The role of interstitial fluid, what is interstitial fluid

Tissue fluid. The body fluids that exist in the interstitial spaces are the internal environment in which cells live. It is a medium for the exchange of substances between blood and tissue cells.

The vast majority of tissue fluid is gelatinous and does not flow freely, so it does not flow to the low-hanging parts of the body due to gravity; The injection needle is inserted into the interstitial space, and the interstitial fluid cannot be aspirated. However, the diffuse movement of water in the gel and the dissolved in water and various solute molecules is not hindered by the gel, and can still exchange substances with the blood and intracellular fluid. The matrix of the gel is mainly hyaluronic acid.

A small portion of interstitial fluid adjacent to the capillaries is sol and flows freely. Interstitial fluid is produced by plasma filtering through the wall of the capillary artery, and at the capillary venous end, most of it is absorbed back into the blood through the wall. In addition to macromolecular proteins, water and other small molecules in plasma can filter through the capillary wall to complete the exchange of substances between blood and tissue fluid.

The power of filtration is the effective filtration pressure.

1.Interstitial fluid is formed by the filtration of plasma through the capillary wall, and its composition is basically the same as that of plasma, except that it does not contain macromolecular proteins.

2.The motive force by which plasma filters through capillaries to form interstitial fluid – effective filtration pressure.

Effective filtration pressure = (capillary blood pressure + interstitial fluid colloidal osmotic pressure) - (plasma colloidal osmotic pressure + histolicomic hydrostatic pressure).

3.Factors influencing interstitial fluid production:

1) Effective filter pressure;

2) capillary permeability;

3) Venous and lymphatic reflux, etc.

Interstitial fluid is produced by the filtration of blood through the capillary wall, and its production depends mainly on the effective filtration pressure. Effective filtration pressure for the generation of interstitial fluid = (capillary pressure + colloidal osmotic pressure of interstitial fluid) - (plasma colloidal osmotic pressure + hydrostatic pressure of interstitial fluid). Because intracapillary blood pressure at the proximal arteriole end is higher than that in the capillaries at the proximal venous end of the capillaries, interstitial fluid is filtered out at the capillary arterial end and reabsorbed at the venous end.

In addition, a small amount of tissue fluid enters the capillary lymphatic vessels, forming lymphatic fluid.

Tissue fluid. It provides a place for the exchange of waste and nutrients for the cells, and the cells live in the interstitial fluid, so the cells cannot live without the interstitial fluid. Oxygen enters the human body first into the bloodstream and then through the interstitial fluid into the cells, the reason why it passes through the interstitial fluid is because the cells are soaked in the interstitial fluid, and they cannot enter the cells without the interstitial fluid.

You say that there are solutes in the interstitial fluid, most of the solutes in the interstitial fluid, and there are very few proteins, and compared to plasma with more protein, less protein in plasma will cause osmotic pressure.

the difference, thus edema.

Interstitial fluid is the fluid that exists between cells, also known as intercellular fluid. Interstitial fluid exists in large quantities in animals and plants, and is a liquid environment in which ordinary cells live directly, and can exchange substances with cells.

Cells are infiltrated in the interstitial fluid and can exchange substances with the interstitial fluid, which is a necessary condition for the metabolism of ordinary cells. In addition, the interstitial fluid buffers and protects the cells.

Generation of tissue fluid:

Under normal circumstances, interstitial fluid is continuously produced from the arterial end of the capillary, and at the same time, part of the interstitial fluid returns to the capillary through the capillary venous end, and the other part of the interstitial fluid flows back into the blood circulation through the lymphatic vessels.

Interstitial fluid is formed by the filtration of plasma through the walls of capillaries. The contrast between the two forces, filtration and reabsorption, determines the direction in which the liquid is moving. Specifically, the direction in which the fluid moves inside and outside the capillary wall depends on four factors, namely capillary blood pressure, interstitial fluid hydrostatic pressure, plasma colloidal osmolality, and interstitial fluid colloidal osmolality.

Interstitial fluid can enter cells to become intracellular fluid, it can also enter the bloodstream, and it can also enter lymphatic vessels to become lymphatic fluid.

Tissue fluid and plasma flow to each other.

Interstitial fluid is formed by plasma filtering through the capillary wall into the interstitial space. The principle of its formation is filtration, and the general capillary wall can freely filter the plasma components except protein molecules, so the direction and speed of the liquid through the capillary wall depend on the following four factors, which together constitute the effective filtration pressure of the interstitial fluid production file: Effective filtration pressure generated by interstitial fluid (capillary blood pressure Colloidal osmotic pressure of interstitial fluid) (plasma colloidal osmotic pressure Hydrostatic pressure of interstitial fluid) At the capillary arterial end, the effective filtration pressure generated by interstitial fluid is positive as the family, The liquid components of the plasma are filtered out by the blood vessels to form interstitial fluid; As blood flows through the capillaries, the blood pressure gradually decreases, so that after reaching the middle of the capillaries, the effective filtration pressure generated by the interstitial fluid becomes negative, and the liquid components in the interstitial fluid flow back into the plasma through the capillary wall.

The factors that affect the formation of interstitial fluid are:1Capillary blood pressure:

Positive correlation. For example, in the case of right-sided heart failure, retrograde increases tissue capillary blood pressure, increases the effective filtration pressure of interstitial fluid production, and increases interstitial fluid production. 2.

Obstruction of local venous or lymphatic return, resulting in local edema. 4.Permeability of capillary walls:

When the permeability of the capillary wall increases, some plasma proteins are filtered out of the plasma to the interstitial fluid, resulting in a decrease in plasma colloidal osmotic pressure and an increase in the colloidal osmotic pressure of interstitial fluid.