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Hemoglobin increases the oxygen-carrying capacity of blood by about 40-fold, [62] with the ability of hemoglobin to carry oxygen influenced by the partial pressure of oxygen in the local environment, a relationship described in the oxygen–hemoglobin dissociation curve. When the ability of hemoglobin to carry oxygen is degraded, a hypoxic ...
Hemoglobin has an oxygen-binding capacity of 1.34 mL of O 2 per gram, [6] which increases the total blood oxygen capacity seventy-fold compared to dissolved oxygen in blood plasma alone. [7] The mammalian hemoglobin molecule can bind and transport up to four oxygen molecules. [8] Hemoglobin also transports other gases.
While there is general agreement that an arterial blood gas measurement which shows that the partial pressure of oxygen is lower than normal constitutes hypoxemia, [5] [6] [7] there is less agreement concerning whether the oxygen content of blood is relevant in determining hypoxemia. This definition would include oxygen carried by hemoglobin ...
Expressed as a percentage, the oxygen saturation is the ratio of the amount of oxygen bound to the hemoglobin, to the oxygen-carrying capacity of the hemoglobin. The oxygen-carrying capacity of hemoglobin is determined by the type of hemoglobin present in the blood. The amount of oxygen bound to the hemoglobin at any time is related, in large ...
Venous oxygen saturation (SvO 2) is the percentage of oxygenated hemoglobin returning to the right side of the heart. It can be measured to see if oxygen delivery meets the tissues' demands. SvO 2 typically varies between 60% and 80%. [9] A lower value indicates that the body is in lack of oxygen, and ischemic diseases occur.
The production of red blood cells (or erythropoeisis) in the body is regulated by erythropoietin, which is a protein produced by the kidneys in response to poor oxygen delivery. [14] As a result, more erythropoeitin is produced to encourage red blood cell production and increase oxygen-carrying capacity.
A strict but broad definition is an absolute decrease in red blood cell mass, [61] however, a broader definition is a lowered ability of the blood to carry oxygen. [62] An operational definition is a decrease in whole-blood hemoglobin concentration of more than 2 standard deviations below the mean of an age- and sex-matched reference range. [63]
Hemoglobin has an oxygen binding capacity between 1.36 and 1.40 ml O 2 per gram hemoglobin, [23] which increases the total blood oxygen capacity seventyfold, [24] compared to if oxygen solely were carried by its solubility of 0.03 ml O 2 per liter blood per mm Hg partial pressure of oxygen (about 100 mm Hg in arteries).