be short-lived, temporary, such as sudden events; It can also be long-term and persistent, such as climate change.

4.The significance of steady-state in practical applications.

Homeostasis is a widespread phenomenon in nature and human society and is of great significance. In the field of engineering, studying steady state can help design efficient, stable systems; In the field of environmental science, the study of homeostasis can help understand the evolution of ecosystems; In the economic field, the study of homeostasis can help formulate sound macroeconomic policies.

In short, it is of great significance to explore the laws and mechanisms behind homeostasis to promote social progress and development.