Tabuk University Tabuk University Faculty of Applied Medical Sciences Department Of Medical Lab. Technology 2 nd Year – Level 4 – AY

Erythrocyte, Haemoglobin and Introduction to Anaemias Mr. Waggas Elaas, M.Sc, MLT

Objectives 1. To know detailed information about erythrocytes. 2. To know the synthesis, structure and function of Hemoglobin. 3. To identify anemias and know their classification. 3

An Erythrocyte (RBC) Biconcave discs Non nucleated 120 days life span Practical Values 65% of Fe in Hb 1 g Hb = 3.46 mg Fe 1 mL blood at 15 g/dL Hb = 0.5 mg Fe Normal Values RBCs, male x 10 6 /µL female x 10 6 /µL Hb, male g/dL female g/dL 4

RBCs structure: Three Constituents of RBCs: RBC membrane + internal metabolic apparatus + hemoglobin RBC membrane: Has lipid bilayer membrane with proteins in it. Below this membrane there is a cytoskeleton of proteins allowing rubbery elasticity with main protein being Spectrin & Ankyrin Membrane antigen structure – there are over 300 RBC membrane Ags. They are Polysaccharides. (Blood Groups A, B, Rh, Duffy, etc). 5

The red cell membrane 6

Red cell metabolism Embden-Meyerhof Pathway - glycolysis from glucose to lactate. ATP is produced. Hexose-Monophosphate Shunt (Pentose phosphate Pathway) - 10% of glycolysis. NADPH is generated and used to protect Hb and membrane from oxidation. Methemoglobin Reductase Pathway - prevents iron of Hb from being oxidized, makes NADH which is reducing power. 7

The main function of red cells is to carry O 2 to the tissues and to return carbon dioxide (CO 2 ) from tissues to the lungs. In order to achieve this; the red cells contain the specialized protein hemoglobin. Each red cell contains approximately 640 million Hb molecules. 8 How erythrocytes carry O 2 & CO 2 ?

65% of the Hb is synthesized in the erythroblasts, and 35% at the reticulocyte stage. Although haem and globin synthesis occur separately within developing red cell precursors, their rates of synthesis are carefully coordinated to ensure optimal efficiency of Hb assembly. 9

Haemoglobin The haemoglobins are red globular proteins, which have a molecular weight of about 68,000 and comprise almost one third of the weight of a red cell. 10

Hb structure Each RBC contains 640 million Hb molecule. Each molecule consists of 4 Polypeptide chains. Polypeptide amino acids Each polypeptide chain has a Haem group Haem & Globin بروتين حديد How many Haem groups in each Hb molecules??? 11

Haem synthesis - In the developing erythroblasts. - By Mitochondria - Biochemical reactions : Glycine + Succinyl Coenzyme –A  -ALA Protoporphyrin vit. B 6 Protoporphyrin + Fe 2+ Haem 12

Globin synthesis - In the developing Erythroblasts. - By ribosomes. - Each molecule of normal adult haemoglobin (Hb-A) consists of four polypeptide chains    , each with its own haem group - Each globin chain is a polypeptide of approximately 150 amino acids in length 13

Hb synthesis 14

Hb structure Hb structure 15

Haemoglobin Normal adult blood also contains small quantities of two other haemoglobins: Hb-F Hb-A 2 These also contain  chains but with  and d chains respectively instead of . The major switch from fetal to adult haemoglobin occurs 3-6 months after birth. Why the fetus has a different Hb.??? 16

Normal Hb in adult blood Hb A Hb A 2 Hb F structure 22222222 2d22d22d22d2 22222222 Normal % % % % 17

Introduction to Anaemias Anemia is defined as a reduction in Hb concentration. Less than 13.5 g/dl males Less than 11.5 g/dl female Less than 14.0 g/dl neonate Less than 11.0 g/dl from 2 yrs – puberty 18

Plasma volume alterations affect Hb conc. Increase in plasma volume (splenomegally & pregnancy) may cause anemia even with normal Hb conc. And red cell count. Decrease in plasma volume (dehydration) may mask anemia. 19

Clinical Features Fatigue. إعياء headache. صداع Faintness. الضعف Dyspnea. ضيق في التنفس Angina. نوبات قلبية Palpitations. خفقان Tachycardia. تسارع القلب murmur. صوت وأزيز 20

Signs 1- General Pallor of mucus membranes (Hb less than 10 – 9 g/dl) Tachycardia 21

Signs 2- Specific Koilonychia (spoon nails in iron deficiency) Jaundice in Hemolytic anemias Leg ulcers in sickle cell disease. Bone deformities in Thalassemia. 22

Causes 1. Reduced red cell production. 2. Increased red cell destruction. 3. Blood loss. 23

According to MCV)) Classification of anemia According to MCV)) Classification of anemia Normocytic normochromic anemia ◦ Some anemias of chronic disease ◦ hemolytic anemias (accelerated destruction of RBCs) ◦ anemia of acute hemorrhage – blood loss ◦ aplastic anemias & Bone marrow failure ◦ Renal disease. ◦ MCV : Mean Cell Volume 24

Microcytic Hypochromic, anemia ◦ iron deficiency anemia ◦ thalassemias ◦ anemia of chronic disease (rare cases) ◦ Sideroblastic anemia ◦ Lead poisoning 25

Macrocytic anemia ◦ Megaloblastic anemia (vitamin B12 or Folate deficiency) ◦ Alcohol ◦ Liver disease ◦ Myeldysplasia ◦ A plastic anemia 26

Homework What should you do to avoid having anemia? Why is oxygen important to blood and to the cells? Mature erythrocytes: A) have a centrally located nucleus. B) are actually just cellular fragments. C) contain hemoglobin in their cytoplasm. D) mature from cells called megakaryocytes. E ) do not contain protein 4. Plasma is: a) blood that has no red blood cells b) the liquid portion of blood including clotting factors c) the liquid portion of blood after it has clotted d) the proteins of blood 27

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