Case 14 Flashcards
What is haematopoesis?
Process of how body creates blood cells
What are erythrocytes?
Red blood cells
Structure of erythrocytes?
Small, flexible , bioconcave discs, no nucleus, high haemoglobin conc
What are leukocytes?
White blood cells
What are thrombocytes?
Platelets
Structure of thrombocytes?
(Platelets)Small disc shaped fragments without a nucleus
Function of thrombocytes?
(Platelets) Bloodclot formation, aid vasoconstriction, aid in wound healing, part of immune response, part of angiogenesis (formation and growth of new blood vessels)
What is the composition of blood?
55% Plasma, 1% Leukocytes (wbc) and Thrombocytes (platelets) , 45% Erythrocytes (rbc)
Lifespan of platelets?
9/10 days
Lifespan of erythrocytes?
(RBCs) 120 days
Lifespan of leukocytes?
(WBCs) a few days - a few years
What are the 3 layers of blood (when separated by centrifugation) and what are their percentages of the total?
Plasma 55%, Buffy coat <1% and Red blood cells 45%
What is contained in plasma?
Clotting factors
What is contained in buffy coat?
White blood cells (leukocytes) and platelets
Site of Haematopoesis in 0-2 month fetus?
Yolk sac
Site of Haematopoesis in 2-7 month fetus?
Liver, spleen
Site of Haematopoesis in 5-9 month fetus?
Bone marrow
Site of haematopoesis in infant?
Bone marrow of practically all bones
Site of haematopoesis in adult?
Bone marrow of: vertebrae, ribs, sternum, skull, sacrum and pelvis, proximal end of femur
Composition of bone marrow at birth?
100% Red
Composition of bone marrow of adults?
50% red 50% yellow
What is contained in yellow bone marrow?
Fat cells & stromal cells and stromal matrix
What are stromal cells?
Many different types of cell which support and regulate production of blood cells in bone marrow
What is stromal matrix?
A specialised extra cellular matrix in bone marrow containing proteins and other molecules to support Haematopoesis
What is erythropoesis?
Production of red blood cells
Describe process of erythropoesis?
1)Haematopoetic stem cells
2)become Erythroid progenitor cells
3)become Erythroblasts
4)Erythroblasts start producing haemoglobin and start maturing
5)become normoblasts
6)Late normoblasts have nucleus exrtuded
7)become reticulocytes (immature RBCs)
6)become erythrocytes (mature RBCs)
What is thrombopoesis?
Production of platelets
Process of thrombopoesis?
1)Haematopoetic stem cells
2)Become megakaryocytes
3)Undergo endomitosis - chromosomes replicate but nucleus doesn’t so cell gets very big
4)Proplatelets (which are small protrusions) form in cytoplasm of megakaryocytes
5)Proplatelets extend out into blood vessels in bone marrow
6)Proplatelets fragment into platelets
What are leukocytes?
White blood cells
What are the 2 main groups of leukocyte?
Granulocytes and Agranulocytes
3 examples of types of granulocytes?
Neutrophils, Eosinophils, Basophils (types of white blood cells)
What are the 2 types of agranulocytes?
Lymphocytes and Monocytes
What is granulopoesis?
Production of granulocytes (type of white blood cell)
Process of granulopoesis?
1)Haematopoetic stem cells
2)Become myeloid progenitor cells
3)become myeloblasts
4)become promyelocytes
5)become myelocytes
6)become band cells
7)mature band cells released into blood stream and migrate into different tissues
8)band cells differentiate into tissue-resident-granulocytes
(Either neutrophils/eosinophils/basophils)
What is lymphopoeisis?
Production of lymphocytes (types of white blood cell)
2 examples of lymphocytes?
T cells and B cells
Process of T cell lymphopoesis?
1)Haemopoetic stem cells
2)become lymphoid progenitor cells
3)LPCs move to thymus
4)become thymocytes
5)mature to become T cells
Process of B cell lymphopoesis?
1)Haemopoetic stem cells
2)become lymphoid progenitor cells
3)LPCs move to bone marrow
4)become Pre B cells
5)become B cells
What is monopoesis?
Production of monocytes (type of white blood cell)
Process of monopoesis?
1)Haematopoetic stem cells
2)become myeloid progenitor cells
3)become monoblasts
4)become promonocytes
5)become monocytes
What are transcription factors?
Proteins which regulate rate of transcription by binding to DNA sequences and activating and repressing gene expression
What are growth factors?
Regulate cell growth, proliferation, differentiation and survival by binding to specific receptor on surface of target cells
Which hormone regulates red blood cell production, and when is it produced and where?
Erythopoietin, produced by kidney in response to low oxygen levels
Antigens present on red blood cells of blood group A?
A
Antibodies present in plasma of blood group A?
Anti-B
Antigens present on red blood cells of blood group B?
B