The upper chamber on each side is called the atrium.This is connected via a sealing valve to the larger, more powerful lower chamber, or ventricle.是什么意思_The upper chamber on each side is called the atrium.This is connected via a sealing valve to the larger, more powerful lower chamber, or ventricle.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句