Question

Choose between the two options to answer the question specified in the brackets for the following.
An example is illustrated.
Example: Corolla or calyx (which is the outer whorl?) Answer: Calyx.
Sclerotic layer or choroid layer (which of the two forms the iris?)

Answer 1

It is a dense network of blood vessels and pigmented stroma between the retina and the sclera. It is composed of white fibrous tissue intermixed with fine elastic fibers and corpuscles of flattened connective-tissue. These fibers are grouped in bundles.

Complete answer:
The sclerotic layer forms the outermost layer of the eye and protects the eye. The choroid layer forms the Iris. Sclerotic or sclera is the external or outermost layer of the eye. It is composed of dense connective tissue and contains collagen and elastin fibers. It maintains the shape of the eye and also protects it. The anterior portion of the sclera is called the cornea which absorbs oxygen from the air and helps to focus the light rays entering the eye.

Additional information: The choroid supplies the external retina with supplements and keeps up the temperature and volume of the eye. The choroidal circulation, which represents 85% of the total bloodstream in the eye, is a high-stream framework with moderately low oxygen content. The choroid flow is controlled predominantly by sympathetic innervation and is considered not to be autoregulated. This absence of autoregulation makes the choroid more dependent on the ocular perfusion pressure. The white sclerotic coat proceeds around the eye, the vast majority of which are not visible while the eyeball is situated in its attachment inside the face/skull. The primary region of the eye that isn't secured by the region is the front part of the eye that is protected by the transparent cornea instead.

Note: The choroidal stroma is relatively proportional more thinner in rodents than in humans, and it contains dendritic melanocytes, fibroblasts, and mast cells. The choroidal vasculature is provided by the long and short posterior ciliary arteries and the anterior ciliary arteries; drainage occurs via the vortex vessels. The sclerotic coat is provided by numerous nerves and vessels that go through the posterior scleral foramen, the gap in the sclerotic coat formed by the optic nerve.