Respiration IV Flashcards
The amount of dissolved gas carried by the blood is directly proportional to […], according to […] Law.
the partial pressure of the gas, according to Henry’s Law.
How much O2 is dissolved in 100 ml of plasma? What is its partial pressure?
0.3 ml of O2 at a partial pressure of 100 Hg.
How does the amount of oxygen dissolved in plasma compare to the oxygen requirements of cells?
There is around 0.3 ml of O2 dissolved in 100 ml of plasma, but the O2 consumption of the body is about 300 ml per minute. Thus, only the O2 transported in plasma is not sufficient to meet our needs.
Hemoglobin allows the blood to take up […] times as much oxygen as plasma
65
Hemoglobin constitutes […] of the total weight of red blood cells.
1/3
Describe the structure of hemoglobin.
Each molecule has 4 subunits. Each subunit has a heme joined to a globin. Heme contains an Fe2+ ion that can bind 1 molecule of O2.
Write the formula for the rapid and reversible combination of hemoglobin with oxygen.
Hb + O2 <-> HbO2
The total amount of O2 in arterial blood is about […] vol. %
20
What is included and not included in the calculation of PO2 of the blood?
The O2 that is bound to hemoglobin does not contribute to the partial pressure of O2 in the blood. Only molecules physically dissolved in the blood plasma are responsible for PO2.
What is the O2 dissociation curve?
It depicts the amount of O2 carried by hemoglobin for a given partial pressure of oxygen in the plasma.
Draw and describe the shape of the O2 dissociation curve.
The curve is flat at high values of PO2 (80-100 mm Hg) and is steep at low values of PO2 (below 60 mm Hg).
Explain the reason behind the shape of the O2 dissociation curve
Hemoglobin provides an automatic mechanism that matches the oxygen supply to the oxygen needs. If it’s needed, it lets it go. If it’s not needed, it transports it to where it is needed.
At low values of PO2, as seen in the peripheral tissues, a small drop in PO2 unloads a lot of O2 from Hb to the tissue.
What is myoglobin and where is it found?
Myoglobin is another oxygen carrier like hemoglobin. It is fund in muscle cells.
The affinity of hemoglobin for O2 is determined by its […]
quaternary structure
What is cooperative binding in hemoglobin?
The combination of the first heme with Hb in a hemoglobin molecule increases the affinity of the second heme for O2.