Dhristi NEET 2022-24

What is Plasma?

Plasma is defined as the component of the blood which remains after removing the blood cells from the blood. There are WBC, RBC and platelets, these cells float in the medium which is defined as plasma. The blood plasma accounts for around 55% of the body's total blood volume. It's the extracellular fluid's ventricular component. The blood plasma is primarily constituted of water 95 per cent by volume with essential dissolved proteins that constitute up to 6 to 8 per cent. Apart from proteins, glucose, clotting factors, electrolytes are the constituents of the blood plasma. 

The article deals with what is plasma, the constituents of plasma and the functions of blood plasma. The article also answers questions like what is plasma donation and what is plasma used for.

Molecular Components of Plasma

As described earlier what is plasma, it is an aqueous solution made up of 90% water, 8% soluble blood plasma proteins, 1% electrolytes, and 1% constituents in transportation. Salt makes up 1% of plasma, which aids in pH regulation. The typical volume of human blood plasma is 2.7–3.0 litres. Since plasma is responsible for the transport of molecules throughout the body, respiratory gases like oxygen and carbon dioxide can dissolve in the plasma directly. The majority of oxygen is coupled to haemoglobin, while the majority of carbon dioxide is converted to bicarbonate ions in the plasma. The plasma also contains hormones and nutrients such as glucose, amino acids and proteins, lipids and fatty acids, and vitamins. Urea and ammonia are among the waste products conveyed via the plasma during elimination. Three key proteins make up the greatest group of solutes in plasma: albumins, globulins, and clotting proteins. It is the dissolved proteins (immunoglobulins) because of which plasma donations are done to patients lacking the particular immunoglobulins (antibody).  Let us briefly look into each of the proteins that are key components of the blood plasma.

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About two-thirds of the proteins in plasma are albumins, which are synthesized inside the liver. Albumins are responsible for maintaining the osmotic equilibrium in the bloodstream. Oncotic or osmotic pressure is a force exerted by these proteins that results in the incoming of water into the fluid. Albumins exit the vascular endothelium and enter the tissues amid inflammation, transporting water and some plasma into the interstitial fluid. This drains into the lymphatic system, which then redistributes it again further into the circulatory system's plasma. Exudate oedema, or swelling that signals inflammation, is caused mostly by albumin. Due to the force imposed by their oncotic pressure, albumins also aid in the movement of other items, such as vitamins and specific compounds and drugs. Some of the compounds whose transportation is mediated by albumin include bilirubin, fatty acids, and penicillin. 


Globulins are a broad set of proteins classified into three classes based on how far they migrate throughout electrophoresis assessments. The three categories of protein include gamma, alpha, and beta. The primary role of blood plasma globulin is to carry different chemicals through the bloodstream. For example, the beta globulin named transferrin is involved in iron transportation. Beta globulins are commonly used as enzymes in the body. Alpha globulins are known for their ability to block particular proteases. A major class of gamma globulin is the antibodies (also known as immunoglobulins), which help the immune system fight against infections and sickness. In passive immunity, these immunoglobulins are transferred from the blood plasma to an acceptor; the process is known as plasma donation.

Clotting Factors

The liver is the primary producer of clotting proteins. After endothelial damage, the cascade clotting process which involves twelve proteins known as clotting factors gets activated. Fibrinogen is one of the key clotting factors. When fibrinogen is stimulated by the coagulant thrombin, it gets converted into an active form called fibrin. Fibrin forms a lattice that clots blood with the help of a platelet plug. Blood also contains anticoagulants.  Anticoagulants and fibrinolytic in the blood, such as plasmin and heparin are responsible for disintegrating fibrin clots and rendering thrombin inactive. Damaged cells, on the other hand, produce tissue factor, another type of clotting factor that triggers a cascade of thrombin generation, overpowering the anticoagulants and causing a clot.

What is Plasma Donation?

Since we have understood facts about plasma, like, what is plasma, constituents of plasma in the human body. Let us answer the question of what is plasma donation? Humans lose a huge amount of plasma if they lose a great deal of blood, which commonly happens as a result of a traumatic injury or surgery. Considering plasma's many roles, this might have major consequences for anyone's health. This is why, in addition to whole blood, organisations collect plasma. This is known as plasma donation. Plasma is usually frozen fresh (FFP) or frozen within 24 hours of phlebotomy.

Plasma can be given in two ways. The first is through whole blood donation. The blood components, including plasma, are then separated in laboratories when required. The alternative option is to donate solely plasma. Plasmapheresis is the procedure used to accomplish this. Blood is drawn from the vein into a centrifuge by a machine. A centrifuge is equipment that differentiates plasma from other blood and its components by spinning vigorously. Due to the fact that plasma is naturally lighter than many other components, it rises to the top during the process. The equipment will store the plasma and deliver other components back into your body, such as red blood cells.

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In conclusion of the article, we have seen facts about plasma, what is plasma donation is, the components of the blood plasma. We have also seen what is plasma used for.

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FAQs (Frequently Asked Questions)

1. What is the function of plasma?

The elimination of waste from cellular operations that assist to create energy is one of the plasma's key tasks. Plasma absorbs and transfers waste to other parts of the body for elimination, such as the kidneys and liver. Plasma also aids in the regulation of body temperature by absorbing and releasing heat as required. Plasma has numerous more important activities in addition to carrying waste and controlling body temperature like marinating the osmotic balance of the extracellular fluid, maintaining the pH of the blood.

2. What is serum?

The term "serum" refers to plasma that has been stripped of its clotting components. As a consequence, serum still includes albumin and globulins, which are referred to as serum proteins. All electrolytes, antibodies, antigens, hormones, and other foreign compounds are found in serum and are not employed in blood clotting. White blood cells (leukocytes), red blood cells (erythrocytes), platelets, and clotting factors are not found in serum. In the blood, human serum serves as a circulatory transporter of endogenous and exogenous liquids. It permits materials to adhere to the serum's molecules and become buried inside them. As a result, human serum aids in the transfer of fatty acids and thyroid hormones.