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What Is Crenation?

Mary McMahon
Updated: Mar 03, 2024

Crenation is a phenomenon which occurs when cells of animal origin are exposed to a hypertonic solution, meaning that the solution which bathes the cells has a high concentration of solutes. In crenation, the cells shrink and their shapes become distorted, often with a ruffled or scalloped edge. The change in cell shape can be seen in microscopy of the cells, and can be a sign that someone is experiencing a medical problem. These cells may die as a result of impairments in cell function.

When animal cells are bathed in a hypertonic solution, it draws water out of the cells through a process known as osmosis. Water flows from areas of low solute concentration to areas of high solute concentration in an effort to stabilize the difference between the two solutions. Sometimes, particles small enough to pass through the cell walls may be drawn out along with the water, and in other cases, they remain behind because they are too big to move through the cell membrane.

As the water leaves the cell, it starts to shrivel, since much of its shape is due to the water inside which keeps it plump. Red blood cells display the results of crenation more markedly, transitioning from a round to a spiky shape. The term “crenation” is a reference to the scalloped shape of a crenated cell. Without water, the cell will have trouble functioning.

One reason the phenomenon occurs is dehydration. When the body is not ingesting more water, the fluid which bathes cells can become hypertonic, rather than isotonic, in which the extracellular fluid and fluid inside the cells has the same concentration of solutes. Crenation can also be associated with some disease processes. The same process is known as plasmolysis in plant cells because the rigid cell wall prevents the cell from changing shape as water is lost.

If the solution is hypotonic, with the fluid inside the cells having a higher concentration of solutes than the fluid which surrounds the cells, water will pass through the cell wall and into the cell as a result of osmosis. If enough water is absorbed, the cell will burst and release its contents. This can be a very serious consequence of drinking large amounts of water without urinating, as the kidneys cannot keep the balance of fluids in the body stable when they cannot eliminate urine.

How Can Osmosis Cause Crenation of Red Blood Cells?

Osmosis plays an important role in many essential functions of the body:

  • It helps tissues receive oxygen
  • It removes waste from the bloodstream
  • It aids in digestion so you can absorb essential nutrients from your food

Even though it happens on a microscopic level, osmosis is powerful enough to maintain life or lead to death.

Osmosis and Homeostasis

Osmosis assists millions of cells in receiving or transporting molecules so that you can maintain homeostasis, the constant balance that allows your body systems to function properly. Without it, you could not survive. Because balance is essential for overall physical health, it is easy to see how it's also necessary at the cellular level. Osmosis is critical for protecting and fostering healthy cells. Most of the time, this process helps prevent serious issues from occurring, but it can also lead to potential damage and even the destruction of red blood cells.

Understanding Solutes

A solute is any substance that can be completely dissolved in a liquid to form a solution. One of the most common examples is salt, but many others exist. Osmosis occurs when there is a high concentration gradient between the intracellular (inside of the cell) and extracellular (outside of the cell) fluids and solutes. In other words, the number of solutes inside of a red blood cell is significantly higher than in the fluid surrounding it, or vice versa. In an attempt to maintain equilibrium, fluid will travel from the area with the highest concentration of solutes to the area with the lowest concentration.

Most of the time, this transport of fluids into or out of red blood cells helps them maintain homeostasis. However, if the solution surrounding the cells has an abnormally high or low level of solutes, problems will arise. Fluids can rush into the cells, eventually causing them to burst and die. Fluids can also rush out, resulting in crenation.

What Causes Crenation of Red Blood Cells?

One of the most common reasons for crenation to occur is a high level of solutes in the blood. This can happen for a variety of reasons, including:

  • Chronic or severe dehydration
  • A pH imbalance within the bloodstream
  • High concentrations of calcium in the blood
  • Using certain drugs, supplements, or medications
  • Vitamin deficiencies
  • Chemotherapy treatment
  • Poorly functioning kidneys

Drinking more water may be the first step for many patients, while others may need treatments to address underlying issues that are leading to excess solutes in the blood. Changes in diet, medication, or supplement use can also be helpful.

Sometimes crenation occurs not because solute concentration is abnormal, but because there is an issue with the cell's semipermeable membrane. In this situation, the membrane cannot function as needed to maintain balance by allowing the right materials to pass through while prohibiting others. Crenation can often result.

Most of the time, crenation caused by unhealthy cell membranes is much more serious because it can be difficult or impossible to treat. While it can be caused by liver problems, digestive issues, or vitamin deficiencies, it can also be the result of an irreversible genetic condition.

Is Crenation Dangerous?

Some crenation happens on a regular basis. Most of the time, unwanted crenation can easily be reversed with some simple lifestyle changes or medical treatments. However, only a doctor can help determine whether or not red blood cell crenation is truly problematic and what type of treatment is required.

It is important to remember that a normal, healthy body is constantly making new red blood cells by the millions on a daily basis. This helps replace other cells as they die. Typically, a red blood cell only lives for about 120 days. Even so, excessive crenation can be a problem. Without enough healthy red blood cells to effectively transport oxygen throughout the body, you could start to experience issues with most of your body's major systems.

Combatting Crenation with a Healthy Lifestyle

While it is not possible for everyone to prevent excessive crenation completely, there are ways to help reduce the risks of developing this issue. Drinking plenty of water is a good place to start, as it helps maintain a healthy solute balance while encouraging the body to filter out waste. Eating a nutrient-rich diet that aids in kidney function can also be beneficial. Some foods that are recommended for healthier kidneys include:

  • Cauliflower
  • Apples
  • Red bell peppers
  • Garlic
  • Berries
  • Fish
  • Egg whites
  • Olive oil
  • Cabbage
  • Onions

Anything that promotes kidney function and the effective filtering of the blood can help prevent crenation. In addition, be mindful of the supplements you are taking. Always consult a physician before starting a new vitamin regimen.

The Health Board is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Mary McMahon
By Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a The Health Board researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Discussion Comments
By Glasis — On Feb 17, 2014

Erythrocytes are the most common part of blood in vertebrates. It is the primary mode of transportation of oxygen through the body.

These cells travel to the gills of sea creatures or lungs of land creatures and soak up the oxygen. Inside these cells is iron and with a chemical reaction between the iron and oxygen the oxygen is kept safe in the cell until released to the final delivery point.

Erythrocytes live for 100 to 120 days and are then recycled. The human body generates over two million of them per second.

About one quarter of the cells in the human body are red blood cells.

Red blood cells (as part of whole blood) can be donated, to save lives of people suffering a shortage of healthy blood cells. Donating red blood cells can be done every sixty days with little disruption to the human body.

By Ariestack — On Feb 17, 2014
Too much of any good thing can be bad, even water. It seems that red blood cell crenation can happen if the kidneys cannot keep up with the intake of water. Also, the brain can swell. Who would have thought even water could be a troublesome thing?
Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a...

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