Difference Between Plasma and Tissue Fluid

The key difference between plasma and tissue fluid is that plasma is the fluid that bathes blood cells and platelets while tissue fluid is the fluid that bathes cells of the tissues.

There are two types of fluids present in our body. They are intracellular fluid and extracellular fluid. Intracellular fluid is present inside the cells while extracellular fluid is present outside the cells. Plasma and tissue fluid are two types of extracellular fluids. Plasma, also known as blood plasma, is the fluid found within the blood vessels. In contrast, tissue fluid is the fluid found between tissue cells.

CONTENTS

1. Overview and Key Difference
2. What is Plasma 
3. What is Tissue Fluid
4. Similarities Between Plasma and Tissue Fluid
5. Side by Side Comparison – Plasma vs Tissue Fluid in Tabular Form
6. Summary

What is Plasma?

Plasma is the fluid that surrounds blood cells and platelets. It circulates throughout the body via the circulatory system. It is a type of extracellular fluid. Out of the total volume of blood, 55% is blood plasma.

The major component of plasma is water. There is 90% water in plasma. Blood plasma is a straw colour liquid. It contains oxygen, carbon dioxide, glucose, amino acids, salts, hormones, plasma proteins, etc.  It acts as a protein reserve of the human body. Furthermore, it helps to protect the body from infections while keeping the electrolytic balance.

What is Tissue Fluid?

Tissue fluid, also known as interstitial fluid, is the second type of extracellular fluid found between the cells of tissues. In fact, it bathes tissue cells. Plasma forms the tissue fluid from the substances that ultrafilter from the capillaries into the intercellular spaces.  Tissue fluid delivers nutrients and oxygen to the cells and removes wastes, metabolites and carbon dioxide from the cells. Furthermore, tissue fluid acts as a reservoir of water, salts, nutrition, etc.

Moreover, tissue fluid contains amino acids, sugars, fatty acids, co-enzymes, hormones, neurotransmitters, salts and waste material from the cells, etc. A big portion of the tissue fluid returns to the plasma while the remaining tissue fluid goes to the lymph vessels.

What are the Similarities Between Plasma and Tissue Fluid?

• Plasma and tissue fluid are extracellular fluids.
• They contain water, ions and solutes.
• Tissue fluid is formed from the plasma.
• Tissue fluid normally returns back to the plasma.

What is the Difference Between Plasma and Tissue Fluid?

Plasma and tissue fluid are two major types of extracellular fluids. Plasma is the liquid that bathes blood cells within the blood vessels while tissue fluid is the liquid that bathes cells of the tissues. Thus, this is the key difference between plasma and tissue fluid. Compared to plasma, tissue fluid accounts for a higher percentage from the extracellular fluid. Another important difference between plasma and tissue fluid is that plasma contains more proteins than the tissue fluid.

Summary – Plasma vs Tissue Fluid

Plasma is the liquid portion of the blood that bathes blood cells and platelets. It is a straw colour liquid. Furthermore, it contains proteins, aiding in blood coagulation. Moreover, it facilitates the transportation of nutrients and gases throughout the body. Tissue fluid, on the other hand, is the fluid that bathes cells of the tissues. It originates from the substances of plasma. Tissue fluid brings nutrients and oxygen to cells and removes wastes from the cells. This is a summary of the difference between plasma and tissue fluid.

Reference:

1. Yawn, David H. “Plasma.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., Available here.
2.“Tissue Fluid.” A Dictionary of Biology, Encyclopedia.com, 2019, Available here.

Image Courtesy:

1. “Blood-centrifugation-scheme” By KnuteKnudsen at English Wikipedia (CC BY 3.0) via Commons Wikimedia
2. “Diagram of a lymphatic capillary CRUK 023” By Cancer Research UK – Original email from CRUK (CC BY-SA 4.0) via Commons Wikimedia