Final answer:
The optic nerve, also known as Cranial Nerve II, begins at the retina of each eye, passes through the optic canals, and meets at the optic chiasm. It transmits visual information to the brain and is essential for sight. The optic nerve's function and pathway are vital for our visual fields, with each half of the visual field being processed by the opposite side of the brain.
Step-by-step explanation:
The optic nerve (Cranial Nerve II) is responsible for transmitting visual information from the retina to the brain. It enters the cranium through the optic canals and meets at a point called the optic chiasm, which is located below the cerebral cortex at the front of the brain. The optic nerve is responsible for our sense of sight and functions by carrying impulses from the photoreceptor cells in the retina, which detect light and color. These impulses are routed via different pathways depending on which half of the visual field they represent. After the optic nerve fibers pass through the optic chiasm, they become known as the optic tracts. The optic tracts contain the axons that lead to various brain regions where the visual information is processed.
Visual Pathway and Fields
The processing of visual fields is segregated; information from the right field of vision is sent to the left side of the brain, and vice versa. This is because the optic nerve fibers partially cross over at the chiasm. As a result, damage along the optic nerve or at the chiasm can result in specific visual field deficits. For example, a pituitary tumor pressing on the optic chiasm could cause loss of peripheral vision.