Chapter 33 Flashcards
What are the functions of RBC?
As it contains haemoglobin, it acts as acid buffer and also transport of oxygen and carbon dioxide
It also contains carbonic anhydrase enzyme
What is the amount of RBC in men and women?
In men, it is 5.2 million
In women, it is 4.7 million
What is the average volume of RBC in the blood?
RBC covers 90 to 95 mm³ of blood
What is the shape and size of RBC?
RBC are biconcave cells with 1 µm thickness in the centre and 2.5 µm on the periphery with 7.8 µm diameter
What is the advantage of RBC of having extra cell membrane?
RBC have extra cell membrane, then the content in it, so that it can squeeze through the blood capillaries easily
In different phases of life, where are the RBC produced?
During fetal life, first in the York sac, then in the second trimester in the liver spleen and lymph nodes, and after birth, it is produced in the bone marrow
In an adult, where are the RBC produced?
Only in the membranous bones
All type of blood cells are formed from which cell ?
Pluripotential stem cells
What are committed stem cells?
Pluripotential stem cells that are committed to a single cell line
What is colony forming unit - erythrocytes?
They committed stem cells that are committed to form erythrocytes in the future
What are growth inducers?
The factors that induce growth and reproduction of the virtually all types of cells
For example IL-3
What are differentiation inducers?
The factors that induce the differentiation of a committed cell to one or more step towards the final adult cell
Which factors influence the production of growth and differentiation factors?
The factors outside the bone marrow affect its production
What are the stages of erythropoiesis?
Proerythroblast
Basophilic Erythro blast
Polychromatophilic Erythro blast
Orthochromatic erythroblast
Reticulocyte
Erythrocyte
What regulates the erythropoiesis?
The production of erythropoietin
In which cases the need for Erythropoietin production arises?
Anaemia, high altitude, diseases like cardiac failure and lung disease and in the destruction of bone marrow
What is erythropoietin?
It is a hormone and glycoprotein with a molecular weight of 34,000
Where is the erythropoietin formed?
90% of it is formed in the kidney by the fibroblast like interstitial cells of the tubules
10% is formed by the liver and other cells
What is the process of formation erythropoietin?
Renal hypoxia occurs, then hypoxia inducible factor-1 is stimulated which is a transcription factor that binds to hypoxia response element in the erythropoietin gene and causes the formation of mRNA
What are the factors required for the maturation of RBC?
Vitamin B12 and folic acid
What happens in the deficiency of vitamin B12 and folic acid?
As both of these are required for the maturation of nuclei by the formation of thymidine triphosphate
Deficiency result in the failure of nuclear maturation due to which the lifespan of RBC decreases, and they have flimsy membranes so form macrocytes
In which case, vitamin B12 absorption decreases?
In the case of atrophic gastric mucosa
As it results in the deficiency of intrinsic factor, which is responsible for the absorption of vitamin B12 in the intestine
It causes pernicious anaemia
In which case folic acid deficiency occurs?
In the small intestinal disease called sprue
There is deficiency of folic acid, as it doesn’t absorb properly in the intestine
