Your veins have a system of valves that work to keep the back flow of blood from returning the areas where blood has already passed. Once the left ventricle of the heart has finished contracting, gravity will tend to pull blood downward. When this happens, blood pushes back the valves, forcing them closed. The valves will reopen when the force of the blood being pumped exceeds the amount of force opposing the valves.
As a side note, valves work to allow flow of a fluid in one direction only. Sphincters (such as your cardiac sphincter in your stomach) allow for fluid or in the stomach's case, a bolus, to enter and exit your stomach, allowing an individual to vomit. Rats and horses do not have cardiac sphincters, thus making it impossible for them to vomit.
The muscles in your legs help transport blood back to your heart. The veins in your legs also have valves to help this process and prevent blood from flowing back down towards your feet.
The muscles in your legs help transport blood back to your heart. The veins in your legs also have valves to help this process and prevent blood from flowing back down towards your feet.
Valves, allown blood through in one direction when the pressure builds up but close when pressure is applied in the opposite direction.
the french
no. he kept moving in his childhood.
A container in which items contaminated by blood are kept
The energy in a moving object is kept in its kinetic energy store. This energy is related to the object's mass and its velocity.
inertia
its not
'''by the heart <3'''
blood is kept in different conditions whole blood is kept in pack with anticoagulant (ACD) at 2 to 8 degrees. While other blood componets like fresh frozen plasma is kept in a very cold environment
I think its by blood type cause if they mix diff. blood types, it should not be given to a person