Rec blood cells etc chapter 33 Flashcards
Functions of rbc
its function is to transport hemoglobin. Which in turn trasports oxygen from lungs to the tissues of the body
It has carbonic anhydrase, at enzyme that catalyses the reversible reaction between co2 and water, allows co2 to be carried in rbc as bicarbonate ions and diffuse out of blood
It act as an acid base buffer
Shape and size of RBC
shape is biconcave
Diameter is 7.8 micrometer, thickness is 2.5 micrometers and volume is 90-95 cubic micrometers
Concentration of rbc in blood
5200000 in male and 4700000 in female (-/+300000)
Quantity of hemoglobin in blood
rbc can concentrate hemoglobin in their cell upto 34g/100ml
When hematocrit and the quantity of hemoglobin in each respective cell in normal, men have 15g hemoglobin /100ml and 14 for women
Quantity of hemoglobin in connection with O2
each gram of hemoglobin can combine with 1.34 ml of O2
Which means 20milimleters of oxygen can be carried with hemoglobin in 100milileetrs of blood and 19 for woman
Production of rbc
Early embryonic stage it is produced in yolk sac, middle trimester of gestation it is produced in liver and also in spleen and lymph nodes, last month of gestation and after birth to is made in bone marrow
What bones stop making rbc after 20 and except
Long bones except proximal part of humeri and tibiae all long bone marrow stops making rbc cause it becomes fatty
What bone marrow produce rbc aftef 20
Bone marrow of membranous bone like sternum, ribs , vertebra, ilia
Multipotential hematopoietic stem cells
the blood cells originate in the home marrow from one kind of cells which are multipotential hematopoietic stem cells
Committed stem cells ?
Cells reproduced from MHSCm differentiate to form other type of cells, their intermediate stage cells are exactly like multipotential stem cells, even though they are committed to a particular line of cells they are called committed stem cells
Growth inducers
growth and reproduction of committed stem cells are controlled by proteins called growth inducers
Example of growth inducers
interleukin-3
Differentiation inducers
only growth and reproduction is controlled by growth inducers but differentiation is controlled by differentiation inducers. Which differentiate only one type of committed stem cells
Genesis of rbc
proerythoblast Basophil erythroblast Polychromatophil erythroblast Orthrochromatic erthroblast Reticulocyte Mature erythroblast
Tissue oxygenation describe
the conditions which decrease the amount of oxygen transported to tissues increases the rate of RBC productions
Eg of tissue oxegenation
people who are anemic or destruction of major part of bone marrow due to xray therapy
Or people living in High altitude areas
People who have prolonged cardiac failure of lung diseases
Any tissue hypoxia case
Stimulus for rbc profuction is a circulating hormone called
erythropoietin, a glycoprotein with a molecular weight 34k
where are 90% of erythropoietin are formed
mainly in the kidneys and the rest are formed in liver
studies shows the erythropoietin is made in what cellsf
fibroblast like interstitial cells surrounding the tubules in cortex and outer medulla . renal epithelial cells also produce erythropoietin.
renal tissue hypoxia leads to?
increases tissue level of hypoxia induced factor-1 which serves as a transcription factor for a large number of hypoxia induced genes that includes erythropoietin gene.
explain briefly erythropoietin synthesis from the gene?
hypoxia induced factor binds to hypoxia response element, inducting transcription of messenger RNA and ultimately making erythropoietin.