18 Feb 2016 | 258,249 Views. You may not even associate this with your health, yet it can make a life or death difference. Ignore or defy it, and your risk of death before your 65th birthday jumps 25 percent. Here's the big takeaway message to tell your body for health and longevity.
1 Veins have valves which maintain the unidirectional flow of blood, even against gravity. 2  Since the venous pressure is low (7 mm Hg) the valves are of utmost value in the venous return. However, the valves are absent in: 3  The veins of less than 2 mm diameter.  The venae cavae.
A heart valve normally allows blood to flow in only one direction through the heart. The four valves commonly represented in a mammalian heart determine the pathway of blood flow through the heart.A heart valve opens or closes incumbent on differential blood pressure on each side.The four main valves in the heart are: heart valve normally allows blood to flow in only one direction through the heart. The four valves commonly represented in a mammalian heart determine the pathway of blood flow through the heart. A heart valve opens or closes incumbent on differential blood pressure on each side. The four main valves in the heart are: