循環器

1. Origins, structure, and basic meaning

• Structure: 循環器, read じゅんかんき, refers to circulatory organs or the circulatory system.
• Basic usage: 心臓や血管などの循環器 names body structures, whereas 循環器科 is the hospital department treating that system.

2. Common pitfalls and similar expressions

• Body system and 循環器科
  • Adding 科 changes the referent from organs or a system to a clinical department, naturally rendered as cardiology.