Which of the following may be the effect of positive 'g' acceleratory force on the body of ator:September 2011
As. D: Pooling of blood in lower bodyDuring exposure to positive 'g' for the first few seconds, blood is thrown into the lower pas of the body, therefore, venous return to hea decreases resulting in fall in cardiac output and systolic BPAngular acceleration or centrifugal force.If a fighter pilot is diving at the rate of 450 miles an hour and pulls out of this dive on the arc of a circle having a radius of about one-half mile, centrifugal force will press his body down onto the seat of the plane with a force which will be slightly more than five times the force of gravity.Thus if the flyer's weight is 180 lbs., the force of his body against the seat of the plane would equal more than 900 lbs.His arms would be so heavy that he would be unable to lift them.The blood would have a weight five times its normal value.This would make it difficult for the Hea to pump an adequate amount of blood to the brain.Blood would, therefore, tend to drain out of, the upper pa of the body and become pooled in the abdomen and the legs, and the ator would suffer from cerebral ischemia.The first effect of this ischemia would be a blurring and graying of the vision as though a semi-transparent cuain were lowered before the eyes.This would be accompanied by a narrowing of the visual field.If the centrifugal force on the body is continued or increased, the ator will "black out," that is, he will suffer a complete loss of vision and finally will lose consciousness.The extent of the physiological changes produced depends upon both the magnitude and duration of the centrifugal force applied to the body.
Increased cardiac output
Initial rise and then fall of blood pressure
Thrombocytopenia
Pooling of blood in lower body