WHAT IS CREATION? (BIOLOGY) - BIOLOGY - 2024

Creation is a term used to describe the shape of an object or structure that has scalloped edges or the surface is irregular. Generally the term is applied to the hematological phenomenon where the red blood cells or red blood cells are subjected to a hypertonic solution. As a consequence, the cell proceeds to release the water that is inside, causing flaccidity and could lead to cell destruction.

The opposite phenomenon occurs when blood cells are exposed to a hypotonic environment - where solutes are less than the inside of the cell. In this case, the cell bursts, a product of the accumulation of water and is called hemolysis.

Osmotic behavior of red blood cells. Source: LadyofHats In addition, creation is a term used to describe certain characteristics of red blood cells, where they exhibit a kind of projection on their surface.

In most cases, the observation of these hematological irregularities are a technical artifact, while in some patients they do represent signs of some pathology.

What is Creation?

In biology, the concept of creation is broad and can be applied to different settings. In this article we will focus on describing two of its meanings in the area of ​​hematology: one of these is the loss of water by red blood cells and the other refers to an irregular characteristic of these cells.

Osmotic behavior of erythrocytes

The movement of water and the concentration of solutes in and out of cells are parameters that lead the processes of osmosis and diffusion, which play a vital role in biological systems. Before describing the phenomenon of creation, we must understand two key concepts: diffusion and osmosis.

-Basic concepts of passive transport

Diffusion

The movement of particles from a relatively more concentrated area to a less concentrated one - down the concentration gradient - is called diffusion. For example, when carbon dioxide diffuses to the outside of the cell or the movement of sodium ions into the cell during the nerve impulse.

Osmosis

In the same way, osmosis occurs when water is the substance that diffuses through a semi-permeable membrane - such as biological membranes - in the presence of a solute. In this case, the solute cannot diffuse through the membrane, but water can.

There are countless examples of osmosis. In fact, it is a phenomenon that extends to our daily lives. When we prepare a pickle of vegetables, we subject them to a very concentrated solution of salt, and they tend to lose water and take on a wrinkled appearance.

-Erythrocyte osmosis

In cells, membranes behave like a semi-permeable barrier. It is an essential component, since cells need to delimit their space and they do so with this lipid and dynamic structure.

The membrane of red blood cells or erythrocytes are semipermeable structures and the direction of water movement will depend on the internal and external concentration of this system.

There is a terminology to refer to these parameters: when the solution is more concentrated than the interior of the cell, we say that it is hypertonic with respect to the latter. In contrast, when the external concentration is lower it is a hypotonic solution. If the concentration is equal in both compartments, the term isotonic is used.

Creation

Like the pickled vegetables in our previous example, when we put red blood cells in a hypertonic solution, the water tends to flow out of the cell. As a consequence of this, the cell wrinkles and loses its turgor. We call this phenomenon creation.

The analogous concept of cellular dehydration in plant structures is known as plasmolysis. During water loss, the cell wall remains intact, while the membrane wrinkles and organelles progressively accumulate in the center.

Hemolysis

Following this logic, the reverse phenomenon of creation occurs when we subject red blood cells to a hypotonic solution. Here, the water will enter the cell and could cause cell rupture, leading to hemolysis.

Importance of Creation and Hemollosis in Medicine

In many medical settings, it is necessary to give the patient intravenous infusions. For example, if an individual is unable to feed normally by oral route, it will be necessary to feed him through a nutrient solution intravenously - that is, the supply of food occurs directly to the veins.

The concentration of the body fluids must be known to provide a solution of equal concentration (isotonic), to avoid creation or hemolysis.

Creation and the shape of erythrocytes

The second meaning of the term creation is used to describe the peculiar characteristic of red blood cells to develop numerous extensions in regular and short patterns throughout their surface. When these cells present this condition, they resemble a sea urchin or a porcupine, which is why the phenomenon is also called echinocytosis.

Creation in erythrocytes was initially evidenced by Eric Ponder, who describes it as a phenomenon of transformation of the disc into a sphere with multiple projections.

Causes of Creation

There are multiple causes that can explain the phenomenon of creation in erythrocytes. In some blood films it is common to observe crenated cells, not only in individuals with special hematological conditions, they also appear in healthy individuals.

Artifacts in the laboratory

Creation is usually a technical artifact, the product of a prolonged rest of the sample overnight before performing the procedure required to observe the blood in the laboratory.

They also usually appear when erythrocytes are separated from plasma and suspended in a saline solution at 9 g / l. Similarly, the presence of fats on the slide on which the sample is deposited causes the observation of crenate cells.

The use of certain chemical compounds also leads to cell creation. The use of EDTA has been shown to produce a marked creation pattern.

Medical conditions

In case the extension of the sample is performed with strawberry blood, the creation represents a medical alert that must be considered.

The phenomenon is generally observed in patients with medical conditions such as uremia (accumulation of toxic products in the blood) or in individuals subjected to extracorporeal circulation. Creation has also been noted to be common in preterm infants after exchange transfusion.

References

1. Brailsford, JD, Korpman, RA, & Bull, BS (1980). Crenation and cupping of the red cell: A new theoretical approach. Part II. Cupping. Journal of theoretical biology, 86 (3), 531-546.
2. Brown, TL, LeMay Jr, HE, Bursten, BE, & Burdge, JR (2004). Chemistry Pearson Education.
3. Guyton, AC, & Hall, JE (2012). Compendium of Medical Physiology. Elsevier.
4. Lewis, SM, Bain, BJ, & Bates, I. (2008). Practical hematology. Elsevier Spain.
5. Ponder, E. (1944). The osmotic behavior of crenated red cells. The Journal of general physiology, 27 (4), 273-285.
6. Rebar, AH (2002). Manual of hematology of dogs and cats. Multimedica Ed. Vet..
7. Thibodeau, GA, Patton, KT, & Howard, K. (1998). Structure and Function. Elsevier Spain.
8. Wintrobe, MM (2008). Wintrobe's clinical hematology. Lippincott Williams & Wilkins.