WEBVTT 00:00:02.480 --> 00:00:03.472 [SOUND EFFECT] 00:00:06.337 --> 00:00:08.350 SPEAKER: All right, ninja nerds. 00:00:08.350 --> 00:00:11.050 So we've already covered the brain in another video. 00:00:11.050 --> 00:00:12.593 Our intention in this video is just 00:00:12.593 --> 00:00:14.260 to be able to give you guys another view 00:00:14.260 --> 00:00:16.544 of the brain and some of the internal structures. 00:00:16.544 --> 00:00:18.760 So let's go ahead and dive right into this. 00:00:18.760 --> 00:00:20.860 So first off, if you remember from before, 00:00:20.860 --> 00:00:24.550 we had this central sulcus here on the side. 00:00:24.550 --> 00:00:27.910 And it's just this little groove right here, 00:00:27.910 --> 00:00:30.160 running right there. 00:00:30.160 --> 00:00:32.697 This guy right there is actually called the central sulcus. 00:00:32.697 --> 00:00:34.780 So again, the central sulcus is this little groove 00:00:34.780 --> 00:00:37.240 right here running all the way up right there. 00:00:37.240 --> 00:00:38.830 And what's the purpose of it? 00:00:38.830 --> 00:00:40.900 The central sulcus separates the frontal lobe 00:00:40.900 --> 00:00:41.973 from the parietal lobe. 00:00:41.973 --> 00:00:43.390 So if I come up the central sulcus 00:00:43.390 --> 00:00:46.720 one more time, if I go right in front of this sulcus 00:00:46.720 --> 00:00:48.640 to this gyrus right there-- because remember, 00:00:48.640 --> 00:00:50.462 sulcus is this little divot. 00:00:50.462 --> 00:00:53.090 And then a gyrus is this big, fat, lumpy thing right there, 00:00:53.090 --> 00:00:53.800 right? 00:00:53.800 --> 00:00:56.200 This gyrus in front of the central sulcus 00:00:56.200 --> 00:00:58.420 is called the precentral gyrus. 00:00:58.420 --> 00:01:01.686 It's also where the primary motor cortex is. 00:01:01.686 --> 00:01:04.019 And if I follow the central sulcus because back up again 00:01:04.019 --> 00:01:06.940 and I go to this fat gyrus that's right behind it, 00:01:06.940 --> 00:01:09.880 that guy right there is called the postcentral gyrus. 00:01:09.880 --> 00:01:13.120 And that's where the primary somatosensory cortex is. 00:01:13.120 --> 00:01:13.660 All right? 00:01:13.660 --> 00:01:15.067 And then if I were to go in front 00:01:15.067 --> 00:01:17.650 of the primary motor here, which is where the precentral gyrus 00:01:17.650 --> 00:01:19.392 is, I'd hit the premotor. 00:01:19.392 --> 00:01:20.850 And then you come in front of that, 00:01:20.850 --> 00:01:23.170 and you hit what's called the prefrontal cortex and so 00:01:23.170 --> 00:01:23.837 on and so forth. 00:01:23.837 --> 00:01:26.080 There's even called the eyelids, stuff like that. 00:01:26.080 --> 00:01:29.410 But again, basic important thing right here 00:01:29.410 --> 00:01:33.910 is central sulcus, precentral gyrus, postcentral gyrus. 00:01:33.910 --> 00:01:35.410 The precentral gyrus is functionally 00:01:35.410 --> 00:01:37.630 called the primary motor cortex. 00:01:37.630 --> 00:01:39.550 The postcentral gyrus is functionally 00:01:39.550 --> 00:01:42.670 called the primary somatosensory cortex. 00:01:42.670 --> 00:01:43.363 OK? 00:01:43.363 --> 00:01:45.280 Then if I were to continue to work my way back 00:01:45.280 --> 00:01:48.427 to see where else does the parietal lobe-- 00:01:48.427 --> 00:01:50.260 where does that terminate, and where does it 00:01:50.260 --> 00:01:51.515 go to another lobe? 00:01:51.515 --> 00:01:52.890 So if I come over here, I'm going 00:01:52.890 --> 00:01:56.680 to take this brain and kind of, like, open it up here. 00:01:56.680 --> 00:01:58.820 Turn it around. 00:01:58.820 --> 00:02:01.800 So if we look here, you'll see another sulcus right there. 00:02:01.800 --> 00:02:03.670 That sulcus right there is actually 00:02:03.670 --> 00:02:06.670 called the parietal occipital sulcus. 00:02:06.670 --> 00:02:08.130 And the parietal occipital sulcus 00:02:08.130 --> 00:02:11.632 is what separates the parietal lobe from the occipital lobe. 00:02:11.632 --> 00:02:13.090 So back here is the occipital lobe. 00:02:13.090 --> 00:02:14.500 I'll give you guys another view here in a second. 00:02:14.500 --> 00:02:16.570 Just let me repeat that one more time again. 00:02:16.570 --> 00:02:18.940 This is the parietal occipital sulcus. 00:02:18.940 --> 00:02:20.340 And the parietal occipital sulcus 00:02:20.340 --> 00:02:22.570 is what separates the parietal lobe, which 00:02:22.570 --> 00:02:24.940 begins right after the central sulcus, 00:02:24.940 --> 00:02:26.380 all the way up to this sulcus. 00:02:26.380 --> 00:02:28.130 And it separates the parietal lobe, again, 00:02:28.130 --> 00:02:29.622 from the occipital lobe. 00:02:29.622 --> 00:02:31.330 All right, guys, so if we look back here, 00:02:31.330 --> 00:02:33.130 we have the occipital lobe back there. 00:02:33.130 --> 00:02:34.963 Again, and what separates the occipital lobe 00:02:34.963 --> 00:02:38.440 from the parietal lobe is the parietal occipital sulcus. 00:02:38.440 --> 00:02:40.030 Again, this is the occipital lobe. 00:02:40.030 --> 00:02:43.280 In the occipital lobe, there is a specific cortex 00:02:43.280 --> 00:02:46.240 that's actually called the primary visual cortex. 00:02:46.240 --> 00:02:49.750 And so that's where, you know, the actual signal 00:02:49.750 --> 00:02:54.070 transduction that comes from our retina that portrays basically 00:02:54.070 --> 00:02:57.670 light, we can actually have the perception 00:02:57.670 --> 00:03:00.450 of that light in this area to be able to perceive what we see-- 00:03:00.450 --> 00:03:03.020 you know, certain types of objects and shapes and colors 00:03:03.020 --> 00:03:04.160 and so on and so forth. 00:03:04.160 --> 00:03:06.280 So again, primary visual cortex is located 00:03:06.280 --> 00:03:08.530 within the occipital lobe. 00:03:08.530 --> 00:03:10.540 And then if I turn this to the right side, 00:03:10.540 --> 00:03:13.690 our lateral side over here, we can see another sulcus. 00:03:13.690 --> 00:03:15.763 And this sulcus is right here. 00:03:15.763 --> 00:03:17.430 Actually, let me move rubber band, guys, 00:03:17.430 --> 00:03:18.980 so we can see a little better. 00:03:18.980 --> 00:03:21.460 If I move that rubber band right there and I move my finger 00:03:21.460 --> 00:03:23.740 right-- or this little pointer here-- 00:03:23.740 --> 00:03:26.470 right through this area, right through that sulcus, 00:03:26.470 --> 00:03:29.910 that sulcus right there is called the lateral sulcus. 