Blood Plasma

Roughly 92% water, mixed with organic and inorganic substances
The most abundant plasma solute is the plasma protein, of which there are three groups : albumins, globulins, and fibrinogen

Albumins : ~60% of the plasma proteins are albumins; they are the smallest of the proteins. They help to maintain osmotic pressure in the blood.
Globulins : ~36% of the plasma proteins. Alpha and beta globulins are, like albumins, made in the liver. They transport lipids and fat-soluble vitamins, among other things. Gamma-globulins are made in the lymphatic system, and they include antibodies.
Fibrinogen : ~4% of the plasma proteins; works in the blood clotting mechanism. It is the largest of the plasma proteins and is made in the liver.
A decrease in the number of plasma proteins can lead to a change in the osmotic pressure, resulting in edema.

Plasma also contains plasma nutrients (such as amino acids, simple sugars and lipids) and the blood gases (O₂ and CO₂)
Non-protein nitrogenous substances are also found in the plasma.

Urea, uric acid and amino acids fall into this category. The kidneys keep the levels of these substances low by constantly removing them.

Plasma electrolytes include Na⁺, K⁺, Ca²⁺, Mg⁺, Cl^- , HCO₃^-, PO₄^-, SO₄ . They work in maintaining osmotic pressure and blood pH, among being essential for many metabolic processes.

Hemostasis

How to stop bleeding? Several actions may occur when a vessel is ruptured.
Blood Vessel Spasm : the smooth muscle wall of the vessel contracts, constricting the vessel and minimizing blood loss.
Platelet Plug Formation : platelets adhere to the collagen that is found outside the vessel, then they adhere to themselves, forming a "cork" in the hole.
Coagulation : also called blood clotting

In the presence of Ca²⁺, prothrombin (an alpha-globulin) is converted to thrombin. (this is at the end of a long positive feedback cascade of reactions, started when the damaged vessel secretes cytokines)
Thrombin acts like an enzyme, causing fibrinogen molecules to join and become fibrin .
Fibrin will stick to the exposed surfaces of the broken vessel, creating a mesh or net to "catch" more platelets and other blood cells.
The mass which forms is called a blood clot.
A thrombus is a blood clot that forms abnormally. If it dislodges and is running through the system, it is called an embolus.
Hemophilia is a genetic disorder of the clotting mechanism. There are several types, indicating different clotting factors that are missing.

A transfusion of unknown blood runs the risk of causing agglutination , or a clumping of erythrocytes. It occurs due to the presence of counteracting agglutinogens and agglutinins.
ABO blood groups are based on the presence or absence of agglutinogen A and agglutinogen B.
Rh blood groups are based on several Rh agglutinogens, but the most important one is agglutinogen D.
Erythroblastosis fetalis arises from an Rh factor reaction between a mother and her unborn child