Week 10 Haematological System Flashcards
Haematopoeisis and Haemopoesis
Interchangeable terms —> describes formation of blood cells
Myelopoiesis
Formation of blood cells in the myeloid line (e.g., granulocytes, monocytes, erythrocytes, and platelets).
Lymphopoiesis
Formation of blood cells in the lymphoid cell line (e.g., B cells, T cells, and natural killer (NK) cells.
Haematopoietic stem cells (HSCs)
• The precursor cell to blood cells and begin the differentiation process.
• They are self-renewing and can make any blood cell in the body, (e.g., erythrocyte, B cell, T cell, etc.).
• They can also make other non-haematopoietic cells, when required, and are hence classed as pluripotent.
• HSCs are found predominately in the bone marrow in adults.
Haematopoietic Stem Cells vs Progenitor cells
BOTH
- Located in bone marrow
Heamatopoeitc Stem Cells
- High self renewal tendency
- Differentiate into progenitor cells
- Pluripotent
Progenitor Cells
- Limted self renewal tendency
- Differentiate into myeloid or lymphoid
- Multipotent
Site of haematopoiesis in an embryo
Yolk sac and then liver
Site of haematopoiesis in 3-7 month old foetus
Spleen
Site of haematopoiesis haematopoiesis in a 7-9 month old foetus
Begins to occur in bone marrow
Site of haematopoiesis between birth and maturity
Bone marrow and the tibia/femur
Site of haematopoiesis in adults
Bone marrow of the skull ribs and sternum
Types of WBCs
Neutrophils, Lymohocytes, monocytes eosinophil, basophil
Primary lymphoid organs
Where lymphocytes undergo ontogeny (get made and develop in mature B and T cells)
Thymus and Bone Marrow
Naive lymphocytes
Precursor lymphocytes that differentiate into effector lymphocytes
CD4 T cell —> Helper T Cell
CD8 T cell —> Cytotxic T cell
B Cell —> Plasma cell
Primary lymphoid organs
Thymus and bone marrow (where cells develop)
Secondary Lymphoid organs
Lymph nodes
Spleen
Mucosal associated lymphoid tissues MALT
Function of Lymph Nodes
Filters tissues borne antigens in regions rich with naive B and T cells —> allowing them to interact (which happens in the Cortex, paracortex and medulla of the lymph node)
Spleen Function
Filters blood born antigens
Has white pulp for immune response and red pulp for filtration
M-CSF
Stimulates the production and differentiation of monocytes and macrophages from hematopoietic stem cells
GM-CSF
Stimulates growth and maturation of WBC
G-CSF
Specifically stimulates the production and release of neutrophils from the bone marrow helping body fight infections
Thromboprotein
Regulates the production and maturation or platelets (thrombocytes)( from megakaryocytes in the bone marrow, marinating appropriate platelet levels in the blood
What does multipotent myeloid stem cell differentiate into
Myeloid progenitor and Lymphoid progenitor
What does myeloid progenitor differntiate into
Megakaryocyte —> Platelets
Erythroblast —> Reticulocytes —> RBC
Myeloblast —> Monocyte, Neutrophil, Basophil, Eosinophil
What does Lymphoid progenitor differntiate into
B-lymphocyte —> B plasma
T Lymphocyte
Natural Killer Cell
Function of RBCs
Nutrition (gas exchange)
Waste removal (pH and electrolytes; removal of carbon dioxide)
Thermoregulation (via vaso constriction and dilation)
Distribution (immune cells, cytokines, hormones and Immunoglobulins)