lens induction in camera-type eye

Definition

Target type: biologicalprocess

Signaling at short range between the head ectoderm and the optic vesicle that results in the head ectoderm forming a lens. [GOC:dph, ISBN:0878932437]

Lens induction in camera-type eyes is a complex process that involves a series of interactions between the optic vesicle, a protrusion from the developing brain, and the surface ectoderm, the outermost layer of cells in the embryo. This interaction leads to the formation of the lens, a transparent structure that focuses light onto the retina.

Here's a detailed breakdown of the process:

1. **Optic Vesicle Formation:** The first step in lens induction is the formation of the optic vesicle, an outgrowth from the developing brain. The optic vesicle is composed of a single layer of epithelial cells and is destined to become the retina.

2. **Optic Vesicle Contact with Surface Ectoderm:** The optic vesicle makes contact with the surface ectoderm, the outermost layer of cells in the embryo. This contact triggers a cascade of signaling events that will ultimately lead to the formation of the lens.

3. **Lens Placode Formation:** The surface ectoderm, upon contact with the optic vesicle, begins to thicken and invaginate, forming a cup-shaped structure called the lens placode. This thickening is driven by the expression of genes, like Pax6, that promote cell proliferation and differentiation.

4. **Lens Vesicle Formation:** The lens placode continues to invaginate, eventually forming a hollow sphere known as the lens vesicle. This vesicle is filled with a fluid called the lens humor and is separated from the surface ectoderm by a thin layer of cells called the lens epithelium.

5. **Lens Fiber Differentiation:** The cells in the lens vesicle undergo a process called lens fiber differentiation. These cells elongate, lose their nuclei and organelles, and become filled with a protein called crystallin. Crystallin proteins are highly transparent and allow light to pass through the lens with minimal scattering.

6. **Lens Capsule Formation:** A thin, elastic membrane called the lens capsule forms around the lens fibers, providing structural support. The lens capsule is composed of collagen and other extracellular matrix proteins.

7. **Final Lens Structure:** The lens, now fully formed, is a transparent structure with a capsule surrounding a central core of lens fibers. It is attached to the retina by the zonules, fine fibers that allow the lens to change shape for accommodation, the process of focusing on objects at different distances.

This complex interplay of signaling pathways, gene expression, and cellular differentiation ensures the precise formation of a functional lens, essential for vision in camera-type eyes.'
"

Proteins (3)

Compounds (79)