# In a resting person, how many O2 molecules attached to each hemoglobin molecule on average in blood and in pulmonary arteries?How many attach in blood in the pulmonary veins? Pulmonary System.

dano7744 | Certified Educator

Erythrocyes (red blood cells) carry the hemogoblin molecule. Oxygen is transported on the hemoglobin molecule. An average hemoglobin for an adult male is approximately 12 grams/dl.

All blood has hemoglobin and therefore some oxygen content but the arterial system has a higher percentage of hemoglobin compared to the venous system.  In other words, the number of oxygen molecules is much higher in an artery than in a vein. The one exception to this are the pulmonary arteries and veins. Pulmonary arteries carry oxygen poor blood to the lungs from the right ventricle. Pulmonary veins carry oxygen rich blood (because the blood just left the lungs) to the left atrium.

In a relatively healthy individual, the arterial blood is said to be saturated with oxygen at around 97-100 %. Again, a venous sample would be much lower than that.

ashkuehn | Student

I think I will add to the previous answer.  Since you are talking about O2 molecules maybe you are after this information.  Each hemoglobin molecule has 4 sites on it that are able to transport oxygen molecules.

The actual amount of hemoglobin does not change in different parts of the circulatory system, what does is the amount of oxygen.

As an aside oxygen is transported in blood in two ways.  One being bonded to hemoglobin and also dissolved in the plasma.  the measurement Partial pressure of oxygen (PaO2) is the amount dissolved and the Saturation of oxygen (SO2) is the percentage of hemoglobin bonding sites that have oxygen currently attached.

Thus the oxygen content equation

CO2=hg*1.34*SO2+PO2*0.0031