00:03:29.910 --> 00:03:32.650 Now, the lateral sulcus is the sulcus 00:03:32.650 --> 00:03:34.327 that separates the temporal lobe, again, 00:03:34.327 --> 00:03:36.160 from the parietal lobe and even a little bit 00:03:36.160 --> 00:03:37.510 from the frontal lobe. 00:03:37.510 --> 00:03:39.903 But this lateral sulcus runs right down here, 00:03:39.903 --> 00:03:41.320 and it separates the temporal lobe 00:03:41.320 --> 00:03:43.153 from the parietal lobe and even a little bit 00:03:43.153 --> 00:03:44.120 from the frontal lobe. 00:03:44.120 --> 00:03:45.953 So again, what is this lobe right here then? 00:03:45.953 --> 00:03:48.310 I already said, this is the temporal lobe. 00:03:48.310 --> 00:03:50.630 And the temporal lobe has a specific cortex in it, 00:03:50.630 --> 00:03:53.040 which is called the primary auditory cortex. 00:03:53.040 --> 00:03:55.510 And the primary auditory cortex is 00:03:55.510 --> 00:03:57.460 going to be where we take specifically sound 00:03:57.460 --> 00:04:00.100 and hearing from the cochlea in our inner ear 00:04:00.100 --> 00:04:03.070 and we bring it to this area to be able to perceive and put 00:04:03.070 --> 00:04:05.020 together different types of memories 00:04:05.020 --> 00:04:07.210 to understand what we're hearing, 00:04:07.210 --> 00:04:09.690 and we're able to perceive that hearing, right? 00:04:09.690 --> 00:04:13.137 All right, so that's where the primary auditory cortex is. 00:04:13.137 --> 00:04:14.470 Again, that's the temporal lobe. 00:04:14.470 --> 00:04:16.459 There is another lobe we can't see. 00:04:16.459 --> 00:04:17.870 And it's going to be deep to the temporal lobe, 00:04:17.870 --> 00:04:19.990 and that's called the insula All right, so let's go ahead 00:04:19.990 --> 00:04:21.573 and show you two more other areas that 00:04:21.573 --> 00:04:23.000 are kind of important here. 00:04:23.000 --> 00:04:24.542 And what I'm going to do is it's only 00:04:24.542 --> 00:04:26.530 on the left side of the frontal lobe. 00:04:26.530 --> 00:04:27.915 It's called the Broca's area. 00:04:27.915 --> 00:04:29.290 So the Broca's area is just going 00:04:29.290 --> 00:04:31.390 to be this little area over here on the left side 00:04:31.390 --> 00:04:32.720 of the frontal lobe. 00:04:32.720 --> 00:04:35.000 Again, it controls the muscles of speech production, 00:04:35.000 --> 00:04:38.440 so being able to change the shape of our mouth 00:04:38.440 --> 00:04:41.230 and other types of muscles that are basically assisting 00:04:41.230 --> 00:04:44.920 with pronunciation and production of consonants 00:04:44.920 --> 00:04:45.890 and so on and so forth. 00:04:45.890 --> 00:04:48.580 But again, just controls the muscles of speech production. 00:04:48.580 --> 00:04:50.430 There's another area back here. 00:04:50.430 --> 00:04:53.015 It's kind of an overlapping area right around here. 00:04:53.015 --> 00:04:54.640 That's called the word Wernicke's area. 00:04:54.640 --> 00:04:57.223 Basically he just helps us to be able to understand what we're 00:04:57.223 --> 00:04:58.810 hearing and put those words together 00:04:58.810 --> 00:05:01.480 in a appropriate manner that when we speak it, 00:05:01.480 --> 00:05:02.240 it makes sense. 00:05:02.240 --> 00:05:02.740 OK? 00:05:02.740 --> 00:05:05.110 So he does help with being able to play a role also 00:05:05.110 --> 00:05:08.020 in speech production but also understanding speech. 00:05:08.020 --> 00:05:10.060 All right, so that's the Wernicke's area. 00:05:10.060 --> 00:05:11.810 Now what I'm going to do is we're actually 00:05:11.810 --> 00:05:14.828 going to kind of take this guy here and turn it 00:05:14.828 --> 00:05:16.870 forward here so I can show you another structure. 00:05:16.870 --> 00:05:18.730 This whole thing up here is the cerebrum. 00:05:18.730 --> 00:05:20.830 And the cerebrum-- and it's actually 00:05:20.830 --> 00:05:23.390 derived from what's called the telencephalon, OK? 00:05:23.390 --> 00:05:24.880 That's its scientific name. 00:05:24.880 --> 00:05:25.900 But what I'm going to do is I'm going 00:05:25.900 --> 00:05:28.233 to kind of separate these two cerebral hemispheres right 00:05:28.233 --> 00:05:29.060 there. 00:05:29.060 --> 00:05:31.000 And what happens is there's a fissure that 00:05:31.000 --> 00:05:32.710 runs right between these two-- 00:05:32.710 --> 00:05:34.140 right between these two. 00:05:34.140 --> 00:05:36.730 And that's called the longitudinal fissure. 00:05:36.730 --> 00:05:38.590 Called the longitudinal fissure. 00:05:38.590 --> 00:05:41.530 Why I mentioned that is there's what's 00:05:41.530 --> 00:05:43.300 called dural sinuses that are veins 00:05:43.300 --> 00:05:46.030 that run through this area, and we have to protect them. 00:05:46.030 --> 00:05:48.630 So there's these things called dural septum, which are just 00:05:48.630 --> 00:05:51.070 little septal partitions of dural matter 00:05:51.070 --> 00:05:53.440 that dip down into this longitudinal fissure 00:05:53.440 --> 00:05:55.270 and protect the dural sinuses. 00:05:55.270 --> 00:05:58.390 And that dural septa that comes in here in the longitudinal 00:05:58.390 --> 00:06:02.410 fissure is called the falx, F-A-L-X, cerebri. 00:06:02.410 --> 00:06:04.670 So falx cerebri. 00:06:04.670 --> 00:06:07.210 And again, it's right here in the longitudinal fissure. 00:06:07.210 --> 00:06:10.960 All right, now I'm going to go ahead and turn this guy around 00:06:10.960 --> 00:06:13.300 so we can tell you guys about another one. 00:06:13.300 --> 00:06:14.800 So I'm going to come back here, back 00:06:14.800 --> 00:06:17.207 where the occipital lobe was. 00:06:17.207 --> 00:06:19.540 And if you remember, this was the occipital lobe, right? 00:06:19.540 --> 00:06:22.243 Well, how do we know-- we know where the parietal lobe is. 00:06:22.243 --> 00:06:24.160 You remember, it starts at the central sulcus, 00:06:24.160 --> 00:06:26.268 and then it ends at the parietal occipital sulcus. 00:06:26.268 --> 00:06:28.060 And that's where the occipital lobe begins, 00:06:28.060 --> 00:06:29.435 at the parietal occipital sulcus. 00:06:29.435 --> 00:06:30.520 Where does it end? 00:06:30.520 --> 00:06:32.380 It ends right back here where there's 00:06:32.380 --> 00:06:35.950 this little space in here right between the occipital lobe 00:06:35.950 --> 00:06:37.900 and the cerebellum right there. 00:06:37.900 --> 00:06:41.315 So in between here is what's called the transverse fissure. 00:06:41.315 --> 00:06:42.940 And the transverse fissure is important 00:06:42.940 --> 00:06:45.310 because there's another dural septa that 00:06:45.310 --> 00:06:47.650 actually dips in that area. 00:06:47.650 --> 00:06:51.550 And that right there is called the tentorium cerebelli. 00:06:51.550 --> 00:06:52.720 Cerebelli, OK? 00:06:52.720 --> 00:06:54.100 Tentorium cerebelli. 