Haematology Flashcards
What is haemopoiesis?
-Physiological developmental process that gives rise to the cellular components of blood
Describe haemopoietic stem cells
- Differentiation potential for all lineages
- High proliferative potential
- Long term activity throughout the lifespan of the individual
- Self renewal
What is symmetrical self-renewal?
- One stem cell becomes 2 stem cells
- Inc stem cell pool
- No generation of differentiated progency
What is asymmetrical stem cells?
- One stem cell becomes a stem cell & a progenitor cell
- Maintains stem cell pool
- Generation of differentiated progency
What are the types of stem cells proliferation?
- Symmetric
- Asymmetric
- Lack of self-renewal
What happens in lack of self- renewal?
-One stem cell becomes 2 progenitor cells
-Deplete stem cell pool
-Generation of only differentiated progency
Or
-No stem cell division so maintains stem cell pool
What are the haemopoietic lineages?
- Myeloid= Granulocytes, platelets, erythrocytes
- Lymphoid= B/T lymphocytes
What are the origins of haematopoiesis
1) Ovum becomes trophoblast
2) 9days first signs of haemopoiesis
3) day 27 cells in aorta gonad mesonephros region expand rapidly
4) Disappears at day 40
5) Migration of heamatopoietic stem cells to the foetal liver
6) Becomes subsequent site of haematopoiesis
What is the function of blood cells?
- O2 transport
- Coagulation
- Immune response to infection
- Immune response to abnormal cells (malignancy)
What do granulocytes contain?
-Cytoplasmic granules: Neutrophils, basophils, eosinophils
Describe clinical changes in eosinophil count
basophil count
monocyte count
neutrophil count
- eosinophilia- parasitic infection, allergies
- basophilia- chronic myeloid leukaemia
- monocytosis- TB
- Most common. Inc no= neutrophilia- bacterial infection, inflammation, neutropenia
What are Natural killer cells?
- Innate immune system
- Large granular lymphocytes
- Recognise ‘non-self’ cells, viruses
What are B-lymphocytes?
- Adaptive immune system
- Rearrange immunoglobulin genes to enable antigen specific antibody production
- Humoral immunity
What are T-lymphocytes?
- Adaptive immune system
- Rearrange T cell antigen receptors
- Cell-mediated immunity
- Target specific cytotoxicity
- Regulate immune responses
- Interact with B cell macrophages
What is lymphocytosis & lymphopaenia?
- Cytosis= Inc lymphocytes: glandular fever, chronic lymphocytic leukaemia
- Penia= dec no. Post bone marrow transplant