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ERYTHROCYTES AND HEMOGLOBIN

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  PART A: ERYTHROCYTES 4.1 Definition of Erythrocytes Erythrocytes , commonly known as red blood cells (RBCs), are specialized blood cells responsible primarily for transporting oxygen from the lungs to body tissues and participating in carbon dioxide transport from tissues to the lungs. Mature human erythrocytes have a distinctive biconcave disc shape. They lack a nucleus and most intracellular organelles, providing more space for hemoglobin and enabling considerable cellular deformability. General characteristics of mature erythrocytes Characteristic Description Shape Biconcave disc Diameter Approximately 7–8 µm Thickness Approximately 2–2.5 µm at the periphery and about 1 µm centrally Nucleus Absent Mitochondria Absent Main intracellular protein Hemoglobin Energy production Primarily anaerobic glycolysis Average lifespan Approximately 120 days Main site of production Red bone marrow Main site of removal Macrophages in the spleen, liver, and bone marrow Why are erythrocytes bicon...
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HEMATOPOIESIS

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3.1 Introduction to Hematopoiesis Hematopoiesis is the continuous physiological process through which all blood cells are produced, developed, matured, and released into the circulation. The major mature blood-cell populations produced by hematopoiesis are:  Erythrocytes (RBCs),  Leukocytes (WBCs), and  Platelets Although mature blood cells perform very different functions, they originate from a common population of hematopoietic stem cells (HSCs) . 3.2 Hematopoietic Stem Cells Definition A hematopoietic stem cell (HSC) is an immature blood-forming cell capable of: Self-renewal Differentiation into multiple blood-cell lineages Self-renewal Self-renewal allows the stem-cell population to maintain itself throughout life. Differentiation Differentiation is the process through which an immature stem/progenitor cell becomes progressively specialized. For example: HSC ↓ Myeloid progenitor ↓ Erythroid progenitor ↓ Erythroblast ↓ Reticulocyte ↓ Mature RBC 3.3 Origin and De...
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SPECIMEN COLLECTION

1.1 Introduction to Specimen Collection Specimen collection is the first major step in the laboratory testing process . The quality of the laboratory result depends not only on the analytical method but also on the quality of the specimen submitted for examination. The laboratory testing process can broadly be divided into: Pre-analytical phase → Analytical phase → Post-analytical phase Specimen collection is part of the pre-analytical phase . Pre-analytical phase includes: Patient identification Test/request verification Patient preparation Selection of appropriate specimen Specimen collection Correct container and anticoagulant Labeling Handling Transportation Storage/preservation An incorrectly collected or poorly handled specimen can produce an inaccurate result even when the laboratory instrument and analytical procedure are functioning correctly. 1.2 General Principles of Blood Collection Blood collection must be performed carefully to: Obtain a representative specimen Prevent co...
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INTRODUCTION TO HEMATOLOGY

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 INTRODUCTION TO HEMATOLOGY 1.1 What is Hematology? Definition Hematology is the branch of biomedical science and laboratory medicine concerned with the study of blood, blood-forming tissues, blood cells, and disorders of the hematopoietic system . The term hematology is derived from: Haema = blood Logos/Logia = study Thus, hematology literally means the study of blood . However, modern hematology is much broader than the study of blood itself. It includes the study of: Blood cells Plasma Bone marrow Blood cell formation Blood cell maturation Hemostasis and coagulation Blood cell disorders Hematological malignancies Laboratory investigation of hematological diseases 1.2 Scope of Hematology Hematology can be considered from two major perspectives: A. Normal Hematology The study of: Normal blood composition Normal blood cell structure Normal blood cell functions Blood cell production Blood cell maturation Normal physiological variation B. Clinical Hematology The study of: Disorder...
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