00:06:54.100 --> 00:06:57.670 And it's just a dural matter partition or septa 00:06:57.670 --> 00:06:59.460 that dips in that area. 00:06:59.460 --> 00:07:00.322 OK? 00:07:00.322 --> 00:07:01.780 Now what we're going to do is we're 00:07:01.780 --> 00:07:04.280 going to go ahead deeper into the structures of the cerebrum 00:07:04.280 --> 00:07:05.920 and take a look at that, OK? 00:07:05.920 --> 00:07:06.780 All right, guys, so now what I'm going to do 00:07:06.780 --> 00:07:07.960 is I'm going to show some other structures 00:07:07.960 --> 00:07:09.500 underneath the cerebrum. 00:07:09.500 --> 00:07:11.462 So deep in the cerebrum-- 00:07:11.462 --> 00:07:12.670 I just want to show you guys. 00:07:12.670 --> 00:07:15.970 If you see all this white right here, this is all white matter. 00:07:15.970 --> 00:07:20.020 And what white matter is, is it's just myelinated axons. 00:07:20.020 --> 00:07:22.000 So it's myelinated axons. 00:07:22.000 --> 00:07:23.812 And myelinated axons just means it 00:07:23.812 --> 00:07:25.270 has this thing called myelin, which 00:07:25.270 --> 00:07:27.070 is made up of fat and proteins. 00:07:27.070 --> 00:07:29.000 It helps with basically nerve conduction, 00:07:29.000 --> 00:07:30.250 the speed of nerve conduction. 00:07:30.250 --> 00:07:32.260 But anyway, myelinated axons right here 00:07:32.260 --> 00:07:33.640 is going to be the white matter. 00:07:33.640 --> 00:07:37.510 All this pink stuff around the edges or the outsides of it, 00:07:37.510 --> 00:07:40.600 this is all part of what's called our cerebral cortex. 00:07:40.600 --> 00:07:42.280 And that's made of gray matter. 00:07:42.280 --> 00:07:45.560 And gray matter is actually unmyelinated cell body. 00:07:45.560 --> 00:07:47.580 So there's no myelin around the cell bodies. 00:07:47.580 --> 00:07:48.080 OK? 00:07:48.080 --> 00:07:50.710 So unmyelinated cell bodies is our gray matter, which 00:07:50.710 --> 00:07:52.930 makes up the cerebral cortex. 00:07:52.930 --> 00:07:55.212 You can think of that like as the thinking tissue. 00:07:55.212 --> 00:07:57.670 So that's the part where they're the biomechanical centers, 00:07:57.670 --> 00:07:59.020 and they basically-- 00:07:59.020 --> 00:08:01.150 they're the ones that control a lot of the thinking 00:08:01.150 --> 00:08:02.230 or conscious thought. 00:08:02.230 --> 00:08:04.070 This white matter, you could think of that 00:08:04.070 --> 00:08:05.590 as like transmission tissue. 00:08:05.590 --> 00:08:08.230 It's basically responsible for being able to transmit impulses 00:08:08.230 --> 00:08:10.050 to and from certain areas. 00:08:10.050 --> 00:08:10.660 OK? 00:08:10.660 --> 00:08:13.060 So again, that shows you the cerebral cortex 00:08:13.060 --> 00:08:15.410 and, again, shows you the white matter right there. 00:08:15.410 --> 00:08:16.130 Now what we're going to do is we're 00:08:16.130 --> 00:08:18.297 going to take a look at some other structures, which 00:08:18.297 --> 00:08:20.425 is in the diencephalon and the ventricles. 00:08:20.425 --> 00:08:23.050 All right, guys, I have the left cerebral hemisphere right now. 00:08:23.050 --> 00:08:23.680 What I'm going to do is I'm going 00:08:23.680 --> 00:08:25.972 to take this top piece off so we can take a deeper look 00:08:25.972 --> 00:08:27.593 at some structures inside here. 00:08:27.593 --> 00:08:29.260 All right, so if we take a look in here, 00:08:29.260 --> 00:08:31.540 right now we're kind of in the lateral ventricle. 00:08:31.540 --> 00:08:33.850 And ventricles are just basically cavities 00:08:33.850 --> 00:08:37.820 within the actual brain and also within the brain stem. 00:08:37.820 --> 00:08:40.539 And it contains what's called cerebral spinal fluid. 00:08:40.539 --> 00:08:43.570 And we'll talk about that more in the neurophysiology stuff. 00:08:43.570 --> 00:08:45.460 But if you look right here, sitting 00:08:45.460 --> 00:08:48.267 in the bottom of the lateral ventricle down here, 00:08:48.267 --> 00:08:50.600 this is actually-- if you remember from the other video, 00:08:50.600 --> 00:08:52.360 it's called the hippocampus. 00:08:52.360 --> 00:08:54.520 And the hippocampus is a limbic nuclei. 00:08:54.520 --> 00:08:57.100 So it plays a role with memory and emotions 00:08:57.100 --> 00:08:58.518 and so on and so forth. 00:08:58.518 --> 00:09:00.310 So it does play a very, very important role 00:09:00.310 --> 00:09:02.560 within, basically, memory. 00:09:02.560 --> 00:09:04.300 If you look here, that's 190. 00:09:04.300 --> 00:09:06.640 And if I come up here and I follow these white fibers 00:09:06.640 --> 00:09:07.318 like 186-- 00:09:07.318 --> 00:09:08.860 if I follow it all the way from here, 00:09:08.860 --> 00:09:13.790 all the way back, and then I come back up this way-- 00:09:13.790 --> 00:09:16.530 so again, all the way up here, following this guy, 00:09:16.530 --> 00:09:17.950 and all the way back this way. 00:09:17.950 --> 00:09:19.580 These fibers are very important. 00:09:19.580 --> 00:09:21.865 They're called association fibers. 00:09:21.865 --> 00:09:24.760 And association fibers are what allow 00:09:24.760 --> 00:09:27.520 for the movement of impulses to go from front, 00:09:27.520 --> 00:09:30.460 from in front of the cerebrum to the back of the cerebrum 00:09:30.460 --> 00:09:31.830 or vice versa. 00:09:31.830 --> 00:09:32.330 OK? 00:09:32.330 --> 00:09:34.630 So again, these are association fibers, 00:09:34.630 --> 00:09:36.010 and this is the hippocampus. 00:09:36.010 --> 00:09:38.110 And then this whole cavity right here-- 00:09:38.110 --> 00:09:40.330 so like, for example, this is the inferior horn. 00:09:40.330 --> 00:09:41.470 This is the posterior horn. 00:09:41.470 --> 00:09:43.512 And then we'll see the anterior horn in a second. 00:09:43.512 --> 00:09:45.500 That's all the lateral ventricle. 00:09:45.500 --> 00:09:46.000 OK? 00:09:46.000 --> 00:09:47.667 And again, you can see the white matter. 00:09:47.667 --> 00:09:49.790 And then you can see the gray matter out there. 00:09:49.790 --> 00:09:53.020 So the last structure here is going to be number 206, 00:09:53.020 --> 00:09:56.810 and this is actually called the internal capsule. 00:09:56.810 --> 00:09:58.990 And the internal capsule is actually specific fiber. 00:09:58.990 --> 00:10:01.240 It's called a projection fiber. 00:10:01.240 --> 00:10:03.880 And projection fibers are important for being 00:10:03.880 --> 00:10:06.280 able to bring sensory information up 00:10:06.280 --> 00:10:07.870 to the cerebral cortex, OK? 00:10:07.870 --> 00:10:10.488 So they bring information up, all right? 00:10:10.488 --> 00:10:13.030 But they do-- they can allow for information to go down also. 00:10:13.030 --> 00:10:16.030 So they just basically offer movement to go up and down. 00:10:16.030 --> 00:10:19.100 So association is back and forth, so back and front, 00:10:19.100 --> 00:10:19.990 back and front. 