MEDI1000 Study Guide - Final Guide: Granulopoiesis, Yolk Sac, Hematology
16 Jun 2018
School
Department
Course
Professor
Introduction to Haematology
Haematology
-The study of blood
-But blood is also used in other disciplines
-Haematology includes
-Haemopoiesis
-Formed elements of blood
-Haemoglobin
-Coagulation
-Blood transfusion/cross matching
Haemopoiesis
-The production of the formed elements of blood - WBC’s, RBC’s and platelets
-Erythropoiesis - production of RBC’s
-Thrombopoiesis - production of platelets
-Granulopoiesis - production of granulocytes
-Lymphopoiesis - production of lymphocytes
-Monocytopoiesis - production of monocytes
-All cell lines are derived from a single precursor cell
-Stem cell differentiates into mature cells under the influence
of growth factors
Sites of Haemopoiesis in the Foetus
-Foetus
-yolk sac,
-liver
-spleen,
-bone marrow
-lymph nodes
-Adult
-bone marrow
Lineages of Blood Cells
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Formed Elements of Blood
Red Blood Cell (RBC)
-Most numerous type of cell in blood
-Anuclear - no nucleus
-Biconcave disc (side profile), “Area of central pallor”
-7.2 - 8.0 μm diameter
-Lifespan – 120 +/- 20 days
-Contain haemoglobin
-transports oxygen
-gives RBC’s a red colour
-Shape allows
-rapid diffusion of gasses
-flexibility
-change in shape/size
-Shape maintenance depends on
-energy
-membrane structure:
-lipid
-protein
-carbohydrate !
Platelets
-Second most numerous type of cell in blood
-Discoid (disc shaped)
-Anuclear
-3 μm diameter
-Small cytoplasmic fragments derived from large cells in the bone marrow called
megakaryocytes
-Primary role is the prevention of blood loss !
White Blood Cells
Granulocytes
Neutrophils
-Most common type of WBC
-10-12 μm diameter
-Multi-lobed nucleus
-Small granules in cytoplasm
-Polymorphonuclear cells
-Spend 8-10 hours in circulation
-Bacterial and fungal infections
Eosinophils
-Bi-lobed nucleus
-10-12μmdiameter
-Large, strongly staining (orange/red) cytoplasm granules
-Circulate for 4-5 hours
-Defence against parasitic infections
-Dampen allergic responses
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Basophils
-Least numerous circulating WBC’s
-Rarely seen when examining blood film
-8-10 μm diameter
-2-4 lobes in nucleus
-Large cytoplasmic granules (dark staining)
-Involved in the following reactions:
-hypersensitivity
-inflammatory
Agranulocytes
Lymphocytes
-Second most common WBC in peripheral blood
-10-12 μm indiameter
-Large round nucleus/less cytoplasm
-Variable lifespan: few days -years
-T-lymphocytes: cell-mediated immunity
-B-lymphocytes: humoral immunity
Monocytes
-Largest WBC (16 - 22 μm diameter)
-Kidney shaped nucleus
-Circulate for ~10hours
-Exit into tissues - become macrophages
-Removal of aged RBC’s and other debris
-Antigen processing
-Presentation to T lymphocytes
Abnormalities
Abnormal Cell Morphology
-Morphology refers to the “appearance” of a cell
-Abnormal cell morphology indicates:
-Change in cell structure/function
Abnormal RBC’s Morphology
Anisocytosis
-Change in Size of RBC’s
-Decreased size - Microcytosis
-Increased size - Macrocytosis
Poikilocytosis
-Change in shape of RBC’s
Elliptocytes:
-Thin elongated cigar shaped cells
-Change to membrane structure
-Found in various types of anaemia
Ovalocytes:
-Oval shaped rather than thin or round
-Less pronounced defects
-Found in some types of anaemia
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Document Summary
But blood is also used in other disciplines. The production of the formed elements of blood - wbc"s, rbc"s and platelets. All cell lines are derived from a single precursor cell. Stem cell differentiates into mature cells under the in uence of growth factors. Most numerous type of cell in blood. Biconcave disc (side pro le), area of central pallor . Second most numerous type of cell in blood. Small cytoplasmic fragments derived from large cells in the bone marrow called megakaryocytes. Primary role is the prevention of blood loss. Second most common wbc in peripheral blood. Largest wbc (16 - 22 m diameter) Removal of aged rbc"s and other debris. Morphology refers to the appearance of a cell. Oval shaped rather than thin or round. Found in conditions with trauma to rbc"s e. g. burns. Stretched out of shape - excessive time (spleen) Oval or rectangular area of central pallor. Acute blood loss, burns, uraemia - kidney failure.
