CHAPTER 1 HAEMOPOIESIS
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,Haematopoiesis 1
What is Haematopoiesis? 1
Types of Blood Cells 1
What is a Haemopoietic Stem Cell (HSC)? 2
Haematopoiesis Hierarchy 3
Core Concepts in Haematopoiesis 5
Sites of Haematopoiesis: Before and After Birth 6
Regulation of Haematopoiesis 7
Bone Marrow Microenvironment 8
Cell Adhesion Molecules (CAMs) 8
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Cytokines and Growth Factors 9
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What are CD Antigens? 10
Granulocytes: Quick Refresher 11
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CD Markers on Granulocytes 11
Clinical and Laboratory Use 12
Study Tip: 12
Cytokine Signaling es 14
What is EPO? 14
EPO Feedback Cycle (Negative Feedback Loop) 14
○ The cycle maintains homeostasis (a stable internal environment). 15
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Summary Table 15
Clinical Relevance 15
Overview of Erythropoiesis 16
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Summary 18
20 MCQs on Haematopoiesis 19
Essay Questions 23
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Q1: What happens when defective or insufficient levels of haemoglobin are
produced? 23
1. Reduced Oxygen-Carrying Capacity 23
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2. Impaired Red Blood Cell Production 23
3. Red Blood Cell Destruction (Haemolysis) 23
4. Microcytic, Hypochromic Anaemia 23
5. Increased Erythropoietin (EPO) Production 24
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Key Cytokines in Haemopoiesis 25
Key CAMs and Their Roles 26
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, PART 1 - HAEMATOLOGY
Haematopoiesis
What is Haematopoiesis?
● Haem = blood, Poiesis = production
● The process by which all blood cells are produced from pluripotent stem cells
● Generates:
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○ ~200 billion RBCs/day
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○ ~10 billion WBCs/day
○ ~400 billion platelets/day
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Types of Blood Cells
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Haematopoiesis gives rise to three major lineages of blood cells:
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Lineage Cell Types Function
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Erythroid Erythrocytes (RBCs) Oxygen transport
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Myeloid Neutrophils, Eosinophils, Basophils, Immune defense,
Monocytes, Platelets clotting
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Lymphoid B cells, T cells, NK cells Adaptive immunity
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