15.1.1. Plasma

Plasma is a straw-coloured, viscous fluid constituting nearly 55 per cent of the blood. 90-92 per cent of plasma is water and proteins contribute 6-8 per cent of it.

Plasma is the liquid component of blood, making up more than half of its volume. Most of plasma's content is water, which is crucial for various bodily functions, such as transporting nutrients, hormones, and waste products.

Think of plasma like the ocean in which fish (blood cells) swim; just as ocean water transports various substances needed by the fish and carries away waste, plasma helps transport essential nutrients and waste in the body.

Fibrinogen, globulins and albumins are the major proteins. Fibrinogens are needed for clotting or coagulation of blood. Globulins primarily are involved in defense mechanisms of the body and the albumins help in osmotic balance.

Plasma contains various types of proteins that serve different functions. Fibrinogen is essential for blood clotting, helping to stop bleeding when injuries occur. Globulins play a role in immune response, defending the body against pathogens, while albumins maintain osmotic pressure, which helps regulate fluid balance in the blood and tissues.

Imagine the role of a city’s emergency services: Fibrinogen is like firefighters, quickly responding to prevent blood loss; globulins are like police and medical teams that protect the city (your body) by fighting off invaders, while albumins act like city planners ensuring proper resource distribution.

Plasma also contains small amounts of minerals like Na+, Ca++, Mg++, HCO–, Cl–, etc. Glucose, amino acids, lipids, etc., are also present in the plasma as they are always in transit in the body.

In addition to proteins, plasma carries important minerals and nutrients essential for bodily functions. These include electrolytes like sodium and calcium, which help maintain nerve function and muscle contractions. Glucose and amino acids are vital for energy production and building proteins, respectively, showing how plasma is essential for ongoing metabolic processes.

Think of plasma as a delivery truck, transporting all sorts of essential supplies (nutrients and minerals) to different parts of the city (your body). Just as a truck must carry ingredients to a factory to produce goods, plasma delivers nutrients and electrolytes to cells for growth and energy.

Factors for coagulation or clotting of blood are also present in the plasma in an inactive form. Plasma without the clotting factors is called serum.

Plasma contains several factors necessary for blood coagulation, which function only when activated, typically during injury. If the plasma is separated from these clotting factors during the blood collection process, what remains is referred to as serum, which lacks the ability to clot.

Consider a safety net that is only deployed in emergencies; the clotting factors in plasma are like the net that’s folded until needed. When an injury happens, the net unfolds (the factors activate) to prevent a fall (blood loss). Without it, it's just an empty space (serum).

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