Blood pressure? what happens? Give em a simple explanation?

It is highest immediately after the heart because the aorta is a muscular artery that initially expands after cardiac contraction but then after the heart relaxes it returns to its initial, smaller diameter. However, venous blood is not completely without pressure because there is still a higher pressure differential on the pre capillary side than the post, venous side. And the pressure in the vascular system is the lowest in the right atrium. Muscle massage/contraction does help move blood, particularly in the legs where gravity has the greatest effect, but mainly the fact that pressure is essentially zero in the right side of the heart but the mean systemic filling pressure for 5L of blood is 7mmHg is what causes the blood to keep moving and avoid venous stasis.

Blood pressure is highest in the arteries when the heart contracts (systole) and lessens when the heart relaxes (diastole). This is when the 2 measurements are made, such as 115/70. Pressure declines rapidly as the blood approaches the capillary bed, and there is virtually no blood pressure in the veins (we rely on muscle massage to move the blood).