Blood pressure within the vena cava increases during head-out water immersion because:

Question

Accepted Answer

a positive pressure is applied to the lower body, which compresses large veins, so increasing the volume of blood in the vena cava in the chest.

Answer

atrial natriuretic peptide is released, which causes contraction of the vena cava.

Answer

changes in the pattern of breathing lead to increases in pulmonary vascular resistance.

Answer

water is absorbed via the skin, so increasing total blood volume.

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