valve in veins造句

• The valves in veins were described by Jacques Dubois, but their true function was later discovered by William Harvey.
• Mean blood pressure decreases as the hydrostatic forces ( e . g ., during standing ), and valves in veins, breathing, and pumping from contraction of skeletal muscles also influence blood pressure in veins.
• In nature there are valves, for example one-way valves in veins controlling the blood circulation, and heart valves controlling the flow of blood in the chambers of the heart and maintaining the correct pumping action.
• The 16th and 17th centuries also witnessed significant advances in the understanding of the circulatory system, as the purpose of valves in veins was identified, the left-to-right ventricle flow of blood through the circulatory system was described, and the hepatic veins were identified as a separate portion of the circulatory system.