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The lens is located towards the front part of the vertebrate eye, called the anterior segment, which includes the cornea and iris positioned in front of the lens. The lens is held in place by the suspensory ligaments (Zonule of Zinn), [1] attaching the lens at its equator to the rest of the eye [2] [3] through the ciliary body.
Sheep eye lens capsule with ligaments attached. The capsule is lifting off the lens showing cell fiber ends beneath. Microscope image of lens capsule in relation to lens cell types. The lens capsule is a component of the globe of the eye. [1] It is a clear elastic basement membrane similar in composition to other basement membranes in the body.
The ciliary body is a part of the eye that includes the ciliary muscle, which controls the shape of the lens, and the ciliary epithelium, which produces the aqueous humor. The aqueous humor is produced in the non-pigmented portion of the ciliary body. [ 1 ]
The eukaryotic cell cycle consists of four distinct phases: G 1 phase, S phase (synthesis), G 2 phase (collectively known as interphase) and M phase (mitosis and cytokinesis). M phase is itself composed of two tightly coupled processes: mitosis, in which the cell's nucleus divides, and cytokinesis, in which the cell's cytoplasm and cell membrane divides forming two daughter cells.
When the ciliary muscle contracts, it pulls itself forward and moves the frontal region toward the axis of the eye. This releases the tension on the lens caused by the zonular fibers (fibers that hold or flatten the lens). This release of tension of the zonular fibers causes the lens to become more spherical, adapting to short range focus.
[5] [6] Furthermore, Hensen's cells are also able to regenerate the damaged hair cells in some vertebrates; they undergo phagocytosis to eject the dead or injured hair cells, and reproduce both new hair cells and supporting cells into the cell cycle. One of the reasons is that the supporting cells are differentiated by the embryonic hair cells ...
Binocular eyepieces usually consist of three or more lens elements in two or more groups. The lens furthest from the viewer's eye is called the field lens or objective lens and that closest to the eye the eye lens or ocular lens. The most common Kellner configuration is that invented in 1849 by Carl Kellner. In this arrangement, the eye lens is ...
Visual phototransduction is the sensory transduction process of the visual system by which light is detected by photoreceptor cells (rods and cones) in the vertebrate retina.A photon is absorbed by a retinal chromophore (each bound to an opsin), which initiates a signal cascade through several intermediate cells, then through the retinal ganglion cells (RGCs) comprising the optic nerve.