Key Components and Vital Roles of Plasma in the Human Body
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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Albumin
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
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.
FAQs on Plasma in Biology: Definition, Structure & Functions
1. What is blood plasma and what is it composed of?
Blood plasma is the yellowish, liquid component of blood that holds the blood cells in suspension. It constitutes about 55% of the total blood volume. The main components of plasma are:
- Water: Makes up about 90-92% of plasma volume and acts as a solvent.
- Plasma Proteins: Constitute 6-8% and include albumin, globulins, and fibrinogen.
- Other Solutes: Includes electrolytes (like sodium, potassium, calcium), nutrients (glucose, amino acids), hormones, and waste products (urea, creatinine).
2. What are the main functions of plasma in the human body?
Plasma performs several critical functions for the body's survival and regulation. Its primary roles are:
- Transport: It carries blood cells, nutrients, hormones, and proteins to various parts of the body and transports waste products away from cells to the kidneys and liver for excretion.
- Regulation: Plasma helps maintain a stable body temperature by absorbing and distributing heat, and it contains buffers that regulate the blood's pH level.
- Protection: It contains clotting factors like fibrinogen to prevent excessive bleeding and antibodies (immunoglobulins) to fight infections.
- Maintaining Blood Pressure: The volume of plasma is crucial for maintaining blood pressure and circulation throughout the body.
3. What are the different types of proteins in plasma and their roles?
Plasma contains three main types of proteins, each with specific functions:
- Albumin: This is the most abundant plasma protein. Its main function is to maintain the colloid osmotic pressure of the blood, which helps to keep fluid within the blood vessels.
- Globulins: This group includes alpha, beta, and gamma globulins. Gamma globulins, also known as antibodies or immunoglobulins, are essential for the immune response. Alpha and beta globulins transport lipids and metal ions.
- Fibrinogen: This is a crucial protein for blood coagulation. During injury, it is converted into fibrin to form a stable blood clot.
4. How is serum different from plasma, and why is this distinction important?
The key difference between serum and plasma lies in the presence of clotting factors. Plasma is the complete liquid part of blood, containing all proteins, including fibrinogen and other coagulation factors. In contrast, serum is the fluid that remains after the blood has been allowed to clot and the clot has been removed. Therefore, serum is essentially plasma minus the clotting factors. This distinction is vital in medical diagnostics, as many blood tests require serum to prevent the sample from clotting, which would interfere with the analysis.
5. Is the 'plasma' in our blood the same as the 'plasma' state of matter studied in physics?
No, they are fundamentally different concepts that happen to share the same name. Blood plasma is the liquid matrix of blood, primarily composed of water, proteins, and dissolved substances. Plasma in physics refers to the fourth state of matter, where a gas is energised to the point that its atoms lose their electrons, creating a mixture of charged ions and electrons. So, while blood plasma is a liquid, physical plasma is a superheated, ionised gas found in stars and lightning.
6. How does plasma help maintain homeostasis in the body?
Plasma is central to maintaining homeostasis, the body's stable internal environment, through several mechanisms. It helps regulate body temperature by distributing heat. Its buffer systems, particularly the bicarbonate buffer system, maintain blood pH within a narrow range (7.35-7.45). Furthermore, plasma proteins, especially albumin, regulate osmotic pressure, controlling the exchange of water between the blood and the surrounding tissues, thus maintaining fluid balance and blood pressure.
7. Why can a severe lack of protein in the diet lead to swelling in the body (oedema)?
A severe lack of dietary protein can lead to a condition called oedema, or swelling, because of plasma's role in fluid balance. The liver produces plasma proteins, like albumin, from the amino acids obtained from our diet. Albumin is responsible for maintaining the colloid osmotic pressure, which pulls and holds fluid inside the blood vessels. If protein intake is too low, albumin levels in the plasma drop. This reduces the osmotic pressure, causing fluid to leak out of the capillaries and accumulate in the surrounding tissues, resulting in swelling, particularly in the abdomen and limbs.
