What are the main stages of haemopoiesis?
Where are blood cells derived from?
Stem cells divide to form two new cells, one replaces the stem cell and the other goes on to differentiate
What are the two main cell lines that blood cells differentiate into?
Myeloid blasts - precursors of erythrocytes, granulocytes, platelets and monocytes
Lymphoblasts - precursors for lymphocytes
What regulates the rate of division and differentiation of blood cells?
Cytokines Eg erythropoietin
What is the function of red blood cells?
- Transport oxygen around body
- Carry haemoglobin
- Maintain haemoglobin in reduced state (ferrous)
- Maintain osmotic equilibrium
- Generate ATP
Describe how the size and shape of RBCs relates to their function
Biconcave flexible discs 8 um in diameter enabling them to travel through microvasculature with a minimum diameter of 3.5 um
Outline the process of the haemoglobin catabolism
- Haem - bilirubin in liver
- Stercobilin and urobilinogen in small intestine
Stercobilin excreted in faeces, urobilinogen excreted in urine via kidneys
What are reticulocytes?
List the three types of lymphocyte
T cell, B cell, Natural killer cells
Where do T cells differentiate?
What are the different forms of T cell and their function
CD4 T Helper cells - Activate B cells
CD8 T Killer cells - cytotoxic and stimulates apoptosis
What are the different forms of B cell and their function?
Plasma cell - produce antigen specific antibodies
Memory cell - retain antibodies for faster response to antigen or second exposure
What are monocytes?
Circulating cells that migrate to infected cells to become macrophages which are capable of phagocytosis and interaction of T cells
What are the functions of neutrophils?
What hormone stimulates neutrophil production and activity?
G-CSF (granulocyte colony stimulating hormone)
How long are neutrophils in circulation for?
What are eosinophils?
Cells that are capable of phagocytosis, allergic reactions and release of cytotoxic enzymes to destroy large particles
What are basophils?
Mediate acute inflammatory responses, contain histamines and heparin
What colours do eosinophils and basophils stain?
Basophils- dark purple
Where are platelets produced?
Megakarocytes in bone marrow
How are platelets involved in blood clotting?
- Capable of adhesion to damaged cell wall and aggregation with other platelets through glycoproteins on phospholipid membrane which also enables binding of clotting factors
- Alpha granules can release calcium ions