Flashcards in BLOOD Deck (51)
what is haematocrit?
the ratio of volume of RBC to total volume
what is haematopoiesis?
the formation of new blood cells and platelets
what is anaemia?
reduced haemoglobin or numbers of RBCs
often due to iron deficiency
male < 130 g/L
female < 110 g/L
what is haemostasis?
the arrest of bleeding
this involves the physiological processes of coagulation and contraction of damaged blood vessels
what is haemophilia?
the inability to make new blood clots due to factor VIII deficiency (haemophilia A) or factor IX (haemophilia B)
what are the components of blood?
fluid = 55%
cellular = 45%
where are precursor cells found in adults?
in axial bone marrow
where are precursor cells found in children?
in bone marrow of all bones
where are precursor cells found in embryos?
what are stem cells?
they are pluripotent and can differentiate into any blood cell (RBC, WBC or platelets)
what is the process of red blood cell production?
what is the hormonal stimulating factor for erythrocyte production? Where is it made?
made in kidneys
what is the process of white blood cells production?
what is the hormonal stimulating factor for white blood cell production? what does it stimulate?
granulocyte-macrophage colony stimulating factor (GMCSF)
stimulates production of myeloblastic WBCs and not lymphoid cells
what is the process of platelet production?
what is the hormonal factor for platelet production? What is it's effect?
leads to increased megakaryocytes which platelets bud off from
what is the lifespan of erythrocytes?
what is the structure of erythrocytes?
- no nucleus and no mitochondria
- contain haemoglobin
how are red blood cells removed?
by spleen, liver and bone marrow and through blood loss
what is the role of haemoglobin?
carries O2 from lungs to tissues
what is the structure of haemoglobin?
tetrametric protein with 4 globin chains
each has a haem group - capable of oxygen binding
what is the difference between adult and foetal haemoglobin?
adult = 2 x alpha and 2 x beta haemoglobin chains
foetal = 2 x alpha and 2 x gamma haemoglobin chains
what is thalassaemia?
mutations / absence of alpha or beta chains in adult haemoglobin
what are the symptoms of anaemia?
hyperventilation on exertion
what are the causes of anaemia?
- acute blood loss
- production mismatches
- increased removal of RBCs
- deficiencies of iron, folate or vitamin B12
what is hypoplastic anaemia?
doesn't produce enough blood cells
what is dyshaemotpoeitic anaemia?
ineffective production of blood cells
what is haemolytic anaemia?
increased removal of RBC
what is macrocytic anaemia?
deficiency in folate