I mentioned that from the brain, and from the spinal cord, we shoot out many other nerves. So in the brain, we call them cranial nerves. Professor also mentioned the name of that, but today, let's take a little bit closer look at these nerves. So you have vestibulocochlear. One of you mentioned that in our hearing, that small movements is transducing mechanical energy to an electric signal from the neurons. And that one caused an action potential which is passed to the brain through vestibulocochlear nerve. Now, can you tell me if this one goes wrong, what will happen? What would happen to a human being if this part is damaged, or has a problem? Not able to keep balance. So we actually have a lot of disorders. Dizziness, [INAUDIBLE] Tolean has many, many, many subtypes. Some of them are because that part is damaged. Because very interestingly, our blood supply to that part, there's one single, small blood vessel. Unfortunately, unlike other parts of the body, you have many, many blood vessels coming in to support it. If one is blocked, that's okay. But from that inner part, we have one final blood vessel to supply that. If that one has a problem, then it will be damaged. We have this slide is from Professor. So she listed the names of these Nerves. If you look at the brain from the bottom, from bottom up. If you flip that from the front to the back, you have olfactory nerve, optic nerve, oculomotor nerve, troochlear nerve, trigeminal nerve, abducent nerve, facial nerve, vestibulocochlear nerve, and glossopharyngeal nerve, vagus nerve, accessory nerve, hypoglossal nerve. This is really nice. Being a Chinese spoken person, this is ten times easier than the English spoken one. So the [FOREIGN] goes, [FOREIGN]. It's really, really easy. So you will be tested on this one. This is so easy. Compare to [FOREIGN], this is ten times easier. So just to remember that. It's fun from the front to the back. I'll give the slides back to you guys, don't worry. Now, these nerves can be divided into several different characteristics. For example, we can see the r cranial nerves that are just sensory nerves. For example, one olfactory nerve, two optic nerve, and number eight vestibulocochlear nerve. Those three sets of cranial nerves are basically pure sensory nerves. The second type is motor cranial nerves. Those are the ones to motor fibers. There's number III, Oculomoter nerve. There's number IV, Trochlear nerve. There's number VI, Abducent nerve. Number 11, accessory nerve, and number 12, hypoglossal nerve. The third type is interesting. In the same nerve it combines both sensory and motor nerves. And those are, for example number five, try general nerve number seven, facial nerve number nine, glasopharyngeal nerve in number ten, vagus nerve. Now, in typical neurobiology in medical school, we are required to remember all the beginning, the middle, the end and all those information. Which we think it will be probably too detailed for this class since you're not a medical student group. But I think to show you at least once for your life, maybe you never will come back to that, it's probably warranted. So let's take a look at that. The sensory cranial nerves, one, two and eight, they have their cell bodies located in different neurons. One is from olfactory nerve, and the other one from ganglion or cochlear ganglion. And they end in different places. They are responsible for different actions. The olfactory nerve probably, it's simple, is for smell. The optic nerve is for vision. And the number VIII, Vestibulocochlear nerve. Part of that is for equilibrium, part of that is for hearing. So the equilibrium is maintained by three sets of semi-circular length tubes. It's x, y, z. And in that it's filled with lymph liquids. With that, when you move your head or you have a motion, the liquid inside will press against the cells. If you move forward, accelerate, then it will press much stronger to the back part of that tube. And that physical sense makes these cells brush against their neighbor cells, and then that's the action potential. Same thing. So you can imagine the ability to equilibrate our body posture and maintain it. It's all done by that. And if you think about those acrobats, [FOREIGN] or gymnastics, they turn so many times in the middle of the air and they land on their foot really, really precisely. So the way they can sense their spatial position is much more than ordinary people like you and me. For me, if I turn one around I basically just fall on the ground. For them they can have what how many turns like three turns in the middle and just do all these very very incredible actions. So that's the sensory. Now, olfactory nerve it connects to our nose When our smell receptors have their function it's sent to olfactory nerve and goes back. We have olfactory mucosa through a small opening and then we have olfactory bulb, optic nerve, on the other hand, it's the easiest to understand. It's from the eyeball. Our photo receptor cells, they synapse onto the secondary neurons. Then to the optic nerves. Optic nerves goes all the way back. It's very interesting. Our eyeballs are at the front of the whole head. But our cortex area which can make the integration and make sense of this information is only in the back. So our optic nerve carries information obtained from the retina and pass it on to the LGN all the way to the back side of our brain. The vestibulocochlear I've shown you. We have several of them to innovate different parts of our body. Some are bigger ones. The other ones are very finite innovations to different sets of muscle. And the damage to these ones also causes different diseases. Oculomotor nerve is one that we all use too often, everyday. We have six pairs of oculomotor nerve that moves our eyeball and changes its shape. Abducent nerve and accessory nerve [INAUDIBLE]. I mentioned that these cranial nerves, they innovate or sense from different areas in the face, in the head. But many times we have small damages to them and that will cause clinical diseases. For example, this patient suffers from an injury to a abducent nerve or the aoculamotor paralysis, so the eyeballs are not sort of parallel to each other. Hypoglossal nerve tongue. In the mixed cranial nerve category, we have the trigeminal. It innervates and also senses. We have our facial nerve. That's the one many times you can see people have facial nerve injuries. It goes from here. These are all wonderful drawings of facial nerve once it's damaged, you can see the [FOREIGN] what we call. Next one is Glossopharyngeal nerve. That's where they come from. Vagus nerve from here. So those are the 12 cranial nerves that innovates basically from here up. And they are very important for all of the movements in our upper area.
