One gram of hemoglobin when fully saturated can com-bine with and carry___ ml of oxygen.
Ans. b (1.39). (Ref. Ganong Physiology 21st ed. 671)# Normal oxygen uptake is 250 mi/min# 1 gm of Hb carries 1.34 ml of oxygen# 02 dissociation curve is sigmoid in shape# The oxygen-hemoglobin dissociation curve, the curve relating percentage saturation of the O2-carrying power of hemoglobin to the P02, has a characteristic sigmoid shape due to the T-R interconversion.# When blood is equilibrated with 100% O2 (PO2 = 760 mm Hg), the normal hemoglobin becomes 100% saturated. When fully saturated, each gram of normal hemoglobin contains 1.39 mL of O2. However, blood normally contains small amounts of inactive hemoglobin derivatives, and the measured value in vivo is lower. The traditional figure is 1.34 mL of O2.# In vivo, the hemoglobin in the blood at the ends of the pulmonary capillaries is about 97.5% saturated with 02 (PO2 = 97 mm Hg). Because of a slight admixture with venous blood that bypasses the pulmonary capillaries (physiologic shunt), the hemoglobin in systemic arterial blood is only 97% saturated.# The arterial blood therefore contains a total of about 19.8 mL of 02 per dL: 0.29 mL in solution and 19.5 mL bound to hemoglobin. In venous blood at rest, the hemoglobin is 75% saturated and the total O2 content is about 15.2 mL/dL: 0.12 mL in solution and 15.1 mL bound to hemoglobin.# About 250 mL of O2 per minute is transported from the blood to the tissues at rest.Also remember;GAS CONTENT OF BLOODmL/dL of Blood Containing 15 g of HemoglobinArterial Blood (PO2 95 mm Hg;Venous blood (PO2 40 mm Hg;PCO2 40 mm Hg; Hb 97%PCO2 46 mm Hg; Hb 75%Saturated)Saturated) GasDissolvedCombinedDissolvedCombinedO20.2919.50.1215.1CO22.6246.42.9849.7N20.9800.980MYOGLOBIN# It is an iron-containing pigment found in skeletal muscle.# It resembles hemoglobin but binds 1 rather than 4 mol of O2 per mole.# Its dissociation curve is a rectangular hyperbola rather than a sigmoid curve. Because its curve is to the left of the hemoglobin curve, it takes up O2 from hemoglobin in the blood.# It releases O2 only at low PO2 values, but the PO2 in exercising muscle is close to zero.# The myoglobin content is greatest in muscles specialized for sustained contraction.# The muscle blood supply is compressed during such contractions, and myoglobin may provide 02 when blood flow is cut off.
0.39
1.39
13.9
139
Heart, Circulation, and Blood