In the standard industry communications reference model, Open Systems Interconnection (OSI), the Session layer (sometimes called the port layer) manages the setting up and taking down of the association between two communicating end points that is called a connection.
BASIC VISUAL PATHWAYS. A. The pathway: Vision is generated by photoreceptors in the retina, a layer of cells at the back of the eye. The information leaves the eye by way of the optic nerve, and there is a partial crossing of axons at the optic chiasm.After the chiasm, the axons are called the optic tract.The optic tract wraps around the midbrain to get to the lateral geniculate nucleus (LGN), where all the axons must synapse.. Lesions. The easiest way to demonstrate to yourself the consequences of lesions is to strike through a pathway, follow the fibers back to the retina, and see what was affected. Notice that there are lines and numbers drawn on the visual field diagram.
The two optic nerves meet at the optic chiasm. There, the optic nerve from each eye divides, and half of the nerve fibers from each side cross to the other side. Because of this arrangement, the brain receives information via both optic nerves for the left visual field and for the right visual field. Damage to an eye or the visual pathway causes different types of vision loss depending on where the damage occurs.