Book of the Ten Treatises of the Eye the sclera, a thick, hard membrane which protects the inner parts of the nerves from injury. The chorioid, a thin and soft structure filled with veins and arteries, follows next and provides nourishment to the overall structure. Finally, the retina transmits nutrients to the lenses themselves. Hunayn then presents the system responsible for protecting the eye. From the outermost level, these are the conjunctiva, cornea, and uvea. While both the conjuctiva and cornea provide protection with minimizing hindrance to the lenses, the uvea has an extra function of concentrating the pneuma exiting out of the eye to prevent it from
Parasympathetic root of ciliary ganglion short ciliary nerves. These nerves enter the posterior aspect of the eyeball to innervate the sphincter pupillae and ciliaris muscles. The "sphincter pupillae" constricts the iris. The "ciliaris" muscle changes the shape of the lens, allowing the eye to focus on nearby objects (accommodation). Neither of these muscles is under voluntary control. Parasympathetic root of ciliary ganglion The parasympathetic root of ciliary ganglion provides parasympathetic innervation to the ciliary ganglion. The ciliary ganglion is a "parasympathetic" ganglion. Incoming parasympathetic nerve fibers form synapses with the dendrites of nerve cells within the ganglion. However, the ciliary ganglion is not simply a