choroid

…one of the membranes that make up the eyeball. Located between the outer cornea (a collective term for the cornea and sclera) and the inner retina, it is divided into the anterior uvea (iris) and ciliary body, and the posterior uvea (choroid). It is a tissue rich in blood vessels that controls nutrition and metabolism within the eye, but the iris and ciliary body are also involved in light response and accommodation, which dilates and constricts the pupil, through the action of the muscles (internal ocular muscles) that are distributed throughout the eye. …

*Some of the terminology that mentions "choroid" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…眼球をつくる膜のひとつ。外側の強角膜(角膜と強膜を総称していう)と内側の網膜の間にあり，前部ぶどう膜の虹彩iris，毛様体ciliary bodyと，後部ぶどう膜の脈絡膜choroidとに分けられる。血管に富む組織で眼内の栄養や代謝をつかさどるが，虹彩や毛様体はさらに分布する筋肉(眼筋のうちの内眼筋)の作用によって，瞳孔を広げたり縮めたりする対光反応や調節にも関与する。…

※「choroid」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報