・「水晶体上皮の基底膜が発達したもの 」（船戸和弥のHP）
・「ヒトの生体内でもっとも厚い基底膜の一つ 」（「細胞基底膜としての水晶体囊の役割 」）
・「The lens capsule is the thickest basement membrane in the body.」（Wikipedia）
注意）厚さに関しては資料によって違いが見られ、後面のものを中央部は薄く、縁部
を厚くしているイラストを掲載しているサイトも見られる。
「細胞基底膜としての水晶体囊の役割 」」には以下のような解説文が見られる。
「病原体などが水晶体内部に侵入することを防ぐ一 方，分子量の小さいグルコース，酸素や
二酸化炭素などは自由に透過できるが，蛋白質などは分子量によって選 択的に透過すると
考えられている。」
以下は「Wikipedia」の解説文となる。
The lens capsule is a component of the globe of the eye. It is a clear elastic basement membrane composed of collagen IV, laminin etc. a quality that keeps it under constant tension. As a result, the lens naturally tends towards a rounder or more globular configuration, a shape it must assume for the eye to focus at a near distance. The lens capsule is the thickest basement membrane in the body.
Normally, the lens capsule serves as a diffusion barrier. It is permeable to low molecular weight compounds but restricts the movement of large colloidal particles.
【 語 句 】
・elastic： ・basement membrane： ・laminin： ・configuration：形状 ・assume：推測する、引き受ける ・diffusion barrier：拡散障壁 ・permeable：浸透性の ・molecular weight：分子量 ・colloidal particle：コロイド粒子
【Anatomy】
The lens capsule is a transparent membrane that surrounds the entire lens. The capsule is thinnest at the posterior pole with approximate thickness of 3.5μm. Average thickness at the equator is 7μm. Anterior pole thickness increases with age from 11-15μm. The thickest portion of is annular region surrounding the anterior pole. This will also increases with age (from 13.5-16μm). The ligaments suspending the lens form attachments in the equatorial area and more so just to the front and back of the equator. There are tens of thousands of these ligaments in a mouse lens and for the most part they appear to connect directly to the lens capsule.
As the lens grows throughout the life of most vertebrates the capsule is required to grow as well. Some ligament anchors have associated cells where they connect to the lens capsule with periodic cellular processes penetrating the capsule itself.
【 語 句 】
・equator：赤道 ・annular region：環状域 ・vertebrate：脊椎動物 ・periodic：間欠的な ・penetrate：貫く
【Function】
The capsule helps give the lens its more spherical shape in aquatic vertebrates such as fish and more ellipsoidal shape in land based vertebrates such as sheep. In humans the lens ellipsoid becomes more flattened with age. The capsule is the basement membrane for the epithelial cells at the front of the lens and the rapidly growing more flexible fiber cells of the back of the lens and below the epithelium at the front. Without the capsule substrate forming a tense support these cells lose their form as in the picture of a decapsulated sheep lens.
【 語 句 】
・spherical：球形の ・ellipsoidal：楕円体の ・epithelial cell：上皮細胞 ・substrate：基質
【Accommodation】
Main article: Accommodation (eye)
Normally, when ciliary muscles are in a relaxed state, the zonules will pull the capsule. Due to this zonular tension anterior lens surface is flatter resulting in more distant objects being in focus. When ciliary muscles contract, the zonular tension will reduce allowing lens to assume more spherical shape. This shape change increases the focusing power of the eye allowing closer objects to come into focus. The process of changing the lens's focusing power to see closer objects more clearly is known as accommodation.
【 語 句 】
・accomodation：視力調節 ・ciliary muscle：毛様体筋 ・zonules：毛様体小帯 ・contract：収縮する
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