Haematology Physiology Flashcards
What are the broad steps of Haemotopoiesis?
Pluripotent Haematopoietic stem cells
1) –> Uncommitted Stem Cells –> Myeloid Cells
2) –> Lymphocyte Stem Cells –> Lymphocytes
What are the myeloid cells? [6]
- Erythrocytes
- Platelets
- Neutrophils
- Monocytes
- Basophils
- Eosinophils
What are the lymphoid cells? [5]
Lymphocytes Neutrophils Monocytes Basophils Eosinophils
What hormone drives RBC production?
RBC lifespan
Erythropoietin
120 days
What hormone drives platelet production and where’s it made?
Lifespan of a platelet?
Thrombopoietin made in the liver
7 days
What drives neutrophil production? [2]
Stimulated:
- Interleukins
- Colony Stimulating Factors (CSF)
Lifespan of a neutrophil?
1-2days
What can we use to improve neutrophil number? [2]
G-CSF in neutropenia
Function of the following myeloid cells:
Neutrophils [2]
Eosinophils [2]
Basophils [1]
Neutrophils - target bacteria and fungi
Eosinophils:
- Target parasites that are too big to be phagocytosed
- Modulate allergic inflammatory responses
Basophils: release histamine for inflammatory responses
How does the body identify different lymphocytes?
By surface antigen (aka CD markers)
What do the different lymphocytes do and where are they matured? [3]
B cells make antibodies. Mature in marrow
T cells split into helper, cytotoxic, regulatory
Mature in Thymus
NK cells: kill virus-infected and tumor cells
From what process in the development of T cells do lymphoma’s arise?
DNA recombination during production. This process ensures all lymphocytes are a little different
But it can go wrong leading to lymphoma
What is T cell +ve selection?
If gene rearrangement results in a functional receptor the cell is allowed to survive
What is T cell -ve selection?
Gene rearrangement leads to a self-recognising T cell which is then killed
How do our bodies identify self cells?
By HLA surface antigens
What are the types of HLA?
Class 1 - Displays own antigens on all nucleated cells
Class 2 - displays the antigens eaten by antigen-presenting cells
What’s the normal range for Haemoglobin, platelets & WBC?
WBC 4-10 x10^9/L
Platelets 150-400 x10^9/L
Haemoglobin 140-180 in men or 120-160g/L in women
What are the consequences of hypersplenism?
Pancytopenia
What are the consequences of hyposplenism?
Capsulated Bacteria Infection
Red Cell Changes
Describe the process of a red cell being created?
Haemotocytoblast (stem cell)
- Proerythroblast (committed cell)
- Erythroblast
- Normoblast
- Reticulocyte (released into blood)
- Erythrocyte
What components are required in RBC production [4]
Metals
Vitamins
Amino acids
Hormones
What metals are required for RBCs? [4]
What vitamins are required to make RBCs? [6]
What hormones are essential to RBC development? [4]
Metals - iron, copper, cobalt, manganese Vitamins - B12, folic acid, thiamine B1, B6, C, E Hormones - Erythropoietin - GM-CSF - Androgens, thyroxine - SCF
What cell breaks down RBCs? [2]
Macrophages in the reticuloendothelial system tissues i.e. spleen, liver, lymph nodes etc
What becomes of haemoglobin after a RBC is broken down? [3]
Globin –> Amino acids (recycled)
Haem –> Iron (recycled)
Heme –> Bilirubin (excreted) - conjugated in liver
How does iron enter from the gut? [2]
Bound to enterocytes and transported to the plasma by ferroportin protein
What happens to Fe once it enters circulation? [2]
Transported around by transferrin
Then it’s stored in tissues as ferritin
What does Hepcidin do? [2]
Blocks ferroportin causing decreased iron absorption
It’s produced by hepatocytes in response to inflammation and high iron levels
What factors can lower haemoglobin affinity for O2? [4]
Acidosis
Hyperythermia
Higher DPG
Hypercapnia
What makes up a normal adult haemoglobin (HbA)? [3]
1 Haem Molecule
2 Alpha globin chains
2 Beta globin chains
