2. Haemopoiesis Flashcards
(26 cards)
What are the growth factors needed to stimulate stem cell differentiation into blood cells?
- Erythropoietin (RBCs)
- Colony Stimulating Factors (WBCs)
- Interleukins (regulate cell growth)
- Thrombopoietin
What is extramedullary haematopoiesis?
When liver, thymus and spleen resume haematopoietic function
Neutrophils
Phagocytes
High number indicates bacterial infection
Can’t be dyed
Polymorphonuclear
Eosinophils
Stain brick red with eosin
Granules contain histamine, RNase and DNase
Combat viral and parasitic infection
Basophils
Large cytoplasmic granules
Make and store histamine and heparin
Stages in erythropoiesis
- Proerythroblast
- Basophilic erythroblast
- Polychromatic erythroblast
- Orthochromatic erythroblast
- Reticulocyte
- Mature RBC
How are RBCs recycled?
Globin amino acids and iron reutilised
Haem excreted in bile
What is needed for erythropoiesis?
Amino acids
B12 and folate
Iron
Signs of anaemia
Fatigue and weakness Pallor Koilonychia Angular stomatitis Glossitis
Types of anaemia
Hypochromic-microcytic
Normochromic macrocytic
Polychromatophilic macrocytic
Hypochromic-microcytic
Most common
Due to blood loss, inflammatory diseases, cytotoxic treatments or chronic kidney disease or heart failure
Megaloblastic anaemia
Macrocytic: RBCs are big, odd shape
Vit b12 deficiency
Lack gastric intrinsic factor, so more b12 is destroyed in stomach
Haemolytic anaemia
Decreased life span of RBCs
Sickle cell anaemia or ABO/ Rhesus incompatibility
Polycythaemia
Too many RBCs
Primary: mutation, increased viscosity
Secondary: Rate of prod adapts in response to low oxygen
Relative: Loss of fluid but not RBCs, dehydration
What percentage of blood is plasma?
55%
What is it called when the liver, thymus and spleen take over haemopoiesis?
Extramedullary haematopoiesis
Describe the organelles within platelets
No nuclei
Have organelles and cytosolic enzymes for generating energy and synthesising secretory products
How long do platelets remain functional for?
10 days
What are platelets removed from circulation by?
Tissue macrophages
How are platelets released from the spleen?
Sympathetically induced splenic contraction
What are the benefits of the RBC’s biconcave shape?
Increases surface area
Thinness enables oxygen to diffuse rapidly
What does FBC stand for?
Full Blood Count
Why might you check the percentage of reticulocytes in the blood?
Useful index of erythropoietic activity in the bone marrow
Why is a vitamin B12 deficiency slow to manifest?
Body stores 3 years supply of B12
