a bodily organ that contracts

収縮する体の器官

a ring of muscle that contracts to close an opening

開口部を閉じるために収縮する筋肉の輪

any of several muscles that cause an attached structure to become tense or firm

付随する構造を緊張や硬直させる複数の筋肉のいずれか

a muscle that contracts without conscious control and found in walls of internal organs such as stomach and intestine and bladder and blood vessels (excluding the heart)

意識的な制御なしに収縮する筋肉。胃や腸・膀胱・血管などの内臓の壁に見られる（心臓を除く）

one of the small muscles of the eye that serve to rotate the eyeball

眼球を回転させる役割をする小さな眼の筋肉の一つ。

any of various straight muscles

様々な直筋のいずれか

an elongated contractile cell that forms the muscles of the body

体の筋肉を構成する伸長強縮可能な細胞