Erythropoiesis Flashcards
What percentage of blood is made up of Erythrocytes
90%
What other cells are present in blood
Leucocytes
Thrombocytes (platelets)
Why do erythrocytes have a biconcave disc shape
Increases surface area by around 20-30% increasing carrying capacity
What will failure of Na+ movement across the erythrocytes cell membrane
Leads to swelling and loss of the normal biconcave disc morphology
Describe dog erythrocytes
uniform in size, with a concave shape
Describe cat erythrocytes
smaller
anisocytosis (variation in size)
less concave
Describe the appearance of horse erythrocytes
Have a rouleaux formation (clustering of RBCs in standing blood)
Describe the apperance of ruminant erythrocytes
crenation (spiky)
variation in size
Describe the apperance of camelid erythrocytes
elipsoid in shape
What are some defining features of avian and reptile erythrocytes
- Nucleated
- Larger
immature erythrocytes may be rounded - cells can lose their nucleus and be termed erythroplastids
Why are erythrocytes so metabolically active
Energy is require to maintain the electrochemical gradient across the plasma membrane and of haemoglobin molecules
How do erythrocytes derive energy
By anaerobic metabolism of glucose (avoid consumption of O2 they are carrying)
What are the main roles of erythrocytes
- Transport of O2 from lungs to cells
- Transport of CO2 from cells to lungs
How is CO2 transported in the blood
Dissolved in plasma, bound to globin, or as bicarbonate ions in plasma
What percentage of erythrocyte protein is haemoglobin
95%
Describe haemoglobin
Made of 4 polypeptide subunits (2 infection all alpha ones and 2 identical beta ons), and is a water soluble globular protein.
A central haem group is found in the each of the polypeptide subunits, contains an iron atom to bind O2
What does haemoglobin do in areas of high oxygen concentration
Globin releases CO2 and iron binds to O2 (oxyhaemoglobin)
What does haemoglobin do in areas of low oxygen concentraion
O2 released and binds to CO2 (carbaminohaemoglobin)
What is released in hypoxic tissues to facilitate release of O2 from erythrocytes?
2,3-diphosphoglyceride (a carbohydrate)
What happens if haemoglobin binds nitric oxide
Causes dilation of the blood vessels
What compound has a greater affinity for haem than oxygen and can be fatal?
Carbon monoxide
What is haematopoiesis?
formation of blood cells
What is erythropoiesis?
production of red blood cells
Where does haematopoiesis occur?
red bone marrow and spleen