00:10:19.990 --> 00:10:21.910 And projection is up and down, up and down. 00:10:21.910 --> 00:10:23.910 And we'll look at another one in a second called 00:10:23.910 --> 00:10:25.220 the commissural fibers. 00:10:25.220 --> 00:10:25.720 All right? 00:10:25.720 --> 00:10:26.920 Now we're going to go ahead and turn it around and look 00:10:26.920 --> 00:10:28.270 at some other structures, guys. 00:10:28.270 --> 00:10:29.640 All right, so I just turned it around, guys. 00:10:29.640 --> 00:10:31.780 So again, we're looking here at kind of like the other view. 00:10:31.780 --> 00:10:32.738 I was on the back side. 00:10:32.738 --> 00:10:35.680 Now we're looking over here on the front side. 00:10:35.680 --> 00:10:38.120 So if you look right here, there's a nuclei right here. 00:10:38.120 --> 00:10:39.325 It's a basal nuclei. 00:10:39.325 --> 00:10:41.200 And basal nuclei just are important for being 00:10:41.200 --> 00:10:44.122 able to dampen or smooth out certain motor movements. 00:10:44.122 --> 00:10:44.830 He's one of them. 00:10:44.830 --> 00:10:46.450 He's called the caudate nucleus. 00:10:46.450 --> 00:10:48.430 So that's the caudate nucleus right there. 00:10:48.430 --> 00:10:51.160 But this whole-- remember I told you there was another anterior 00:10:51.160 --> 00:10:52.780 horn of that lateral ventricle. 00:10:52.780 --> 00:10:54.460 So there's a little cavity here. 00:10:54.460 --> 00:10:57.190 And this whole cavity right here is the lateral ventricle. 00:10:57.190 --> 00:10:59.568 And if you look right here, this structure right there 00:10:59.568 --> 00:11:02.110 is actually called the-- it's a choroid plexus, because there 00:11:02.110 --> 00:11:04.390 is a choroid plexus, which is basically 00:11:04.390 --> 00:11:07.150 made up of ependymal cells and pia mater. 00:11:07.150 --> 00:11:09.607 And you're also going to have your capillaries in there, 00:11:09.607 --> 00:11:12.190 and it's what helps to be able to make the cerebrospinal fluid 00:11:12.190 --> 00:11:13.540 and circulate it. 00:11:13.540 --> 00:11:15.712 So again, this is going to be the lateral ventricle, 00:11:15.712 --> 00:11:16.420 this cavity here. 00:11:16.420 --> 00:11:18.440 Imagine it, like, bathing this nucleus here. 00:11:18.440 --> 00:11:20.620 Imagine it bathing this caudate nucleus. 00:11:20.620 --> 00:11:22.120 And imagine this whole cavity filled 00:11:22.120 --> 00:11:23.830 with cerebrospinal fluid, and that's 00:11:23.830 --> 00:11:27.740 made by this thing called the choroid plexus. 00:11:27.740 --> 00:11:30.320 And then you can see this fiber right there. 00:11:30.320 --> 00:11:31.960 There's another white matter fiber, 00:11:31.960 --> 00:11:34.360 and this is actually called the fornix. 00:11:34.360 --> 00:11:37.870 And the fornix is a white fiber that actually-- it's 00:11:37.870 --> 00:11:40.180 a tract, which is a bundle of axons 00:11:40.180 --> 00:11:41.830 in the central nervous system that 00:11:41.830 --> 00:11:44.810 connects multiple limbic nuclei together. 00:11:44.810 --> 00:11:46.690 So again, this structure right here, 00:11:46.690 --> 00:11:48.757 all the way from here, all the way from here, 00:11:48.757 --> 00:11:49.840 this is called the fornix. 00:11:49.840 --> 00:11:51.423 And the fornix is basically what helps 00:11:51.423 --> 00:11:54.200 to be able to connect multiple limbic nuclei together. 00:11:54.200 --> 00:11:56.110 So again, last time, lateral ventricle, 00:11:56.110 --> 00:11:59.170 caudate nucleus, choroid plexus of the lateral ventricle, 00:11:59.170 --> 00:11:59.880 and the fornix. 00:11:59.880 --> 00:12:01.600 All right, so now we're going to go ahead and look 00:12:01.600 --> 00:12:03.870 at some of these other structures in the diencephalon. 00:12:03.870 --> 00:12:05.245 All right, guys, so this is right 00:12:05.245 --> 00:12:06.700 here is the corpus callosum. 00:12:06.700 --> 00:12:09.463 And the corpus callosum number 145 here, 00:12:09.463 --> 00:12:11.380 this is actually going to be made up of what's 00:12:11.380 --> 00:12:12.760 called commissural fibers. 00:12:12.760 --> 00:12:14.860 And commissural fibers are just, again, 00:12:14.860 --> 00:12:18.760 myelinated axons that allow for transmission of impulses 00:12:18.760 --> 00:12:20.415 from left cerebral hemisphere to right 00:12:20.415 --> 00:12:21.790 or from right cerebral hemisphere 00:12:21.790 --> 00:12:23.530 to left cerebral hemisphere. 00:12:23.530 --> 00:12:26.570 So it's very important for that connection. 00:12:26.570 --> 00:12:28.000 It's also an area that's commonly 00:12:28.000 --> 00:12:30.220 damaged during concussions. 00:12:30.220 --> 00:12:32.290 And it's actually been found that women 00:12:32.290 --> 00:12:35.200 have more commissural fibers than men do, 00:12:35.200 --> 00:12:38.140 which allows for them to be able to have a little bit better-- 00:12:38.140 --> 00:12:40.960 be better at multitasking and stuff like that. 00:12:40.960 --> 00:12:43.738 And it also plays a role in epilepsy and stuff like that, 00:12:43.738 --> 00:12:45.280 but we're not going to get into that. 00:12:45.280 --> 00:12:47.380 So again, corpus callosum there. 00:12:47.380 --> 00:12:51.160 If you look here, there's a membrane 146. 00:12:51.160 --> 00:12:54.430 So this thin membrane here is called the septum pellucidum. 00:12:54.430 --> 00:12:56.650 And underneath the septum pellucidum 00:12:56.650 --> 00:12:59.710 is that lateral ventricle that I was showing you guys before. 00:12:59.710 --> 00:13:01.930 So underneath this septum pellucidum 00:13:01.930 --> 00:13:03.010 is the lateral ventricle. 00:13:03.010 --> 00:13:04.046 OK? 00:13:04.046 --> 00:13:06.388 So it's just a thin membrane that separates the two 00:13:06.388 --> 00:13:07.180 lateral ventricles. 00:13:07.180 --> 00:13:09.070 Because, again, we have a lateral ventricle 00:13:09.070 --> 00:13:10.690 in one cerebral hemisphere. 00:13:10.690 --> 00:13:11.825 Let's say the right one. 00:13:11.825 --> 00:13:13.450 And we'll also have a lateral ventricle 00:13:13.450 --> 00:13:14.783 in the left cerebral hemisphere. 00:13:14.783 --> 00:13:16.900 And the structure separating them, this membrane, 00:13:16.900 --> 00:13:18.970 is the septum pellucidum. 00:13:18.970 --> 00:13:21.520 If you guys look at the ventricle model we have, 00:13:21.520 --> 00:13:23.770 you'll also see a better way of looking at that also. 00:13:23.770 --> 00:13:25.780 All right, let's come back here again. 00:13:25.780 --> 00:13:28.450 148 here, this is the fornix. 00:13:28.450 --> 00:13:29.950 And again, that was that fiber tract 00:13:29.950 --> 00:13:33.190 that connects a lot of the limbic nuclei together. 