Plasma makes : March 2009
**Core Concept**
Plasma makes up approximately 55% of human blood volume and is the liquid component that carries cells, proteins, and other substances throughout the body. The production of plasma involves the filtration of blood through the glomeruli in the kidneys and the liver's role in protein synthesis.
**Why the Correct Answer is Right**
The correct answer is fibrinogen, a glycoprotein synthesized by the liver and secreted into the bloodstream. Fibrinogen is a crucial protein that plays a vital role in blood clotting. When tissue damage occurs, thrombin converts fibrinogen into fibrin, which forms a clot to stop bleeding. This process is essential for maintaining hemostasis and preventing excessive blood loss.
**Why Each Wrong Option is Incorrect**
* **Option A:** While albumin is a major plasma protein, it is not directly involved in blood clotting.
* **Option B:** Globulins are a class of plasma proteins, but they are not the primary component produced by plasma.
* **Option C:** Lipoproteins are involved in lipid transport, but they are not the primary component produced by plasma.
**Clinical Pearl / High-Yield Fact**
A key aspect of plasma function is its ability to transport clotting factors, including fibrinogen, to sites of injury. This process highlights the importance of plasma in maintaining blood homeostasis and preventing excessive bleeding.
**Correct Answer:** D. Fibrinogen