Haemopoiesis Flashcards
What is Haemopoiesis?
Formation of blood cells
What do neutrophils do?
Phagocytosis
Acute inflam
What do eosinophils do?
Destroy parasites
Modulate hypersensitivity reactions
What do basophils do?
Modulate hypersensitivity reactions
What do macrophages do?
Modulate immune reactions
Phagocytic clearance
Regulate functions
What do lymphocytes do?
B cells - humoral immunity (antibodies)
T cells - Cell-mediated immunity - regulatory functions
NK cells - anti viral/tumour
What do erythrocytes do?
O2/CO2 transport
What do platelets do?
Primary haemostasis
What is proliferation?
Increase in numbers
What is differentiation?
Descendants commit to one or more lineages
What is maturation?
Descendants acquire functional properties and may stop proliferating
What is apoptosis?
Descendants undergo cell death
Where are stem cells derived from?
mesoderm
From when are circulating committed progenitors detectable?
Week 5
When does the yolk sac stop haemopoiesis?
Week 10
When does the liver begin haemopoiesis?
Week 6
When does the spleen begin haemopoiesis?
Week 12
When does the bone marrow begin haemopoiesis?
Week 16
What does bone marrow contain?
haematopoietic and non haematopoietic cells surrounded by a shell of bone with a neurovascular supply
What is found throughout the metaphysis?
Projections of bone called trabeculae
What is the interface of bone and bone marrow known as?
Endosteum which is covered by bone-lining cells including bone-forming osteoblasts and bone-resorbing osteoclasts
What do arteries feed into?
Sinusoids
What are sinusoids?
Specialised venules that form a reticular network of fenestrated (with apertures) vessels
How do red cells enter circulation?
They pass through fenestrations in endothelial cells
What migrates towards the sinusoid?
Neutrophils
What process do megakaryocytes go through?
Proplatelets
What is release of red cells into circulation associated with?
Sinusoidal dilatation and increased blood flow
What is the range in Myeloid:Erythroid ratio?
1.5:1 - 3.3:1
What regulated neutrophil maturation?
G-CSF (Granulocyte-colony stimulating factor)
What regulates growth and development of megalokaryocytes from their precursors?
Thrombopoieten
Name 3 things that regulate haemopoiesis?
Activation of transcription factors
Increased expression of CSF receptors
Transcription factor and CSF-induced maturation
