Haemoglobin Flashcards
How much haemoglobin are in men and women?
Males = 160g/L Females = 150g/L
How much oxygen can haemoglobin bind?
Each gram of haemoglobin can bind 1.34mL of oxygen
How much oxygen can be carried in blood?
20mL of oxygen can be carried in 100mL of blood (in women, 19mL)
Why do men have more Hb?
Due to their higher levels of testosterone, which influences erythropoietin.
How is newborn Hb different from children and adult Hb?
Newborn have higher Hb due to their need for more Hb in the foetus.
Fetal Hb also has a higher affinity for oxygen.
Children have lower Hb.
Describe is the Hb content in different parts of the body.
Venous blood has the same amount of Hb as arterial blood.
Venous blood from the spleen is lower, due to the fact that RBC’s are destroyed here.
Blood from bone marrow has more Hb since its here that RBC are produced.
Renal vein has higher Hb (same as in skin) because water has been filtered from the blood therefore the relative proportion of blood cells is higher.
Portal vein has lower Hb because it takes water from the intestines, therefore a lower relative concentration of blood cells.
How is Hb regulated?
Tissue oxygenation is the most essential regulator.
Any condition that causes oxygen levels to decrease will create a crystal that ruptures cell membranes of capillaries.
–> This causes pathology
What is erythropoietin?
Hormone produced in kidney (90%) and liver (10%). Stimulates erythropoiesis (production of erythrocytes).
What is sickle cell anaemia?
An amino acid substitution occurs in one of the beta chains.
When exposed to oxygen, will create a crystal which will rupture cell membranes of capillaries.
Explain the Hb binding of oxygen.
The most important feature of Hb is that it can combine loosely with reversibly with oxygen.
Binding of oxygen to Hb will displace carbon dioxide from the blood (Haldene effect).
When oxygen binds to Hb it will cause Hb to become a stronger acid.
This displaces carbon dioxide in the following ways:
- The more acidic Hb has less tendency to combine with carbon dioxide to form carbamino-haemoglobin, thus displacing much of the carbon dioxide that is in the form of carbamino.
- The increased acidity causes release of hydrogen ions.
- These bind bicarbonate-ions to form carbonic acid, this dissociates into water and carbon dioxide that is then released into the air.
What is the role of Hb in oxygen transport?
97% of the transported oxygen is bound to Hb.
3% is dissolved in the water portion of blood plasma.
The presence of Hb allows the blood to transport 30-100 times more oxygen as if it were dissolved in the water of blood.
What pressure conditions are required for binding of oxygen to Hb?
When oxygen pressure is higher (as in the pulmonary capillaries) oxygen binds with Hb.
When oxygen pressure is lower (as in the tissue capillaries) oxygen is released from Hb.
The total amount of oxygen bound with haemoglobin in normal arterial blood, which is 97% saturated, is about 19.4 mL per 100mL of blood.
–> Which is 20%.
What is the Hb distribution curve?
If the blood gets more acidic, the oxygen haemoglobin dissociation curve will shift.
Factors that will shift the curve to the right (less Hb saturation):
Increased concentration of carbon dioxide.
Increased blood temperature.
icnreased BPG concentration.
Decreased pH.
What is Met-Hb?
1% of Hb
Fe2+ –> Fe3+
Cannot bind oxygen :(
What is haemoglobinometry?
Tells us about the oxygen transporting capacity of blood.
Hb can change if a patient is sick (e.g. anaemia).
Low Hb can indicate that transfusion might be necessary.
