Which one is main source of elastic resistance of the lungs?()
A. The surface tension within the alveoli
B. The elastic recoil of the lung tissues
C. Airway resistance
D. Inertial resistance
E. Viscous resistance
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The vital humoral factor regulating the production of RBC is ____.()
Androgen
B. Growth hormone
C. Thyroid hormone
D. Estrogen
Erythropoietin
The type of blood is decided by ____.()
A. The type of receptor on RBC membrane
B. The type of antigen on RBC membrane
C. The type of antibody on RBC membrane
D. The type of antigen in plasma
E. The type of antibody in plasma
Initial length of skeletal muscle is determined by __.()
A. passive tension
B. preload
C. afterload
D. the difference between the preload and the afterload
E. the summation of the preload and the afterload
In the absolute refractory period, the excitability of tissues is()
A. zero
B. infinity
C. greater than the normal
D. less than the normal
E. equal to the normal
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