This document discusses hematology, which is the study of blood. It describes the components of blood, including red blood cells, white blood cells, platelets, and plasma. Blood functions to transport gases, nutrients, waste products, and hormones throughout the body, and helps with defense, homeostasis, and hemostasis. The document also examines hematopoiesis, the process of blood cell formation, and the roles of the bone marrow, hormones, nutrients like iron and vitamins in supporting normal red blood cell production.

1. By:
Dr: Samraa Abd alwhab Khider

2.  Hematology (Greek Haema = Blood; logy = Study
of).
 Hematology is the branch of medical science that
deals with the study of blood.
 Blood, along with the cardiovascular system
constitutes the Circulatory system .

3.  Blood is a type of connective tissues.
 It consist of :
1- Cells (cellular part).
2- plasma (fluid part ).
 The cells are:
 Red blood cells (RBCs) or erythrocytes.
 White blood cells (WBCs) or leukocytes.
 Platelets or thrombocytes.

5.  Volume of blood is about 5 litters in an average
adult male.
 8% of the total body weight.
 Volume of plasma is about 3.5 L (5% of total body
weight)

6.  The cells in the blood can be separated by
centrifugation.
 The percentage of cells in blood is called the packed
cell volume (PCV) or the hematocrit.
 Most of these cells are RBCs (99.9%).

7.  Normal values : - male 40-50%
- Females 37-47%
 Low PCV indicate anemia.
 High PCV indicates polycythemia.

10. 1-Transport of :
 Gases (e.g. oxygen & carbon dioxide).
 Nutrients (e.g. glucose, amino acids & free fatty
acids ).
 Waste products (e.g. urea & uric acid).
 Hormones (e.g. insulin & cortisol).
2- Defense by WBCs and antibodies .

11. 3- Homeostasis:
 Maintains constant internal environment( e.g.
temp., PH ).
4- Hemostasis:
 Prevention of blood loss & maintenance of blood in
fluid state.

12. Definition :-
 Hematopoeisis: mechanism of blood cells formation
& stages of development.
 Include:
1- Erythropoiesis: formation of RBCs.
2- Leukopoiesis: formation of WBCs.
3- Thrormbopoiesis: formation of platelets.

13. 1-Fetal period :
 First trimester: yolk sac.
 Second trimester: liver & spleen.
 Third trimester: red bone marrow.
2- After birth:
 Red bone marrow of all bones at first.
 Then the active red bone marrow becomes
gradually replaced by inactive yellow marrow.

14. 3- The sites during adult :-
 At about age of 20y the red marrow is confined to:
 The flat bones (skull, scapula, ribs, sternum,
vertebrae & iliac bone ).
 The end of long bones.
 Small bones of the hand & feet.

16.  Normal erythropoiesis requires:
1- Normal bone marrow.
2- Certain hormones (erythropoietin).
3- Nutrients(e.g. iron, folic acid, and vitamins).
4- Certain cytokines and growth

17.  Amino acid:
 For formation of globin in hemoglobin.
 Iron:
 For formation of heme in Hb.
 Deficiency causes microcytic hypochromic anemia.

18.  Folic acid:
 For DNA synthesis.
 Deficiency causes macrocytic normochromic
anemia.
 VitaminB12:
 For DNA synthesis
 Deficiency causes macrocytic normochromic
anemia.