Ortho: straight. Stasis: standing. The mean blood pressure does not change, thus allowing for the person
not to faint when standing up. When standing up, the blood flows out of the chest, which then allows
for the right atrial pressure to drop. The baroreceptor effect makes it so that the contractility increases
and the constriction of the arteries. During extended period of standing, pumping the calf muscles
allows for the blood to be forced back into the heart, to restore the blood pressure.
Venous valves and muscle pumps shifting blood and preventing them from back flowing. Venous
pressure while standing is about 80mmHg at the bottom of the foot. Plasma volume is pumped out from
the cell junctions, the longer one stands, the more the fluid leaks out. As such, 15 minutes of standing
would lead to nearly 700mL of volume lost. The muscle pumps also lower the venous pressure in the
veins and capillaries. Valvular incompetence leads to venous hypertension.
Heart rates maxed out at 220 minus age. Stroke volume increases until it becomes too fast to
completely fill. Cardiac output is increased nearly linearly. MAP = CO x TPR, the total peri