Cranial Nerves

3654 Words Apr 2nd, 2012 15 Pages
Cranial Nerves

The human body is a unique and fascinating entity. There is not much notice taken of the features the human body is capable of. The brain is necessary to perform day-to-day actions, such as the ability to speak, and see amongst us. This brain is made up of simple mater (Pia mater, Arachnoid mater, Dura mater) and the cranial surface to protect the brain. We live our daily lives without acknowledging the importance of this organ, the brain, unless you’re a medical student of course! Despite that people go on with their daily activities using the human natural senses. Looking at the world through the eyes, watching for any danger around us; ears for hearing the sounds detecting something that may call for danger, the
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The second cranial nerve is optic nerve. Optic nerves main function is vision, one of the important senses of the human body. Allowing oneself to see around them. The cell bodies of the optic nerve are located in the Retina (ganglion cells). Optic nerve begins with unmyelinated axons of the rentinal ganglion cells, which later become myelinated in the optic disc. CN II enters the cranium via the optic canal. The retina has bipolar cells that are connected to the special sensory fibers (rods and cone cells). When light hits the rod and cone cells, electrical impulse are relayed and transmitted to the bipolar cells. That is when the bipolar cells transmit electrical activity to the CNS through the optic nerve. Loosing the sense of vision can be very detrimental. Some of the dysfunctions that occur with CN II are immediate monocular blindness (partial or complete), visual field deficits, blurring, scotomata, and monocular diplopia. There can be many possible causes for these dysfunctions to name a few, immediate loss of vision is due to injury to optic nerve due to ischemia or death, delayed vision loss is due to infarction of the optic nerve or less frequently by hematoma surrounding the nerve. Complete monocular blindness is usually due to non-organic disorders. Blurring and scotomata are due to trauma to the cornea, vitreous tears, traumatically induced