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 visual pathway with the course of information flow from the right (green) and left (blue) hemifields of the two eye's visual fields. The axons of the 3Â° visual afferents (the retinal ganglion cells) form the optic nerve fiber layer of the retina on their course to the optic disc. At the optic disc, the 3Â° visual afferents exit the eye and form the optic nerve. The fibers of the optic nerve that originate from ganglion cells in the nasal half of the retina (i.e., the nasal hemiretina) decussate in the optic chiasm to the opposite optic tract (Figure 15.1).