The crystalline lens is developed from the surface
ectoderm as below :
Primary lens fibres. The cells of posterior wall of lens vesicle elongate rapidly to form the primary lens
fibres which obliterate the cavity of lens vesicle. The primary..lens fibres are formed upto 3rd month of gestation and are preserved as the compact core of
lens, known as embryonic nucleus (Fig. 1.11).
Secondary lens fibres are formed from equatorial cells of anterior epithelium which remain active through out life. Since the secondary lens fibres are laid down
concentrically, the lens on section has a laminated appearance. Depending upon the period of
development, the secondary lens fibres are named as below :
ectoderm as below :
Primary lens fibres. The cells of posterior wall of lens vesicle elongate rapidly to form the primary lens
fibres which obliterate the cavity of lens vesicle. The primary..lens fibres are formed upto 3rd month of gestation and are preserved as the compact core of
lens, known as embryonic nucleus (Fig. 1.11).
 |
| Development of the crystalline lens. |
Secondary lens fibres are formed from equatorial cells of anterior epithelium which remain active through out life. Since the secondary lens fibres are laid down
concentrically, the lens on section has a laminated appearance. Depending upon the period of
development, the secondary lens fibres are named as below :
- Fetal nucleus (3rd to 8th month),
- Infantile nucleus (last weeks of fetal life to
puberty), - Adult nucleus (after puberty), and
- Cortex (superficial lens fibres of adult lens)
Lens capsule is a true basement membrane produced
by the lens epithelium on its external aspect.
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