What is Plasma in Blood?

Plasma – Introduction

Plasma is referred to as the matrix of blood.

Blood is primarily composed of RBC (red blood cells), WBC (white blood cells), blood platelets and plasma. Among these components, plasma is the liquid component of the blood.
Table of Content:

What is Plasma? Features of Blood Plasma Functions of Blood Plasma Frequently Asked Question

What is Plasma?

Plasma definition – Plasma can be defined as an extracellular and liquid portion of blood, which is transparent and pale yellow or straw-coloured. It is mainly composed of clotting factors and other protein molecules. Overall, plasma constitutes 50 to 55 per cent of total blood volume.

Composition of plasma – Plasma in blood mainly comprises 80 to 90 per cent of water and the other 10 per cent is composed of salts, lipids, nutrients, enzymes and hormones.

Blood plasma colour – Pale to dark yellow or sometimes straw coloured.

Plasma in blood cells contains proteins, immunoglobulin, clotting factors and fibrinogen. This protein helps in coagulation factors and also maintains serum osmotic pressure.

Plasma Proteins Definition

Blood plasma contains proteins known as blood proteins or plasma proteins. They perform many tasks, such as transporting hormones, lipids, vitamins, and minerals for immune system activation. Other plasma proteins function as protease inhibitors, complement components, enzymes, or precursors to kinin.

Names of Plasma Proteins 

Blood plasma protein names and 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)

The serum contains only globulin and albumin. Fibrinogen is absent in serum because it is converted into fibrin during blood clotting.

See more: Blood Coagulation

Features of Blood Plasma

Compared to other blood cells, plasma is relatively transparent and other blood cells are freely suspended within the plasma. The constituents of blood plasma are:

  1. Plasma contains fibrinogen, immunoglobulin, electrolytes and proteins.
  2. Blood plasma is the main medium for excretory product transportation.
  3. Blood plasma has a density of approximately 1025 kg/m3, or 1.025 g/ml.
  4. Plasma is the medium of the blood, in which different types of blood cells exist.
  5. Blood plasma has a long shelf life; therefore, it can be preserved for more than a year and can be used.

Also Check: Difference between Serum and Plasma

Functions of Blood Plasma

Plasma is derived from the liquid portion of the blood and is routinely used in blood group test experiments for determining the patient’s blood group.

Explore : Blood Group Test

Other important functions of blood plasma are:

Along with other nutrients, blood plasma also contains important proteins and other essential components necessary for overall health. Hence, blood plasma transfusions are given to patients with liver failure and life-threatening injuries.

Plasma is the fluid particles of the blood, which contains the clotting agent fibrinogen, and functions by preventing the excessive flow of blood during injury.

Blood plasma proteins help in the transportation of glucose and other nutrients to different parts of the body.

Plasma in the blood helps in the regulation of body temperature and is also responsible for controlling blood pressure.

Plasma is referred to as the matrix of blood. It is composed of clotting factors, protein compounds and serum. It comprises 92 per cent water with proteins, salts, lipids and glucose. Plasma is the main medium for excretory product transportation.

Other than the blood clotting, this fluid matrix also functions by circulating both red blood cells and white blood cells, hormones, blood platelets and other digested food particles.

As mentioned above, plasma also functions as the main medium for excretory product transportation by carrying away waste materials from the cells to the excretory organs where it is flushed out of the body.

Refer more: MCQs on Excretory Products And Their Elimination

This article concludes with an introduction to blood plasma. To know more about blood plasma, its features, functions, important facts and other related topics, keep visiting our website at BYJU’S Biology.

Frequently Asked Questions

Define plasma proteins.

Plasma proteins are defined as proteins present in the blood plasma. They perform a variety of tasks, such as transporting hormones, lipids, vitamins and minerals for immune system functioning.

What are the functions of the 3 major plasma proteins?

Albumins play an important role in the regulation of osmotic pressure in the blood. Fibrinogens are the major components involved in the blood clotting process. The globulin proteins participate in immune responses as immunoglobulins.

What is plasma?

Plasma means an extracellular liquid portion of blood, which is transparent and pale yellow or straw-coloured. It is mainly composed of clotting factors and other protein molecules.

What is the percentage of plasma in blood?

Plasma is the straw-coloured thick fluid matrix of blood. About 55 percentage of blood volume is plasma and the remaining is made of blood cells.

What per cent of blood plasma is made up of proteins?

Blood plasma contains water, salts, proteins and dissolved minerals. Around 90-92% of plasma is water. The remaining 6-8% of plasma, consists of proteins such as albumins, globulins and fibrinogen.

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