Hematology 1: Haemopoiesis - Blood Composition & Functions

Hematology 1: Haemopoiesis
Dr. DIA MOUNDO Christian Franck
M.D., General practitionner
Level 2 Nursing and Biomedical sciences

CHAPTER ONE : BLOOD
Learning Objectives
At the end of this chapter, the student shall be able to:
• Explain the composition of blood
• Describe the function of blood

1. Composition blood
Blood is a circulating tissue composed of fluid plasma and cells.
It is composed of different kinds of cells (occasionally called
corpuscles); these formed elements of the blood constitute about
45%of whole blood.
The other 55%is blood plasma, a fluid that is the blood's liquid
medium, appearing yellow in color.
The normal pH of human arterial blood is approximately 7.40 (normal
range is 7.35-7.45), a weak alkaline solution.

1. Composition blood
Blood is about 7% of the human body weight, so the average adult
has a blood volume of about 5 liters, of which 2.7-3 liters is plasma.
The combined surface area of all the red cells in the human body
would be roughly 2000 times as great as the body's exterior surface.

1. Composition blood
1.1. Blood plasma
When the formed elements are removed from blood, a straw-colored
liquid called plasma is left.
Plasma is about 91.5% water and 8.5% solutes, most of which by
weight (7%) are proteins..
Some of the proteins in plasma are also found elsewhere in the body,
but those confined to blood are called plasma proteins.
These proteins play a role in maintaining proper blood osmotic
pressure, which is important in total body fluid balance.