4 Flashcards
List 5 signs of anaemia
Signs: pallor, tachycardia, glossitis, koilonychia, dark urine
List 4 symptoms of anaemia
Symptoms: weakness, SoB, palpitations, fatigue
What is glossitis?
Swollen, red, painful tongue (vitamin B12 deficiency)
Koilonychia
Spoon nails (caused by iron deficiency)
Tinnitus
A sensation of noise (such as a ringing or roaring) that is typically caused by a bodily condition.
Role of vitamins B6 (folate) and B12 (cobalamin) in RBC production?
Deficiency of B6 or vitamin B12 inhibits purine and thymidylate syntheses, impairs DNA synthesis, and causes erythroblast apoptosis, resulting in anemia from ineffective erythropoiesis
What are erythropoiesis?
Production of red blood cells
Erythropoietin (EPO) regulates erythropoiesis
In what kind of anaemia is dark urine common?
Haemolytic anaemia
Define haematopoiesis.
Formation of the cells of immune system + blood cells.
What are haematopoietic stem cells (HSCs) + where do they reside?
Cells which can give rise to all the different blood cells.
In adults, under steady-state conditions, the majority of HSCs reside in bone marrow.
However, cytokine mobilization can result in the release of large numbers of HSCs into the blood.
As a clinical source of HSCs, mobilized peripheral blood (MPB) is now replacing bone marrow, as harvesting peripheral blood is easier for the donors than harvesting bone marrow.
Why are HSCs known as being self-renewing?
They reside in the bone marrow + when they proliferate, at least some of their daughter cells remain as HSCs so stem cell pool is not depleted (asymmetric division).
What is asymmetric division? Give an example.
Asymmetric cell division produces two daughter cells with different cellular fates. E.g. HSC proliferation.
What are the daughter cells of HSCs? Can they renew themselves?
HSCs – can renew themselves
Myeloid progenitor cells – cannot renew themselves
Lymphoid progenitor cells – cannot renew themselves
All blood cells are divided into which 2 lineages?
Lymphoid progenitor cells and Myeloid progenitor cells
What do myeloid progenitor cells divide into?
Erythrocyte
Megakaryocyte (> Thrombocyte)
Mast cell
Myeloblast:
- Granulocytes: Neutrophil, Eosinophil, Basophil
- Monocyte (> Macrophage)
What do lymphoid progenitor cells divide into?
Small lymphocytes:
- T cells
- B cells (> Plasma cells)
Large granular lymphocyte:
- Natural killer cells
What is a proerythroblast?
A precursor cells that will eventually become a RBC
Which vitamin are essential for DNA synthesis?
Vitamin B12
Vitamin B9 (folate)
Vitamin B6
What 2 things cause anaemia?
Reduced production of functional erythrocytes or production of defective haemoglobin.
Increased destruction of erythrocytes.
List 3 essential micronutrients that are critical in the production of erythrocytes and haem synthesis.
Vitamin B12 + B9 (folate)
Iron
What do the abbreviations in a full blood count mean: MCV, HCT, MCH, MCHC, RDW?
MCV – mean corpuscular volume (RBC size)
HCT – haematocrit (PCV – proportion of RBCs in blood)
MCH – mean corpuscular haemoglobin (average amount of haemoglobin in RBCs)
MCHC – MCH concentration (average % of haemoglobin in the RBCs)
RDW – red blood cell distribution width
List complications of SCA?
Vaso-occlusive crises
Visceral sequestration crisis
Haemolytic crises
Stroke
Hyposplenism
Ulcers
Which receptors do IgE antibodies bind to on mast cells?
FcεRI on mast cell where the Fc region of IgE binds to
What is sideroblastic anaemia?
Form of anaemia in which the bone marrow produces ringed sideroblasts rather than healthy erythrocytes.
What is pancytopenia?
Conditions affecting production of other cell types in addition to RBCs.
What is PRCA pure red cell aplasia?
Conditions affecting specifically erythropoiesis in the bone marrow.
What leads to pancytopenia?
Failure of HSCs to self-renew eventually leads to HSC exhaustion and pancytopenia.
What is haemolytic anaemia?
Premature destruction of functional erythrocytes by intrinsic or extrinsic mechanisms.
What are the 2 reasons why erythrocyte destruction usually occurs (extrinsic and; intrinsic)?
- Nothing wrong w/ the erythrocyte but they are destroyed by external pathological processes such as drugs, toxins, auto-antibodies or infection.
- Something intrinsically wrong w/ the erythrocyte so it’s destroyed. E.g. abnormal Hb, lacks certain enzymes
What is SCA caused by?
Mutation in the beta-globin gene
What does a RBC get broken down into (in the spleen/liver/red bone marrow)?
Globin - aa - reused for protein synthesis
Heme - liver (bilirubin and ferritin) - excretion
What are haemoglobinopathies?
Give an example.
Hemoglobinopathies are inherited single-gene disorders; in most cases, they are inherited as autosomal co-dominant traits
E.g. SCA
What does SCA affect?
Due to abnormally shaped SC erythrocytes issues w/ passage through circulatory system and ability to carry O2
What is a splenic sequestration crisis?
Intrasplenic sickling prevents blood from leaving the spleen and acute splenic engorgement ensues
What is a haemolytic crisis?
The rapid destruction of large numbers of red blood cells (haemolysis)
The destruction occurs much faster than the body can produce new red blood cells.
What is a vaso-occlusive crisis and its causes?
Sickle-shaped RBCs block blood vessels. Blood and oxygen cannot get to tissues, causing pain.
What characterises hypochromic and microcytic RBCs?
Hypochromic – pale RBCs
Microcytic – small RBCs
What is sideroblastic anemia caused by and characterised by?
Characterised by failure to incorporate iron into haem in erythrocyte precursor cells.
Caused by mutations/deletions of genes regulating expression of key enzymes in haem synthesis.
Describe what happens to broken down heme components.
Heme –>
Biliverdin and Fe3+ –>
Bilirubin and Fe3+ (goes to liver) –>
Bilirubin secreted in bile into the SI where it become urobilinogen –>
Urobilin (urine) / stercobilin (faeces)
What is the role of transferrin in the breakdown of haemoglobin?
Carries Fe3+ in the blood from macrophage to liver and liver to red bone marrow.
What does bilirubin get broken down into in the kidney and large intestines?
Kidney – urobilin
LI – stercobilin
What 2 components is heme broken down into?
Biliverdin and Fe3+
What happens to the globin broken down from RBCs?
Breaks down into amino acids and are reused for protein synthesis
Put these in order in starting from RBC being phagocytosed in liver, spleen, or red marrow: bilirubin, urobilinogen, biliverdin, urobilin.
Biliverdin, bilirubin, urobilinogen, urobilin
List the components of blood cells.
Erythrocytes, thrombocytes, leukocytes
List the components of blood plasma.
Water, proteins, inorganic ions, organic substances
What are the blood cells of the innate immune system?
Neutrophils, monocytes, basophils, eosinophils, mast cells, natural killer cells.
Type 1 hypersensitivity reactions are mediated by which type of antibody in humans?
IgE
In hypersplenism is MCV high, low or normal?
Normal
In liver disease is MCV high, low or normal?
High
In thalassemia is MCV high, low or normal?
Low
In iron-deficiency anaemia is MCV high, low or normal?
Low