Objective 33: Skeletal muscle contraction role in venous valves in returning blood to heart

Figure 18.7 from my textbook I think is a good representation for objective 33 because it basically spells it out.  I remember going through this in lecture. We talked about during exercise, muscles contract. The intramuscular pressure exerted on the veins by the surrounding muscle pushes blood through the one-way valves of the veins, returning it to the heart. The pumping action keeps blood from pooling in the lower limbs, and people that stand still for long periods of time can experience little venous return to the heart and low blood pressure leading to dizziness or fainting.