L02: Haematopoiesis Flashcards
What are the broad groups of blood cells
Red cells/erythrocytes
Platelets
White cells/leukocytes
What is the main role of red cells
Oxygen transport
What is the main role of platelets
Clotting
What is the main role of white cells
Immunity
What are the subgroups of white cells
Lymphoid cells
Myeloid cells
What are lymphoid cells
T cells
B cells
NK cells
What are the myeloid cells
Mono yes
Granulocytes
What are the cell features of granulocytes
Contain granules
What are the specific granulocytes cells
Eosinophils
Basophils
Neutrophil
What type of immune system is involved in monocytes
Innate immunity
What happens to monocytes in the blood
Migrate into tissue and become macrophages
What is the role of macrophages
Engulf pathogens
Produces IL-12 and IFN gamma (cytokines)
Why are cytokines i.e IL-12 and IFN gamma important
Immunity against pathogens that get into cells
What type of immunity is involved with granulocytes
Innate immunity
What is the role of neutrophils
Engulf pathogens
Kill pathogens to kill
What do granules of the granulocytes contain
Lysosome and myeloperoxidase
What is the role of eosinophil and basophil
Kill pathogens via granules
Which role does eosinophils and basophils not do
Phagocytosis (engulf pathogens)
What immune system is involved in lymphocytes
Adaptive immunity
What is adaptive immunity
Learnt immune system
What is the origin of T cells
Thymus
What is the origin of B cell
Bone marrow
What is the origin of NK cell
Bone marrow
What is the role of platelets
Clotting
What are the cell features of platelets
No nucleus
Have granules
What is the role of granules in platelets
Secrete substances that control clotting and breakdown of blood clot
How are platelets removed
By macrophages in the spleen and liver
What does low levels of platelets lead to
Brushing and haemorrhage
Which cells are produced by haematopoiesis but are not measured in a full blood count (FBC)
Dendritic cells
Mast cells
What are dendritic cells
Antigen presenting cells found in tissues
What are mast cells
Produced in bone marrow but mature in tissues and are very similar to basophils
Acute inflammation in allergic reactions
List the blood cells from most to least in order
Red cells Platelets Neutrophils Eosinophils Basophils Lymphocytes
What is haematopoiesis
The process of blood cell production
What is haematopoiesis regulated by
Growth factors and cytokines
What is the site of haematopoiesis in infants
Bone marrow
What is the site of haematopoiesis in adults
Bone marrow
How does a haematopoietic stem cell become a terminally differentiated cell
Stem cells multipotent therefore they can become different differentiated cells
What is erythropoiesis
Development of red blood cells from a stem cell
What happens to the nucleus as a red blood cell forms
Nucleus becomes extruded
What are reticulocytes
The cell before it differentiates into a red cell
What are the cell features of RNA
Has RNA
What happens when there is a bleed
Erythropoiesis is increased to produced red cells
Which other cells during erythropoiesis can become pumped into the blood especially during a bleed
Reticulocytes
Which growth hormone controls erythropoiesis
Erythropoietin
Which organ produces erythropoietin
Kidney
When is erythropoietin released
Low oxygen which is sensed by oxygen sensors on the kidney
Why are people with chronic renal failure anaemic
Due to lack of production of erythropoietin
If red cells are being destroyed in the periphery what might you see on a blood film
Erythropoiesis is going to become stimulated so you might see reticulocytes
Which hormone regulates platelet production
Thrombopoietin
Which organ produces thrombopoeitin
Liver
What do you get when there is a block in haematopoesis and the cell produces without control
Acute leukaemia
What happens when you do not get any negative feedback on haematopoiesis
Chronic leukaemia
Apart from hormones what other substance is haematopoiesis under the control of
Transcription factor
What are transciption factors
Proteins that control gene transcription
How do we increase cell counts in clinical practise
Erthrocyte transfusion
Platelet transfusion
Haematopoietic stem cells
Erythropoietin - mainly used in end stage renal disease or Jehovah’s Witness
G-CSF- for neutropenic patients
Thrombopoeietin receptor agonist- to treat low platelet disorders
What are the 2 reasons that a cell count might be low
1) not being produced by the bone marrow i.e aplastic anaemia
2) being destroyed quickly in the blood i.e immune thrombocytopenia
How do we differentiate between aplastic anaemia and immune thrombocytopenia
By taking a bone marrow biopsy
What are the 2 types of bone marrow biopsy test
Aspirate
Trephine
What is an aspirate test
Extracts the semi-liquid bone marrow which is examined under the microscope to look at which cells are present
What is a trephine biopsy
Obtaining a core of bone marrow to look at cellularity and marrow infiltration by histology and immunohistochemistry