Theme 7: Haematology Flashcards
Which physiological developmental process gives rise to the cellular components of blood?
Haemopoiesis
Which type of cell replication increases the stem cell pool, generating no differentiated progeny?
Symmetrical self-renewal
Stem cell divides forming 2 daughter stem cells
With reference to haemopoietic stem cells, what is asymmetric self-renewal?
Division maintains the stem cell pool (no increase, no decrease). This is achieved by forming one stem cell and one differentiated cell.
With reference to haemopoietic stem cells, what is lack of self-renewal?
Can mean 2 things:
- maintain the stem cell pool, no division takes place
- deplete the stem cell pool, each division generates 2 differentiated daughter cells
Which haemopoietic stem cell lineage produces erythrocytes?
Myeloid
Which haemopoietic stem cell lineage produces platelets?
Myeloid
Which haemopoietic stem cell lineage produces B-lymphocytes?
Lymphoid
Which haemopoietic stem cell lineage produces basophils?
Myeloid
Which haemopoietic stem cell lineage produces T-lymphocytes?
Lymphoid
Haemopoiesis starts at day 27 in the __1__ region, expands rapidly at day 35 and disappears at day __2__.
1) aorta gonad mesonephros (AGM)
2) 40
The disappearance of the aorta gonad mesonephros region at day 40 coincides with what event?
Migration of the haemopoietic stem cells into the foetal liver, which becomes the new site of haemopoiesis
Reduced erythrocyte count is called what?
Anaemia
What term describes a state of raised RBC count?
Polycythaemia
What term describes a state where the % of RBC in the blood is raised because the volume of plasma is reduced?
Relative polycythaemia
The RBC count isn’t raised, but as the plasma volume has dropped it appears to be high in comparison with the plasma
What is the most common white cell in adults?
Neutrophils
Which of the following facts about neutrophils is incorrect?
a) They are phagocytic
b) They live for only a few hours in the blood
c) Malignant conditions (such as myelodysplasia) can increase the number of lobes on the nucleus
d) Numbers are usually raised in response to a bacterial infection
c) Malignant conditions (such as myelodysplasia) can increase the number of lobes on the nucleus
Neutrophil have multi-lobed nuclei. The number of lobes can be:
- reduced in malignant conditions (e.g. myelodysplasia); or,
- increased (hypersegmented neutrophils) in anaemia, B12 deficiency, folate deficiency.
What term means:
Raised number of neutrophils
Neutrophilia
Causes include bacterial infection and inflammation
What term means:
Decreased number of neutrophils
Neutropenia
Causes include drug side effects
Which WBCs are granulocytes?
Neutrophils, eosinophils, basophils
Which granulocyte has a bi-lobed nucleus?
Eosinophil
What effect might a parasitic infection have on numbers of eosinophils?
Cause eosinophilia (increased number)
Which granulocyte has a dark cytoplasm with lots of granules?
Basophils
What effect can chronic myeloid leukaemia have on numbers of basophils?
CML can cause basophilia: increased numbers
Raised basophil count is diagnostic of CML. This is because it is the only condition that causes basophilia. It also increases the numbers of the other myeloid lineage, but other things can also cause that.
What is the difference between a monocyte and a macrophage?
They are the same cells, but monocytes are in circulation and become known as macrophages or histiocytes when they enter the tissues.
What are Kupffer cells?
Macrophages in the liver
What are Langerhans cells?
Macrophages in the skin
What effect might TB have on numbers of monocytes?
Monocytosis: increased numbers of monocytes
Which WBCs are phagocytic & antigen-presenting cells?
Monocytes
Which of the following is likely to lead to lymphopenia?
a) Glandular fever
b) Bone marrow transplant
c) Chronic lymphocytic leukaemia
d) Pertussis
b) Bone marrow transplant
It can take years for lymphocyte numbers to normalise following a bone marrow transplant as they generate quite slowly.
The other conditions would all lead to lymphocytosis.
Which type of lymphocyte(s) form part of the innate immune system?
Natural killers (NK)
These lymphocytes identify self and non-self; launching an attack on non-self.
Which lymphocytes include multiple subtypes, such as CD4 and CD8?
T-lymphocytes
Are T-lymphocytes part of the innate immune system or the adaptive immune system?
Adaptive
Are B-lymphocytes part of the innate immune system or the adaptive immune system?
Adaptive
Platelets are derived from __?__ in the bone marrow
Megakaryocytes
Fragments of these large cells break off and enter circulation as platelets.
What results are included with a FBC?
- Haemoglobin concentration
- Red cell parameters: mean cell volume (MCV) and mean cell Hb (MCH)
- WCC
- Platelet count
What three things are assayed as part of the coagulation screen?
Prothrombin time
Thrombin time
Activated partial thromboplastin time
Which test involves hollow-needle biopsy from the posterior iliac crest of the pelvis under local anaesthetic?
Bone marrow aspirate and trephine
Liquid marrow is aspirated and then a core is removed using a trephine (a cylindrical hole saw used in surgery to remove a circle of tissue or bone)
What term is used to describe the proportion of abnormal results correctly classified by a test?
Sensitivity
Sensitivity (also called the true positive [sick] rate) measures the proportion of actual positives that are correctly identified as such (e.g., the percentage of sick people who are correctly identified as having the condition)
What is meant by specificity of a test?
Specificity (also called the true negative rate) measures the proportion of actual negatives that are correctly identified as such (e.g., the percentage of healthy people who are correctly identified as not having the condition)