The chambers are separated by valves that prevent the backflow of blood as it moves through the heart.

这些腔室由瓣膜隔开，防止血液在心脏中动。

The ureters insert into the bladder at the ureterovesical junction at a sideways angle so that when the bladder becomes full, it compresses the openings to the ureters preventing the backflow of urine.

输尿管在输尿管-膀胱交界处倾斜插入膀胱；这样一来，当膀胱充盈，输尿管开口受压，从而阻止尿液反。