noun
Anatomical term for a membranous valve, especially in the heart and veins.
心臓の弁膜が正常に機能しないと、血液が逆流することがある。
If the heart valves do not function properly, blood can flow backward.
弁 alone can mean 'valve' in a broader sense (e.g., 安全弁 safety valve), while 弁膜 specifically refers to membranous valves in the body.
Compound of 弁 (valve) and 膜 (membrane).