The ciliary body and the suspensory ligaments (also known as zonules or zonule of Zinn) play crucial roles in the eye's ability to focus light properly onto the retina.
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Ciliary Body: The ciliary body is a circular structure located behind the iris and is part of the uveal tract of the eye. It has two main functions:
- Accommodation: The ciliary body contains smooth muscles (ciliary muscles) that control the shape of the lens. When the ciliary muscles contract, the tension on the suspensory ligaments is reduced, allowing the lens to become more rounded. This increased curvature is necessary for focusing on nearby objects. When the ciliary muscles relax, the ligaments pull on the lens, flattening it for focusing on distant objects.
- Aqueous Humor Production: The ciliary body also produces aqueous humor, the fluid that fills the anterior chamber of the eye, helping maintain intraocular pressure and providing nutrients to nearby structures.
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Suspensory Ligaments (Zonules): The suspensory ligaments attach the ciliary body to the lens and play a vital role in maintaining its position. Their functions include:
- Support of the Lens: The zonules hold the lens in place, ensuring that it stays properly positioned in the eye during all movements.
- Transmission of Force: When the ciliary muscles contract or relax, the suspensory ligaments either tighten or loosen. This action changes the shape of the lens, facilitating the accommodation process for near and far vision.
In summary, the ciliary body and suspensory ligaments work together to adjust the shape of the lens, allowing the eye to focus on objects at varying distances effectively.
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