Blood Coagulation and Disorders

Introduction

You know that blood is the river of life that surges within us, transporting nearly everything that must be carried from one place to another within the body. normally, blood flows smoothly past the intact lining of the body for the stoppage of bleeding, called as hemostasis. the homeostasis response is quick, localized, and thoroughly regulated. it involve many blood coagulation factors typically present in blood plasma, and some substances released by the platelets and injured tissue cells. disorder that affect the blood are called hematologic disorder influence either the quantity as well as the function of blood cells or proteins in the blood clotting system affecting process of coagulation. in this unit, we will have a detailed look at the composition and functions of this life-supporting fluid (blood) that serves as a transport vehicle in the body. the mechanism of blood coagulation and various sorts of blood- related disorders will also be examined in detail.

Expected learning outcomes

After studying this unit, you should be able to:

1. Explain various composition of the blood;

2. Describes the three mechanisms that contribute to hemostasis;

3. list the steps of blood clotting and explain the various factors that affect the process; and

4. understand disorders or diseases associated with the blood.

Composition of blood

Blood is a fluid connective tissue that flows in the human body and transports various substances. it consists of two components; blood cells also called as formed elements and the plasma, which is a non- living and proteins-rich fluids matrix in which the cellular components are suspended. the formed cells are of three kinds;- white blood cells, red blood cells and the platelets. if a blood sample is centrifuged, the heavier cells are packed  down by the centrifugal force while the less dense plasma stays at the top.

the majority of the reddish mass at the bottom of the tube comprises red blood cells (erythrocytes). a thin whitish layer called the buffy coat containing white blood cells (leucocytes) and platelets is present at the erythrocyte-plasma intersection.

 Erythrocytes typically comprise about 45% of the absolute volume of a blood sample, a percentage known as the "hematocrit". leucocytes and platelets contribute less than 1% of blood volume. plasma makes up a larger 55% portion of the whole blood.

The process by which the formed elements of blood develop is called hemopoiesis or hematopoiesis. in an embryo, the process occurs in the liver, spleen, thymus, and lymph nodes of a fetus. red bone marrow turns into the essential site of hemopoiesis is in the last three months of the gestation periods, and proceeds as the source of blood cells after birth and all through life. the bone marrow cells capable of producing all cellular elements of the blood are known as Hematopoietic stem cells (HSCs). the formation and development of blood cells in organs(liver, spleen thymus, and lymph nodes) external to the bone marrow medullary spaces is termed extramedullary hematopoiesis (EMH)