00:13:33.190 --> 00:13:34.990 If I imagine I draw a whole circle-- 00:13:34.990 --> 00:13:37.690 say I do a whole circle all the way around here 00:13:37.690 --> 00:13:38.970 or you imagine like an egg. 00:13:38.970 --> 00:13:40.720 An egg is kind of like oval-shaped, right? 00:13:40.720 --> 00:13:43.578 So this whole thing right here is the thalamus. 00:13:43.578 --> 00:13:46.120 So this whole egg structure here with a whole bunch of nuclei 00:13:46.120 --> 00:13:48.160 is the thalamus. 00:13:48.160 --> 00:13:51.570 And the thalamus is actually the relay station 00:13:51.570 --> 00:13:54.070 for a lot of sensory information going up into the cerebrum, 00:13:54.070 --> 00:13:56.850 because he has tons of nuclei that regulate that activity. 00:13:56.850 --> 00:13:59.225 Then if you look there, that little brown structure right 00:13:59.225 --> 00:14:03.130 there, that's called the intermediate mass. 00:14:03.130 --> 00:14:06.010 And it basically is like an interthalamic adhesion 00:14:06.010 --> 00:14:08.230 between the two thalami, because you 00:14:08.230 --> 00:14:09.430 have a thalamus in your right cerebral hemisphere, 00:14:09.430 --> 00:14:11.805 and you have a thalamus in your left cerebral hemisphere. 00:14:11.805 --> 00:14:13.300 So you have two of them. 00:14:13.300 --> 00:14:15.180 If you actually imagine here-- 00:14:15.180 --> 00:14:17.840 imagine this being an eye, like a bird's eye. 00:14:17.840 --> 00:14:18.340 OK? 00:14:18.340 --> 00:14:20.110 So if you can imagine it, you can imagine the bird's eye, 00:14:20.110 --> 00:14:21.160 which is kind of like the white of the eye 00:14:21.160 --> 00:14:22.215 is like the thalamus. 00:14:22.215 --> 00:14:23.590 And then the pupil right there is 00:14:23.590 --> 00:14:25.270 where the intermediate mass is. 00:14:25.270 --> 00:14:28.263 And if you imagine the bird's beak right there, 00:14:28.263 --> 00:14:29.680 this right there, that bird's beak 00:14:29.680 --> 00:14:30.888 is actually the hypothalamus. 00:14:30.888 --> 00:14:33.590 So they can kind of say look at the bird's eye and a bird's 00:14:33.590 --> 00:14:34.090 beak. 00:14:34.090 --> 00:14:35.170 And again, the bird's eye is made up 00:14:35.170 --> 00:14:36.753 of the thalamus and intermediate mass. 00:14:36.753 --> 00:14:39.190 And the bird's beak is the hypothalamus. 00:14:39.190 --> 00:14:41.440 If you look back here, you have what's 00:14:41.440 --> 00:14:45.643 called the pineal gland, which is a part of the epithalamus. 00:14:45.643 --> 00:14:47.560 Then you're also going to notice this little-- 00:14:47.560 --> 00:14:49.210 the hypothalamus has this little stalk 00:14:49.210 --> 00:14:52.195 here on this side that connects to the pituitary gland that 00:14:52.195 --> 00:14:54.070 would sit right underneath the optic chiasma. 00:14:54.070 --> 00:14:57.493 Actually, this is-- if you look at 170 there, that's-- 00:14:57.493 --> 00:14:59.410 where the optic nerves cross, there's actually 00:14:59.410 --> 00:15:00.850 called the optic chiasma. 00:15:00.850 --> 00:15:02.660 So for example, this is the right cerebrum, 00:15:02.660 --> 00:15:04.460 so this would be the right optic nerve here. 00:15:04.460 --> 00:15:06.252 And it's getting ready-- some of its fibers 00:15:06.252 --> 00:15:08.250 will cross over to the left side. 00:15:08.250 --> 00:15:08.750 OK? 00:15:08.750 --> 00:15:10.708 So that's kind of like the optic chiasma there. 00:15:10.708 --> 00:15:13.072 And then this part right there is the infundibulum. 00:15:13.072 --> 00:15:14.780 But if you look right there, that little, 00:15:14.780 --> 00:15:17.420 like, ball there, that right there is 00:15:17.420 --> 00:15:19.753 called the mammillary bodies. 00:15:19.753 --> 00:15:21.170 And the mammillary bodies are also 00:15:21.170 --> 00:15:23.930 important because they play a role within certain types 00:15:23.930 --> 00:15:26.300 of olfactory pathways. 00:15:26.300 --> 00:15:28.060 So they play a role in smell. 00:15:28.060 --> 00:15:30.393 That's the mammillary bodies, and they're limbic nuclei. 00:15:30.393 --> 00:15:32.570 So they play a role in recollective memory, 00:15:32.570 --> 00:15:34.030 stuff like that. 00:15:34.030 --> 00:15:36.562 OK, if you come over here, we're going 00:15:36.562 --> 00:15:37.770 to see some other structures. 00:15:37.770 --> 00:15:40.538 Now we're getting ready to start moving into the brainstem. 00:15:40.538 --> 00:15:42.080 So as we get ready to move over here, 00:15:42.080 --> 00:15:43.455 let's actually hit our brainstem. 00:15:43.455 --> 00:15:46.460 So if you look right here, all this part right here, 00:15:46.460 --> 00:15:48.440 this is all called the midbrain. 00:15:48.440 --> 00:15:51.080 And they also call it the mesencephalon. 00:15:51.080 --> 00:15:53.300 So it was derived from mesencephalon. 00:15:53.300 --> 00:15:55.130 All this right here is our pons. 00:15:55.130 --> 00:15:57.090 This is all our pons. 00:15:57.090 --> 00:15:59.637 And the pons-- and this right here is the cerebellum. 00:15:59.637 --> 00:16:01.220 They were actually derived from what's 00:16:01.220 --> 00:16:03.770 called the metencephalon. 00:16:03.770 --> 00:16:05.930 And then if we look here, all the way over here, 00:16:05.930 --> 00:16:07.938 this is the medulla oblongata. 00:16:07.938 --> 00:16:09.980 And the medulla oblongata was derived from what's 00:16:09.980 --> 00:16:11.510 called the myelencephalon. 00:16:11.510 --> 00:16:13.080 So again, I'll hit it one more time. 00:16:13.080 --> 00:16:14.672 Mesencephalon. 00:16:14.672 --> 00:16:16.880 And then you got your metencephalon, which is made up 00:16:16.880 --> 00:16:19.707 of pons, and the cerebellum. 00:16:19.707 --> 00:16:21.290 And then you have your myelencephalon, 00:16:21.290 --> 00:16:23.660 which is the medulla oblongata. 00:16:23.660 --> 00:16:25.300 All right? 00:16:25.300 --> 00:16:26.570 OK. 00:16:26.570 --> 00:16:29.880 Another thing here is-- oh, I also mentioned it a little bit 00:16:29.880 --> 00:16:30.380 before. 00:16:30.380 --> 00:16:31.760 I had mentioned that all this area right here 00:16:31.760 --> 00:16:32.593 is the diencephalon. 00:16:32.593 --> 00:16:34.130 The diencephalon is mainly made up 00:16:34.130 --> 00:16:37.790 of three things, which we said thalamus, hypothalamus, 00:16:37.790 --> 00:16:39.620 and then technically the epithalamus, which 00:16:39.620 --> 00:16:40.828 consists of the pineal gland. 00:16:40.828 --> 00:16:43.420 There's this little cavity right here 00:16:43.420 --> 00:16:45.645 that also contains cerebrospinal fluid, 00:16:45.645 --> 00:16:47.270 and this is called the third ventricle. 00:16:47.270 --> 00:16:49.430 So the third ventricle would be a cavity right 00:16:49.430 --> 00:16:50.990 in this vicinity right here. 00:16:50.990 --> 00:16:54.320 So it actually gets drained from the lateral ventricle. 