Physiology of blood cells and haematological terminology Flashcards
What are the 2 main types of stem cell in the bone marrow?
- Pluripotent haemopoietic
2. Pluripotent lymphoid-myeloid
Recall the pathway of blood cell production from pluripotent haemotopoeitic stem cells
PHSC –> multipotent myeloid stem cell (MYELOBLAST) –> erythrocyte/ megakaryocyte/ granulocytes/ monocytes
Recall the pathway of blood cell production from pluripotent lymphoid-myeloid stem cell
PLMSC –> lymphoid stem cell (LYMPHOBLAST) –> T/B/ NK cell
What are the 2 pathways of stem cells following division?
- Self-renew
2. Produce mature progeny
Recall the location of erythropoietin production and the relative amounts produced in each location
90% - juxtatubular interstitial cells in kidney
10% - hepatocytes and liver interstitial cells
How is erythropoietin destroyed?
Phagocytic spleen cells
What 2 conditions can increase erythropoietin production?
Anaemia
Hypoxia
What is the intravascular life span of neutrophils?
7-10 hours
How are neutrophils attracted to sites of inflammation?
Chemotaxis (cytokines)
What is the main role of eosinophils?
Protection against parasitic infection
What is the main role of basophils?
Allergy
What is the origin of monocytes?
Myeloblasts
Recall the 2 functions of monocytes
- Scavenger/ phagocytic function
2. Storage and release of iron
What sort of cells do monocytes give rise to in the liver?
Kuppfer cells
How long do platelets last in the circulation?
10 days
What are the 3 main roles of platelets in primary haemostatis?
- Contribution of phospholipid
- Maintain integrity of endothelium
- Plug formation
Recall the life span of lymphocytes
Highly variable
What is the immediate precursor of platelets?
megakaryocytes
Define “anisocytosis”
Red cells showing more variation in SIZE than is normal
Define “poiklocytosis”
Red cells showing more variation in SHAPE than is normal
What is a “target cell”?
Red cell with an accumulation of Hb in the centre of the pale area
Recall 4 causes of target cells in blood
- Obstructive jaundice
- Liver disease
- Haemaglobinopathy
- Hyposplenism
What is a Howell-Jolly body and in what sort of cells do they appear?
Remnants of nucleus - target cell erythrocytes
Give 2 causes of elliptocytic red cells
- Hereditary elliptocytosis
2. Iron deficiency
What proportion of the red cell surface is “central pallor” in normal cells, and what terms are used to describe red cells that have a too high/ too low proportion of central pallor?
1/3
Hypochromia (too large an area) and hyperchromia (lack central pallor)
What does hypochromia usually go together with?
Microcytosis
What are the 2 main causes of hyperchromia?
- Spherocytes
2. irregularly contracted cells
What causes spherocyte formation?
Loss of membrane without equivalent loss of cytoplasm
What is the usual cause of irregularly contracted cells?
Oxidant damage to the cell membrane and Hb
What is “polychromasia” and when is it seen?
Increased blue tinge to red cell cytoplasm
Indicates red cell is young
What stain can be used to detect young cells?
Methylene blue
What terminology is given to there being too much/ too many types of a type of blood cell?
Cytosis or philia
What are the 2 methods of counting young cells?
- Count polychromatic cells
2. Methylene blue
What is the cause of sickle cells?
Polymerisation of HbS when it’s in a high concentration
What is a fragment of a red cell referred to as?
Schistocyte
What is rouleaux?
Stacks of red cells
What is rouleux the result of?
Alteration in plasma proteins that makes erythrocytes adherent (eg in multiple myeloma)
How do agglutinates differ from rouleaux?
Irregular clumping
What causes agglutinates to form?
IgM on surface
Why are Howel-Jolly bodies linked to hyposlenism?
In a normally functionning spleen they are also produced but are removed by the spleen
What are the terms used to refer to too many/ too few white cells?
Leucosytosis
Leucopenia
What are the terms used to refer to too many/ too few neutrophils?
Neutropenia
Neutrophilia
What are the terms used to refer to too many/ too few thrombocytes?
Thrombocytopenia
Thrombocytosis
What is infectious mononucleosis?
Glandular fever
What is left shift?
There are things in the blood from further back than there ought to be, more immature cells + band forms
What might cause left shift?
Infection
What pathology is toxic granulation a sign of, and when is it normal?
Infection
Pregnancy
In someone with a B12/ folic acid deficiency, how might neutrophils appear?
Hypersegmented nuclei
