Plasma Components
பிளாஸ்மா கூறுகள்
Stop confusing blood with plasma. Plasma is the matrix, not the cells. If you miss the 55% volume statistic, you are losing easy marks in the first section of the paper.
The idea
Plasma is a straw-coloured, viscous fluid that makes up 55% of blood. It consists of 90-92% water and 6-8% proteins. The primary proteins are fibrinogen, globulins, and albumins. It also transports essential nutrients like glucose, amino acids, and lipids.
Why it matters
It acts as the transport medium for dissolved nutrients, hormones, and proteins, while maintaining osmotic balance and blood clotting potential.
NEET lens
NEET focuses on the percentage values of water and proteins. Memorize the specific functions of fibrinogen (clotting), globulins (defense), and albumins (osmotic balance). Do not confuse these with serum, which is plasma without clotting factors. Expect a direct 'match the following' or 'incorrect statement' question.
Clinical significance
Fibrinogen is essential for blood clotting. A deficiency leads to prolonged bleeding disorders. Albumin maintains osmotic pressure; its reduction causes edema, where fluid leaks into tissues.
Introduction
Blood plasma is the straw-colored liquid matrix of blood (55% of blood volume), composed of ~90-92% water and dissolved proteins, electrolytes, nutrients, hormones, gases, and waste products.
Core concept
Composition: Water: 90-92%. Proteins (7-8%): Albumin (most abundant, 60%) — maintains oncotic pressure, transports fatty acids/drugs. Globulins — immune function (immunoglobulins), transport (transferrin, ceruloplasmin). Fibrinogen — clotting. Prothrombin — clotting. Electrolytes: Na⁺ (most abundant cation), Cl⁻ (most abundant anion), K⁺, Ca²⁺, Mg²⁺, HCO₃⁻. Nutrients: glucose, amino acids, lipids (as lipoproteins). Waste: urea, creatinine, uric acid. Hormones, vitamins, gases (dissolved O₂, CO₂, N₂). Serum = plasma minus clotting factors (fibrinogen, prothrombin) — what remains after blood clots.
Go deeper
Oncotic pressure (colloid osmotic pressure): plasma proteins (mainly albumin) create osmotic pressure that draws water back from tissues into capillaries. If albumin is low (liver disease, malnutrition) → oncotic pressure falls → fluid stays in tissues → edema. This is why malnourished children have swollen bellies (kwashiorkor).
From Class 10
Blood is made of a liquid part and a cellular part. The liquid part — plasma — carries dissolved substances throughout the body.