00:16:54.320 --> 00:16:55.820 So here's our third ventricle. 00:16:55.820 --> 00:16:57.302 The third ventricle actually drains 00:16:57.302 --> 00:16:59.510 some of that actual fluid from the lateral ventricle. 00:16:59.510 --> 00:17:02.935 Then there's another little tube right here running right here 00:17:02.935 --> 00:17:03.810 through the midbrain. 00:17:03.810 --> 00:17:05.520 So see that little tube right there? 00:17:05.520 --> 00:17:08.540 That's actually called the cerebral aqueduct. 00:17:08.540 --> 00:17:11.319 So the cerebral aqueduct drains the third ventricle, 00:17:11.319 --> 00:17:14.390 and the third ventricle drains the lateral ventricle 00:17:14.390 --> 00:17:16.460 via what's called the interventricular foramen. 00:17:16.460 --> 00:17:19.609 So again, third ventricle here and then cerebral aqueduct 00:17:19.609 --> 00:17:20.329 here. 00:17:20.329 --> 00:17:22.220 Then the cerebral aqueduct moves into what's 00:17:22.220 --> 00:17:24.482 called the fourth ventricle. 00:17:24.482 --> 00:17:25.940 And then from the fourth ventricle, 00:17:25.940 --> 00:17:27.780 the cerebrospinal fluid can go two ways. 00:17:27.780 --> 00:17:29.580 It can go down through the central canal. 00:17:29.580 --> 00:17:31.538 It will eventually go through the central canal 00:17:31.538 --> 00:17:33.470 of the spinal cord or it can go out 00:17:33.470 --> 00:17:36.830 through these two little holes called the foramen Luschka 00:17:36.830 --> 00:17:38.270 and the foramen Magendie. 00:17:38.270 --> 00:17:41.330 Or you can say foramen Magendie is the median apertures, 00:17:41.330 --> 00:17:44.210 and the foramen Luschka is the lateral apertures. 00:17:44.210 --> 00:17:45.260 OK? 00:17:45.260 --> 00:17:46.990 So that's that part there. 00:17:46.990 --> 00:17:47.720 OK. 00:17:47.720 --> 00:17:50.000 Now, if we look here in the back of the midbrain, 00:17:50.000 --> 00:17:52.480 we see these two little, like, balls there. 00:17:52.480 --> 00:17:53.270 All right? 00:17:53.270 --> 00:17:57.140 This top one right there is called the superior colliculi. 00:17:57.140 --> 00:18:00.460 And basically what he helps you to do is being able to move-- 00:18:00.460 --> 00:18:03.680 it's like a reflexive movement of your head in response 00:18:03.680 --> 00:18:05.380 to some type of visual stimulus. 00:18:05.380 --> 00:18:08.090 For example, if I see Kate Upton walking by, 00:18:08.090 --> 00:18:09.770 my head is going to move with response 00:18:09.770 --> 00:18:10.910 to that visual stimulus. 00:18:10.910 --> 00:18:12.580 Mm-mmm! 00:18:12.580 --> 00:18:15.080 And then down here is the inferior colliculi. 00:18:15.080 --> 00:18:17.630 The inferior colliculi actually controls reflexive head 00:18:17.630 --> 00:18:21.500 movements or responds to auditory stimulus. 00:18:21.500 --> 00:18:24.620 So for example, if Kate Upton's boyfriend yelled at me, hey, 00:18:24.620 --> 00:18:26.480 what you doing looking at her, my head 00:18:26.480 --> 00:18:27.980 would move that way too. 00:18:27.980 --> 00:18:30.340 So that's an example of that right there. 00:18:30.340 --> 00:18:32.972 OK, so superior colliculi, inferior colliculi there. 00:18:32.972 --> 00:18:34.430 All right, so if I look here, guys, 00:18:34.430 --> 00:18:36.305 there's another structure I want to show you. 00:18:36.305 --> 00:18:38.150 It's 182 right there. 00:18:38.150 --> 00:18:41.480 That structure right there is called the cerebral peduncles. 00:18:41.480 --> 00:18:42.560 So it's like this stalk. 00:18:42.560 --> 00:18:44.270 And again, these are projection fibers actually. 00:18:44.270 --> 00:18:46.070 So if you remember, the cerebral peduncles, 00:18:46.070 --> 00:18:47.237 these are projection fibers. 00:18:47.237 --> 00:18:48.740 They're right around the midbrain. 00:18:48.740 --> 00:18:50.510 And they carry sensory information up 00:18:50.510 --> 00:18:51.823 into the cerebrum, OK? 00:18:51.823 --> 00:18:53.990 So again, that's the cerebral peduncles right there. 00:18:53.990 --> 00:18:57.070 All right, guys, so if we look here, I have 183 right there. 00:18:57.070 --> 00:18:57.945 This is the pyramids. 00:18:57.945 --> 00:19:00.740 This is the pyramids of the medulla oblongata. 00:19:00.740 --> 00:19:02.960 That's where the descending motor fibers actually 00:19:02.960 --> 00:19:04.770 decusse, or cross, right there. 00:19:04.770 --> 00:19:05.270 OK? 00:19:05.270 --> 00:19:09.530 So the pyramids is due to the decussation, or just crossing, 00:19:09.530 --> 00:19:11.270 of the descending motor pathways. 00:19:11.270 --> 00:19:12.320 All right, guys, so if we look over here 00:19:12.320 --> 00:19:13.862 on the side of the medulla oblongata, 00:19:13.862 --> 00:19:16.220 like, on this side of this, all this pink gummy 00:19:16.220 --> 00:19:18.260 stuff, that's all the olives. 00:19:18.260 --> 00:19:21.093 And the olives are actually broken up into two nuclei. 00:19:21.093 --> 00:19:22.760 You've got their superior olivary nuclei 00:19:22.760 --> 00:19:24.685 and inferior olivary nuclei. 00:19:24.685 --> 00:19:26.060 And the superior, basically, they 00:19:26.060 --> 00:19:29.870 play a role in basically the auditory pathways. 00:19:29.870 --> 00:19:31.650 And the inferior olivary nuclei play 00:19:31.650 --> 00:19:35.295 a role within proprioception and cerebellum motor function 00:19:35.295 --> 00:19:36.670 and learning and stuff like that. 00:19:36.670 --> 00:19:36.890 OK? 00:19:36.890 --> 00:19:39.090 So again, olives play a role in proprioception, 00:19:39.090 --> 00:19:42.200 and they play a role basically in hearing also. 00:19:42.200 --> 00:19:42.950 All right? 00:19:42.950 --> 00:19:44.180 So that's your olives. 00:19:44.180 --> 00:19:45.555 Now what we're going to do, guys, 00:19:45.555 --> 00:19:47.847 is we're going to basically go over the cerebellum now. 00:19:47.847 --> 00:19:50.430 All right, guys, so if you look here, you can see all of this, 00:19:50.430 --> 00:19:52.100 like, tree-like structure right there, 00:19:52.100 --> 00:19:54.920 all this white, like, tree-like-looking thing. 00:19:54.920 --> 00:19:57.940 All this white matter here is called the arbor vitae. 00:19:57.940 --> 00:20:00.470 And the arbor vitae is just basically the white matter 00:20:00.470 --> 00:20:02.130 of the cerebellum. 00:20:02.130 --> 00:20:04.500 arbor vitae actually stands for, like, tree of life. 00:20:04.500 --> 00:20:08.100 So again, all this white matter here is the arbor vitae. 00:20:08.100 --> 00:20:11.680 And the outer gray matter on the actual edges 00:20:11.680 --> 00:20:14.180 where you'll find, like, your Purkinje cells 00:20:14.180 --> 00:20:17.000 and certain stuff like that, all the outer side 00:20:17.000 --> 00:20:19.830 is the gray matter of the cerebellar cortex. 