The key difference between blood and plasma is that blood serves as the primary bodily fluid, facilitating the transport of vital nutrients, oxygen, carbon dioxide, and waste materials to and from cells while, plasma the yellowish liquid portion of blood, accounts for 55% of the total blood volume.
What Is Blood?
Blood is the fluid coursing through the vessels of a circulatory system. In human beings, it encompasses plasma, which constitutes the liquid element, along with blood cells—comprising both red and white types—and cell fragments termed platelets.
Plasma
Plasma, being the predominant constituent of blood, primarily comprises water, interspersed with proteins, ions, nutrients, and waste materials.
Red blood cells
Red blood cells serve the vital function of transporting oxygen and carbon dioxide, while platelets play a crucial role in blood coagulation.
White blood cells
White blood cells form a crucial part of the immune system, actively engaging in immune responses.
Platelets
Cells and platelets collectively constitute around ___ percent of human blood, with plasma comprising the remaining ___ percent. The accompanying diagram illustrates red blood cells, various types of white blood cells (distinguished by their larger size and purple hue), and platelets.
What is Plasma?
Plasma can be described as the liquid component of blood, found outside the cells, with a transparent or pale yellow appearance. It primarily consists of clotting factors and various protein molecules, constituting approximately 50 to 55 percent of the total blood volume.
Composition of Plasma:
The composition of blood plasma predominantly comprises 80 to 90 percent water, with the remaining 10 percent consisting of salts, lipids, nutrients, enzymes, and hormones.
Color of Blood Plasma:
Blood plasma typically exhibits hues ranging from pale yellow to dark yellow, occasionally appearing straw-colored.
Constituents of Plasma in Blood Cells:
Within plasma, proteins such as immunoglobulins, clotting factors, and fibrinogen are present. These proteins play vital roles in blood coagulation and help maintain serum osmotic pressure.
Definition of Plasma Proteins:
Plasma proteins, also referred to as blood proteins, fulfill various functions, including transporting hormones, lipids, vitamins, and minerals, and activating the immune system. Additionally, some plasma proteins serve as protease inhibitors, complement components, enzymes, or precursors to kinin.
Names of Plasma Proteins:
The names of blood plasma proteins, along with their normal values, are as follows:
- Serum globulin (2 – 3.5 g/dL)
- Serum albumin (3.5 – 5.5 g/dL)
- Fibrinogen (0.2 – 0.4 g/dL)
Serum exclusively contains globulin and albumin, as fibrinogen is converted into fibrin during the process of blood clotting.
Blood vs Plasma
The basic difference between blood and plasma is given below:
| Feature | Blood | Plasma |
|---|---|---|
| Definition | Fluid circulating in the vessels of the circulatory system. | Extracellular liquid portion of blood. |
| Composition | Blood cells (red and white), platelets. | Water, salts, lipids, nutrients, enzymes, hormones, proteins (clotting factors, immunoglobulins, etc.). |
| Color | Red due to hemoglobin in red blood cells. | Transparent or pale yellow. |
| Volume | Makes up about 45% of total blood volume. | Constitutes 50-55% of total blood volume. |
| Function | Transports oxygen, nutrients, hormones, and waste products. | Maintains osmotic pressure, transports various substances, aids in blood clotting. |
| Presence of Cells/Platelets | Contains blood cells and platelets. | Does not contain blood cells or platelets; they are removed during plasma isolation. |
| Role of Fibrinogen | Fibrinogen is present, involved in blood clotting. | Fibrinogen is present, plays a role in blood clotting, but converted into fibrin during clot formation. |