The key difference between plasma and interstitial fluid is that the plasma is the fluid in which the blood cells and platelets suspend while the interstitial fluid is the fluid that surrounds the cells in an organism.
Water is the main component of body fluids. Thus, the body water can be found mostly in two major compartments called intracellular fluid and extracellular fluid. Intracellular fluid lies inside the cells while extracellular fluid resides outside the cells. Intracellular fluid accounts for a higher percentage compared to the extracellular fluid. On the other hand, the extracellular fluid has two main types; blood plasma and interstitial fluid. Among them, plasma occupies for a small percentage compared to the interstitial fluid.
CONTENTS
1. Overview and Key Difference
2. What is Plasma
3. What is Interstitial Fluid
4. Similarities Between Plasma and Interstitial Fluid
5. Side by Side Comparison – Plasma vs Interstitial Fluid in Tabular Form
6. Summary
What is Plasma?
Plasma is one of the two components of the extracellular fluid. Therefore, plasma or blood plasma is the fluid found within the vascular system (blood circulatory system). It is the rice straw colour liquid that circulates within the blood vessels. Also, from the total blood volume, plasma accounts for 55% volume. Thus, it has different suspended cells such as blood cells and platelets, etc.
Figure 01: Plasma
Furthermore, it contains many dissolved substances such as oxygen, carbon dioxide, salts, amino acids, fatty acids, hormones, and plasma proteins. Also, we can find a tiny difference in concentrations of cations and anions in plasma than in interstitial fluid. Besides, plasma acts as a protein reserve of the human body. Further, it helps to protect the body from infections while keeping the electrolytic balance.
What is Interstitial Fluid?
Interstitial fluid is the second major component of the extracellular fluid. Hence, it surrounds all the cells in an organism. In simple words, interstitial fluid is the liquid in which cells are submerged. When compared to plasma, interstitial fluid occupies a higher percentage of the extracellular fluid. But when compared to the total body fluids, interstitial fluid occupies for only 26%.
Figure 02: Interstitial Fluid
Generally, due to the difficulty of separation, interstitial fluid and lymph have been included in a single component. Hence, the interstitial fluid can be considered as the ultrafiltrate of plasma. Moreover, interstitial fluid is the tissue fluid that transports nutrients from the blood to the cells, and carbon dioxide and other wastes back to the blood from the cells.
What are the Similarities Between Plasma and Interstitial Fluid?
- Plasma and interstitial fluid are extracellular fluids.
- They reside outside the body cells.
- Also, both types account for less percentage than the intracellular fluid in our body.
- Furthermore, water is the main component of both fluids.
- Besides, both these fluids are very important for the functioning of an organism.
What is the Difference Between Plasma and Interstitial Fluid?
The key difference between plasma and interstitial fluid is that the plasma lies within the blood vessels and it is the liquid portion of the blood while the interstitial fluid lies between the cells of the tissues. Another difference between plasma and interstitial fluid is the protein concentration. That is, the plasma contains higher protein concentration than the interstitial fluid. However, from the total volume of extracellular fluids, interstitial fluid accounts for a higher percentage than the plasma.
The below infographic tabulates the difference between plasma and interstitial fluid in more detail.
Summary – Plasma vs Interstitial Fluid
Plasma and interstitial fluid are two major types of extracellular fluids in our body. They distinguished from the intracellular fluid since they reside outside the body cells. Plasma is the liquid portion of the blood. It is pale yellow colour fluid. Blood cells and platelets are suspended in the plasma. Thus, it has a higher concentration of dissolved oxygen. On the other hand, interstitial fluid is the liquid which surrounds and bathes all the body cells. It accounts for a higher percentage from the extracellular fluid than the plasma. The dissolved oxygen concentration is low compared to the plasma. Therefore, this is the difference between plasma and interstitial fluid.
Reference:
1.“Extracellular Fluid.” Wikipedia, Wikimedia Foundation, 2 Sept. 2018. Available here
2.“Interstitial Fluid.” NeuroImage, Academic Press. Available here
Image Courtesy:
1.”FreshFrozenPlasma”By DiverDave – Own work, (CC BY-SA 3.0) via Commons Wikimedia
2.”Illu capillary microcirculation” (Public Domain) via Commons Wikimedia