00:20:19.830 --> 00:20:22.080 And again, that's just unmyelinated cell bodies. 00:20:22.080 --> 00:20:24.530 Again, if you look here, in the back of the cerebellum 00:20:24.530 --> 00:20:27.230 here, if you see all these little divots there, 00:20:27.230 --> 00:20:29.030 it's actually called folia. 00:20:29.030 --> 00:20:33.290 So the folia are basically like the folds of the cerebellum. 00:20:33.290 --> 00:20:35.240 OK, so all these little lines right there 00:20:35.240 --> 00:20:37.500 that you see forming these little folds, 00:20:37.500 --> 00:20:38.508 that's called the folia. 00:20:38.508 --> 00:20:40.550 All right, guys, if you look right here, right in 00:20:40.550 --> 00:20:42.470 between the actual cerebellum, there's 00:20:42.470 --> 00:20:44.750 actually this little worm-like structure between them. 00:20:44.750 --> 00:20:46.340 It's actually called the vermis. 00:20:46.340 --> 00:20:49.580 And in between the vermis, there's an actual dural septa, 00:20:49.580 --> 00:20:52.430 like I said before, that actually runs in between there. 00:20:52.430 --> 00:20:56.120 And that dural septa is actually called the falx cerebelli. 00:20:56.120 --> 00:20:58.100 The falx cerebelli. 00:20:58.100 --> 00:21:00.500 OK, again, so this structure right there between the two 00:21:00.500 --> 00:21:02.710 cerebellum is the actual vermis. 00:21:02.710 --> 00:21:04.970 And the dural septa that goes between the two 00:21:04.970 --> 00:21:07.542 is actually called the falx cerebelli. 00:21:07.542 --> 00:21:09.750 All right, so that pretty much covers the cerebellum. 00:21:09.750 --> 00:21:10.370 Now what we're going to do is we're 00:21:10.370 --> 00:21:12.080 going to move on to the cranial nerves. 00:21:12.080 --> 00:21:14.780 So if we look right here, we're going to see cranial nerve one. 00:21:14.780 --> 00:21:15.998 That's the olfactory nerve. 00:21:15.998 --> 00:21:18.290 And again, remember that the olfactory nerve originates 00:21:18.290 --> 00:21:22.760 in the nasal cavity through the olfactory epithelium, 00:21:22.760 --> 00:21:25.250 and that actually picks up certain types of sensations 00:21:25.250 --> 00:21:28.450 like smell from odorants in different types of chemicals 00:21:28.450 --> 00:21:30.200 and carries that up through the cribriform 00:21:30.200 --> 00:21:34.670 plate of the ethmoid bone and then up into-- 00:21:34.670 --> 00:21:36.740 specifically up into this olfactory bulb here 00:21:36.740 --> 00:21:39.520 where there's glomeruli and mitral cells. 00:21:39.520 --> 00:21:41.207 OK, so he's a sensory nerve. 00:21:41.207 --> 00:21:43.790 Then right here, you're going to notice two optic nerves right 00:21:43.790 --> 00:21:44.030 there. 00:21:44.030 --> 00:21:45.450 So there's your left optic nerve. 00:21:45.450 --> 00:21:47.090 There's your right optic nerve. 00:21:47.090 --> 00:21:48.980 And then the point in which they cross 00:21:48.980 --> 00:21:51.030 is called the optic chiasma. 00:21:51.030 --> 00:21:51.530 OK? 00:21:51.530 --> 00:21:53.270 And so the optic nerve is-- 00:21:53.270 --> 00:21:55.700 basically picks up sensations of vision. 00:21:55.700 --> 00:21:58.100 So he picks up the vision stimulus 00:21:58.100 --> 00:22:00.710 and then takes that into the actual cerebrum, 00:22:00.710 --> 00:22:04.180 specifically to that primary visual cortex. 00:22:04.180 --> 00:22:06.825 Then we're going to have to go and separate this guy 00:22:06.825 --> 00:22:08.700 so we can look at some other structures here, 00:22:08.700 --> 00:22:10.658 so we look at the midbrain a little bit deeper. 00:22:10.658 --> 00:22:12.158 All right, guys, so if we look here, 00:22:12.158 --> 00:22:13.430 we can see cranial nerve 3. 00:22:13.430 --> 00:22:16.660 It actually comes out in between the interpeduncular fossa 00:22:16.660 --> 00:22:18.050 right there at the midbrain. 00:22:18.050 --> 00:22:20.330 That's called the oculomotor nerve, cranial nerve 3. 00:22:20.330 --> 00:22:21.860 The oculomotor nerve actually runs 00:22:21.860 --> 00:22:24.230 through the superior orbital fissure 00:22:24.230 --> 00:22:27.410 and supplies a lot of the extraocular eye muscles. 00:22:27.410 --> 00:22:29.750 I also didn't mention the hole that the optic nerve runs 00:22:29.750 --> 00:22:31.580 through, but you can imagine it's the optic canal. 00:22:31.580 --> 00:22:34.280 So again, oculomotor nerve runs through the superior orbital 00:22:34.280 --> 00:22:38.330 fissure and supplies a lot of extraocular eye muscles. 00:22:38.330 --> 00:22:40.610 Then if we come down here, we can see this little-- 00:22:40.610 --> 00:22:42.693 you see this little white thing right there, guys? 00:22:42.693 --> 00:22:45.740 The little white piece of thing popping down there? 00:22:45.740 --> 00:22:47.810 That's called the trochlear nerve. 00:22:47.810 --> 00:22:51.260 So that's called trochlear nerve, or cranial nerve 4. 00:22:51.260 --> 00:22:54.470 And the cranial nerve 4, or the trochlear nerve, 00:22:54.470 --> 00:22:57.740 actually runs also through the superior orbital fissure 00:22:57.740 --> 00:22:58.803 and supplies the-- 00:22:58.803 --> 00:23:00.470 it's called the superior oblique muscle. 00:23:00.470 --> 00:23:02.435 It's just another extraocular eye muscle. 00:23:02.435 --> 00:23:04.820 OK, so he plays a role in motor functioning. 00:23:04.820 --> 00:23:06.200 All right, so here's the trochlear nerve again, right? 00:23:06.200 --> 00:23:07.160 So that's cranial nerve 4. 00:23:07.160 --> 00:23:09.440 And then if you look down here, we have these two nerves, 00:23:09.440 --> 00:23:10.290 because they're paired, guys. 00:23:10.290 --> 00:23:12.290 So we're going to see the trigeminal nerve here, 00:23:12.290 --> 00:23:13.400 which is cranial nerve 5. 00:23:13.400 --> 00:23:15.108 And you'll see the trigeminal nerve here, 00:23:15.108 --> 00:23:16.590 which is, again, cranial nerve 5. 00:23:16.590 --> 00:23:19.460 So the trigeminal nerve is a really big one, 00:23:19.460 --> 00:23:23.150 and it actually splits into three branches. 00:23:23.150 --> 00:23:25.430 And it actually runs through three holes. 00:23:25.430 --> 00:23:27.620 It can run through the superior orbital fissure. 00:23:27.620 --> 00:23:31.580 It can run through the foramen ovale and the foramen rotondum. 00:23:31.580 --> 00:23:33.860 And the trigeminal nerve supplies the muscles 00:23:33.860 --> 00:23:36.680 of mastication, and he also supplies 00:23:36.680 --> 00:23:40.680 certain areas of the skin of the face to pick up sensations. 00:23:40.680 --> 00:23:43.640 So he plays a role in muscle action, which is mastication, 00:23:43.640 --> 00:23:44.810 chewing. 