A shift of posture from supine to upright posture is associated with cardiovascular adjustments. Which of the following is NOT true in this context: (A) Rise in central venous pressure, (B) Rise in heart rate, (C) Decrease in cardiac output, (D) Decrease in stroke volume
Answer is A. Changes when position altered from standing/sitting to lying.
Immediate: The stroke volume, BP and cardiac output increases due to increased venous return and the increased CVP. Late: This stimulates the baroreceptors and the result is vasodilation, decreased heart rate, decreased cardiac contraction, decreased cardiac output and finally a decreased or normal BP.
Changes when position altered from lying to standing/sitting.
Immediate: The stroke volume, BP and cardiac output decreases due to decreased venous return and the decreased CVP. Late: This causes the baroreceptors to discharge less and the result is vasoconstriction, increased heart rate, increased cardiac contraction, increased cardiac output and finally an increased or normal BP.