Haematopoesis Flashcards
What is haemopoesis?
Production of blood cells
Where does haemopoesis occur?
Bone marrow
What hormone controls the production of erythrocytes?
Erythropoietin
What hormone controls the production of granulocytes?
G-CSF
What hormone controls the production of lymphocytes?
Interleukins
TNFs
What hormone controls the production of megarkaryocytes/platelets?
TPO
What is the reticuloendothelial system?
Network of blood and tissues which is part of the immune system containing phagocytic cells
What are the main organs of the RES?
Spleen
Liver
What happens to RBCs as they pass through the spleen?
Damaged or old cells are destroyed
What is the structure of the spleen?
Red pulp
- sinuses line by endothelial macrophages
- RBCs pass through
White pulp
- similar structure to lymphoid follicles
- WBCs pass through
What are the functions of the spleen?
Sequestration + phagocytosis of RBCs
Blood pooling
Extramedullary haemopoesis
Immunological function
What can cause splenomegaly?
Back pressure - portal hypertension
Overworking red/white pulp
Extramedullary haemopoesis
Infiltration
What is hyposplenism?
Lack of functioning splenic tissue
What causes hyposplenism?
Splenectomy
Sick cell disease
Coeliac disease
What can be seen on a blood film in hyposplenism?
Howell Jolly bodies - DNA remnants
What are the functions of RBCs?
Deliver oxygen to tissues
Carry haemoglobin
Maintain haemoglobin in reduced state
Maintain osmotic equilibrium
How is erythropoiesis controlled?
Reduced pO2 detected by peritubular cells in kidney
Increased production of erythropoietin by kidney
Erythropoietin stimulates maturation and release of RBCs from marrow
RBCs increase = fall in erythropoietin production
What is cytopenia?
Reduction in blood cells
What is anaemia?
Low red cell count
What is leucopenia?
Low white cell count
What is neutropenia?
Low neutrophil count
What is thrombocytopenia?
Low platelet count
What is pancytopenia?
Low RBCs, WBCs and platelets
What is eryhrocytosis?
High red cell count
What is leucocytosis?
High white cell count
What is neutrophilia?
High neutrophil count
What is lymphocytosis?
High lymphocyte count
What is thrombocytosis?
High platelet count
What is the appearance of neutrophils?
Lobed nucleus
What can cause neutrophilia?
Acute inflammation Tissue damage Cancer Acute haemorrhage Infection
What can cause neutropenia?
Immune destruction
Sepsis
B12/folate deficiency
Aplastic anaemia
What are consequences of neutropenia?
Severe life threatening bacterial infection
Severe life threatening fungal infection
Mucosal ulceration
What are the roles of monocytes?
Respond to inflammation and antigenic stimuli
Phagocytosis
Pinocytosis
What can cause monocytosis?
Chronic inflammatory conditions
Chronic infection
Carcinoma
Myeloproliferative disorders
What are the roles of eosinophils?
Deal with some parasites
Mediator of allergic response
Mediate hypersensitivity reactions
What are in eosinophil granules?
Arginine
Phospholipid
Enzyme
What can cause eosinophilia?
Allergic diseases
Parasitic infection
Lymphoma
Leukaemia
What are the roles of basophils?
Active in allergic reactions and inflammatory conditions
What are in basophil granules?
Histamine
Heparin
Hyaluronic acid
Serotonin
What can cause basophilia?
Hypersensitivity reactions
UC
RA
Myeloproliferative diseases
What cells come from lymphocytes?
B cells
T cells
Natural killer cells
What can cause lymphocytosis?
Viral infections
Bacterial infections
Lymphoproliferative disorders
