Anaemia Flashcards
(99 cards)
What is anaemia
Decrease in RBC to a level that’s insufficient for respiration
Or decrease in O2 carrying capacity of blood
Decrease in the Hb conc, to a level where O2 delivery becomes compromised
When does O2 delivery become compromised in adult Male and female
When Hb conc is less than 13g/DL for male
12g/dL for women
When does O2 delivery become compromised for children
When Hb is less than 12g/dL (4-16 yrs)
11g/dL (30days- 6yrs)
13..5g/dL (0-30days)
What volume of O2 does 1g of Hb bind
1.34ml of O2
If the Hb conc ie 15g/dL , what’s the volume of O2 that can be carried
1.34 (for 1g of Hb) X 15
= 20ml
What is oxygen tension
The amount of O2 present in 100ml of blood
What is the normal O2 tension
20ml. (1.34 X 15)
What happens to O2 tension with reduction in Hb concentration
Reduces
What’s the partial pressure of O2 when the O2 tension is 20%
100mmHg
What’s the normal Hb conc, O2 tension and partial pressure in 100ml of blood
Hb conc: 15g/dL
O2 tension : 20 volume %
Partial pressure of O2: 100mmHg
What is the partial pressure of O2 in blood if the O2 tension falls from 20-15 volume%
It falls from 100mmHg to 40mmHg
When the O2 tension in the artery is 20volume% whats the O2 tension in the veins
15volume%
What’s the areterovenous O2 difference
5volume%
In every 100ml of blood, how much O2 is given to tissue and how much is retained
5volume% is given to tissue and 15volume% is retained
In every 100 ML of blood how much oxygen is given to the tissue and how much is it retained?
5ml is given to the tissue and 15ml is retained
What happens when an individual HB concentration is as low as 10 g/dL
The arterial partial pressure would fallen lower than the Venous partial pressure of oxygen hence, the pression gradient that’s allows oxygen to be driven tissue is lost.
If the Hb conc is 10g/dL, that means the O2 tension is 13.4volume% (instead of the normal 20volume% from 15g/dL Hb)
What happens when the Hb conc, the O2 tension and the O2 PP all reduce
The body adapts and tries to find a way to get O2 to all the pets of the body
What are the 5 adaptations to anaemia
•Modulation Hb/O2 affinity
•CVS adaptive mechanism
•Redistribution of blood flow
•Widen arterovenous O2 difference (by reducing venous O2 tension below 15volume%)
What kind of carrier of O2 is Hb
A reversible carrier
Binds to O2 at high O2PP but readily parts at low O2PP
What is high O2 affinity Hb
An abnormal Hb that has excessive affinity for O2
Complex with O2 at high or low PP ma don’t part , hence there could be Hb conc, but low O2 for tissues
What is Low O2 affinity Hb
An abnormality where the Hb has excessively low affinity for O2 hence only binds under excessively high PP of O2
The little O2 they have is delivered to tissues but it’s not enough
What happens to the affinity of O2 for Hb in anemia
Reduced
What pathway does RBC use to make ATP under normal conditions
Glycolytic pathway (Embden-meyerhof)
G3P—1,3DPG—3PG
What happens to O2 when it complexed with Hb
Emits a proton (to be acidic, hence in the absence of enough O2, the cytoplasm is alkaline)