Which one of the following is the manifestation of a "negative G"?
The options A, B, and C are the effects of positive "G". Gravitational force (Positive(+) G) would cause pooling of blood in the veins of lower extremities, causing an increase in hydrostatic pressure in the lower limb veins. Also, this pooling will decrease the venous return to the hea, and the Cardiac output will decrease. It will also lead to decrease in the blood flow and perfusion pressure in the cerebral vessels, resulting in a "black out" (failure of vision followed by unconsciousness). Negative (-) "G" will have the opposite effects. Blood will be shifted headword; there would be an increased cardiac output and a rise in cerebral aerial pressure. Congestion of retinal blood vessels and mental confusion will cause a "redout".
The hydrostatic pressure in veins of lower limb increases
The cardiac output decreases
Black out occurs
The cerebral aerial pressure rises
Circulation