Haematopoiesis Flashcards
Why can erythrocytes not repair themselves?
They don’t have DNA or RNA (no nucleus)
Where does the production of red blood cells happen?
In bone marrow
What is the average life span of erythrocytes?
90-140 days
What 4 main structures are predominantly for red blood cell production?
Ribs
Vertebrae
Sternum
Pelvic bone
What cells do erythrocytes derive from?
Stem cells
Name 4 nutritional diet factors important for erythrocyte production?
Any from: Iron protein copper vit B2 vit B6 vit B12 Folic acid - helps with iron
What are cytokines?
Tiny signalling proteins that are released by cells to regulate differentiation in stem cells (tell the bone marrow what cells are needed in the body)
What are the only 2 types of white blood cells formed in the bone marrow?
Granulocytes
Monocytes
What is a platelet also known as?
Thrombocytes
Why do platelets not undergo mitosis?
Have no nucleus
How big are thrombocytes?
about 1/10th of a erythrocyte
What happens to the stem cells as they differentiate into erythrocytes?
they fill with haemoglobin
Nucleus becomes smaller
What is a leukocyte
A white blood cell
What is a erythrocyte
A red blood cell
What is a lymphocyte?
A type of white blood cell involved in the immune system (two types = B cells and T cells)
Define Haematopoiesis
the formation of blood cellular components
When do lymphocytes leave the bone marrow in development?
at the end of fetal development
What are thrombocytes also known as?
Platelets
Why can platelets/ thrombocytes not undergo mitosis?
They do not have a nucleus
What are thrombocytes made from?
Megakaryocytes
How are thrombocytes made?
pieces of megakaryocytes in the bone marrow break off
What do thrombocytes do?
They form blood clots to slow or stop bleeding and help wounds heal
What are monocytes?
A type of white blood cell that can differentiate into macrophages and dendric cells
At what stage of erythropoiesis does ribosome synthesis happen?
At early erythroblast stage
At what stage of erythropoiesis does haemoglobin accumulate?
At late erythroblast stage
What are the 7 transformations of erythropoiesis?
Stem cell Proerythroblast Early erythroblast Late erythroblast Normoblast Reticulocyte
At what stage of erythropoiesis do cells lose the nucleus?
Reticulocyte stage
Where are macrophages found?
Spleen, liver, bone marrow
What do macrophages do?
Engulf old erythrocytes and break them down
What is haemoglobin broken down into?
Globin
Heme
What is heme further broken down into?
Bilirubin & Iron
What is globin further broken down into?
amino acids
Where does erythrocyte removal/ breakdown occur?
Spleen, liver, bone marrow
What are macrophages?
specialised cells involved in detection, phagocytosis and destruction of bacteria/ other harmful organisms
What is phagocytosis?
process by which certain living cells called phagocytes ingest or engulf other cells or particles
Which signalling protein regulates haematopoiesis?
Cytokines
What happens to the amino acids from globin after erythrocyte breakdown?
they re-enter circulation to be used in erythropoiesis again in bone marrow
which hormone is responsible for erythropoiesis?
erythropoietin (EPO)
Which mineral is essential for haemoglobin production?
Iron
What does a high level of transferrin indicate?
Low iron - iron deficiency anemia
Where does iron obtain a transporter from?
the liver
What transporter carries iron back to bone marrow after breakdown of erythrocytes?
transferrin
How does bilirubin travel to the liver for excretion?
via albumin (a transporter)
What does albumin do?
carries bilirubin to the liver
When would you find particularly high levels of erythropoietin?
during hypoxia
What would an increased number of reticulocytes indicate ?
blood loss or certain diseases where red blood cells are destroyed prematurely – i.e: haemolytic anemia
what is haemolytic anemia
A condition where red blood cells are destroyed faster than they can be mad
what may indicate haemolytic anemia
an increased number of reticulocytes
what reason may reticulocyte numbers increase that is not a condition?
being at high altitudes
which organ produces erythropoietin
kidneys
What is anaemia?
Reduction in red blood cells
what are 3 things that can cause anaemia?
Bleeding Bone marrow failure Erythropoietin deficiency Chronic kidney disease Cancer Medications
which type of leukocyte can differentiate into macrophages
Monocytes
which type of leukocyte has small granules containing protein
Granulocytes
