関連ワード:  function of vena cava class 10    function of superior vena cava class 10    function of inferior vena cava class 10    function of vena cava in heart class 10    function of vena cava in kidney class 10    function of vena cava in excretory system class 10    function of vena cava from lower body class 10    function of vena cava from upper body class 10    function of vena cava from upper body in heart class 10    what is function of vena cava