Blood Lecture




  • Is the transport system of the body.
  • it is the means through which nutrients and oxygen are taken to the cells and waste products are removed from the body.
  • Every cell in the body depends on blood for its nourishment. Therefore any disorder of blood affects the whole body.


Consists mainly of:

1. liquid part (plasma) 55%

2. cells: 45%

  • red blood cells or erythrocytes
  • white blood cells or leukocytes
  • platelets or thrombocytes


Function of blood (Cell and Plasma)

  • Brings nutrients, oxygen, hormones, and enzymes to the cells.
  • Removes waste products from tissues.
  • Takes part in regulating fluid volume, electrolyte distribution and body temperature.
  • Protects body against harmful agents.

– Blood is the only fluid tissue in the body. Blood transports oxygen and nutrients to body tissues, and removes waste and carbon dioxide. Blood distributes nearly everything that is carried from one area in the body to another place within the body. For instance, hormones are transported from the endocrine organs to their target organs. Blood helps maintain body temperature and normal pH levels in body tissues. The protective functions of blood include clot formation and the prevention of infection.


Functions of Blood Cells

Red Blood Cell RBC

  • Contains Hb which carries O2 to the cells and CO2 away from the cell
  • Live for about 90-120days

White Blood Cells WBCs


  • Protect body from infection
  • 2 types of cells:
  • Granulocytes
  • Agranulocytes


  • Neutrophils: 50% -70% phagocytosis
  • Eosinophils:1% – 5 detoxify proteins
  • Basophils:1% release histamines in response to allergies, prevent clotting in small blood vessels.
  • Agranulocytes – Lymphocytes 25%
  • B-cells: synthesize antibodies.
  • T-cells: killer cells, Help B-cells destroy foreign proteins
  • Monocytes: phagocytosis in tissue.



  • Prevent bleeding; help in clotting; live for 10 days.
  • Transports molecules.
  • Contains protein that keep fluid in blood vessels (osmotic pressure).
  • Contains fibrinogen for clotting.
  • Contains gamma globulins antibodies to fight foreign substances.

– Anemia is a condition in which the oxygen carrying ability of the red blood cells is inadequate or lack of hemoglobin to meet the demands of the tissue for oxygen.

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