00:23:44.810 --> 00:23:48.445 And he also picks up sensations on the face. 00:23:48.445 --> 00:23:49.820 Interestingly, this is actually-- 00:23:49.820 --> 00:23:51.590 if this has what's called neuralgia, 00:23:51.590 --> 00:23:54.200 trigeminal neuralgia, where there's 00:23:54.200 --> 00:23:56.570 some certain type of nerve pain, this 00:23:56.570 --> 00:23:59.810 can cause one of the most severe nerve pains actually known 00:23:59.810 --> 00:24:00.380 to man. 00:24:00.380 --> 00:24:02.510 It's actually called trigeminal neuralgia. 00:24:02.510 --> 00:24:05.950 And it's extremely, extremely painful. 00:24:05.950 --> 00:24:08.930 They actually call it the suicide . disease. 00:24:08.930 --> 00:24:11.360 All right, then if we come down here to this structure 00:24:11.360 --> 00:24:13.500 right there and that structure right there, 00:24:13.500 --> 00:24:17.090 these are actually your cranial nerve 6, or the abducens nerve. 00:24:17.090 --> 00:24:19.640 And he also runs through the superior orbital fissure. 00:24:19.640 --> 00:24:22.850 And he supplies the lateral rectus. 00:24:22.850 --> 00:24:26.270 And again, that's another extraocular eye muscle. 00:24:26.270 --> 00:24:28.770 Then if we move out laterally over here, 00:24:28.770 --> 00:24:31.130 we're going to have these two guys-- see this one right 00:24:31.130 --> 00:24:34.550 there and this one over here. 00:24:34.550 --> 00:24:36.990 That's actually called the facial nerve. 00:24:36.990 --> 00:24:38.100 So that's cranial nerve 7. 00:24:38.100 --> 00:24:41.920 So this one right there and this one right there, OK? 00:24:41.920 --> 00:24:45.890 And the facial nerve has five branches. 00:24:45.890 --> 00:24:50.760 But he can run through the stylomastoid, foramen. 00:24:50.760 --> 00:24:54.230 And he also can run through the internal acoustic meatus. 00:24:54.230 --> 00:25:00.050 But basically he supplies the muscles of facial expression, 00:25:00.050 --> 00:25:03.350 a lot of glands within the-- like the lacrimal gland 00:25:03.350 --> 00:25:06.290 and nasal glands and stuff like that. 00:25:06.290 --> 00:25:09.050 So he plays a role in both-- 00:25:09.050 --> 00:25:11.900 and he also picks up sensations again from the face as well. 00:25:11.900 --> 00:25:15.890 So he's actually a motor nerve and a sensory nerve. 00:25:15.890 --> 00:25:16.390 OK? 00:25:16.390 --> 00:25:18.860 So that's the facial nerve. 00:25:18.860 --> 00:25:20.810 Then if we go over here to the edge, 00:25:20.810 --> 00:25:23.300 that one right there over there and this one right there 00:25:23.300 --> 00:25:26.960 on that edge, that is actually called the vestibulocochlear 00:25:26.960 --> 00:25:27.560 nerve. 00:25:27.560 --> 00:25:30.410 And the vestibulocochlear nerve, he also 00:25:30.410 --> 00:25:32.780 runs through the internal acoustic meatus. 00:25:32.780 --> 00:25:38.090 And he basically carries dynamic and static equilibrium and just 00:25:38.090 --> 00:25:40.070 general sound and hearing. 00:25:40.070 --> 00:25:42.183 And that's that guy. 00:25:42.183 --> 00:25:43.600 Then if we come down here, there's 00:25:43.600 --> 00:25:46.520 this little chunk right there, which 00:25:46.520 --> 00:25:49.250 is the same chunk right there. 00:25:49.250 --> 00:25:51.270 That's called the glossopharyngeal nerve, 00:25:51.270 --> 00:25:52.910 which is cranial nerve 9. 00:25:52.910 --> 00:25:58.640 And he actually runs through the jugular foramen, 00:25:58.640 --> 00:26:00.710 and he supplies the tongue. 00:26:00.710 --> 00:26:03.440 He supplies certain muscles of the pharynx. 00:26:03.440 --> 00:26:06.320 He also can act as-- he can pick up sensations 00:26:06.320 --> 00:26:07.570 from the baroreceptors. 00:26:07.570 --> 00:26:10.520 So he plays a lot of roles in different sensory and motor 00:26:10.520 --> 00:26:11.680 functions as well. 00:26:11.680 --> 00:26:12.180 OK? 00:26:12.180 --> 00:26:14.850 Below him is the vagus nerve. 00:26:14.850 --> 00:26:18.140 So this one right there and this one right there. 00:26:18.140 --> 00:26:19.380 That's cranial nerve 10. 00:26:19.380 --> 00:26:22.490 So again, vagus nerve right there and right there. 00:26:22.490 --> 00:26:25.850 He is the main parasympathetic nerve, OK? 00:26:25.850 --> 00:26:30.020 He carries about 90% of the parasympathetic flow. 00:26:30.020 --> 00:26:32.090 And he also runs through the jugular foramen, 00:26:32.090 --> 00:26:34.430 and he supplies many, many different organs 00:26:34.430 --> 00:26:36.920 from the heart to the lungs to the GI tract 00:26:36.920 --> 00:26:39.990 to the urogenital tract, so on and so forth. 00:26:39.990 --> 00:26:43.017 So again, that's your vagus nerve. 00:26:43.017 --> 00:26:44.600 So if you look down here, guys, you'll 00:26:44.600 --> 00:26:47.490 see this nerve right here and over here. 00:26:47.490 --> 00:26:50.810 It's cranial nerve 11, which is called the accessory nerve. 00:26:50.810 --> 00:26:53.177 Now, the accessory nerve has two parts. 00:26:53.177 --> 00:26:55.010 One of them actually is on the cervical part 00:26:55.010 --> 00:26:57.620 of the spinal cord and one on this medulla 00:26:57.620 --> 00:26:59.510 here, like the medullary branch. 00:26:59.510 --> 00:27:02.630 And what happens is the cervical branch of the accessory nerve 00:27:02.630 --> 00:27:04.790 comes up through the foramen magnum 00:27:04.790 --> 00:27:07.700 and merges with this branch off the medulla. 00:27:07.700 --> 00:27:11.240 And as a collection, they run through the jugular foramen. 00:27:11.240 --> 00:27:14.780 And they go and supply the trapezius muscle 00:27:14.780 --> 00:27:16.430 and the sternocleidomastoid, which 00:27:16.430 --> 00:27:19.900 are, again, those somatic muscles or skeletal muscle. 00:27:19.900 --> 00:27:21.950 All right, so that's the accessory nerve. 00:27:21.950 --> 00:27:24.020 So he's mainly a motor nerve. 00:27:24.020 --> 00:27:26.450 And then the last one right here is this guy right there, 00:27:26.450 --> 00:27:28.200 which is the same as this guy right there. 00:27:28.200 --> 00:27:32.140 And that's cranial nerve 12, which is the hypoglossal nerve. 00:27:32.140 --> 00:27:33.590 And the hypoglossal nerve actually 00:27:33.590 --> 00:27:35.900 runs through what's called the hypoglossal canal 00:27:35.900 --> 00:27:38.750 and supplies some of the extrinsic muscles 00:27:38.750 --> 00:27:40.420 of the tongue. 00:27:40.420 --> 00:27:41.240 OK? 00:27:41.240 --> 00:27:42.560 So he's mainly a motor nerve. 00:27:42.560 --> 00:27:44.060 All right, guys, so that pretty much 00:27:44.060 --> 00:27:45.740 covers all the cranial nerves. 00:27:45.740 --> 00:27:47.390 I hope this video helped, guys. 00:27:47.390 --> 00:27:50.220 And see you, ninja nerds.