WEBVTT 00:00.000 --> 00:30.000 position:50% align:top line:0% *This machine-generated transcript may have errors. If remediation or a manually-generated transcript is needed, please contact NLM Support at https://support.nlm.nih.gov.* 00:30.540 --> 00:30.750 Mhm. 00:31.140 --> 00:34.060 In this program we will examine discuss 00:34.140 --> 00:37.060 the microscopic and the light microscopic appearance of 00:37.060 --> 00:39.150 selected portions of the gi tract 00:39.940 --> 00:42.870 objectives for this program may be found in the accompanying 00:42.870 --> 00:43.660 study guide. 00:45.040 --> 00:47.460 This cross sectional diagram 00:48.240 --> 00:50.850 Shows the four basic layers 00:51.540 --> 00:53.060 of the gi tract 00:54.840 --> 00:56.760 First the mucosa, 00:58.640 --> 00:59.750 the sub mucosa, 01:01.740 --> 01:03.860 muscular as external, 01:04.340 --> 01:05.480 and the cirrhosis 01:07.040 --> 01:09.530 variations on this basic plan can help 01:09.530 --> 01:12.350 identify the specific area of the gi tract. 01:12.360 --> 01:13.180 Understudy. 01:14.530 --> 01:16.850 This drawing is divided Into two sections. 01:16.950 --> 01:18.460 The left side 01:19.240 --> 01:20.760 represents the 01:21.540 --> 01:24.060 characteristic structure of the small intestine. 01:24.630 --> 01:27.190 The right side represents a section of the 01:27.190 --> 01:29.910 colon beginning on 01:29.910 --> 01:31.460 the Luminal side. 01:32.440 --> 01:35.330 We see the covering epithelium which 01:35.330 --> 01:38.150 may be either stratified squamous or 01:38.320 --> 01:40.970 simple kilometer epithelium depending upon 01:40.970 --> 01:42.060 the area 01:43.640 --> 01:45.880 immediately underline the 01:46.080 --> 01:46.960 epithelium. 01:47.440 --> 01:49.880 We have a loose connective tissue layer 01:49.880 --> 01:52.660 termed the lamb inappropriate. 01:54.540 --> 01:57.320 The next layer contains smooth 01:57.320 --> 02:00.160 muscle and it's called the 02:00.160 --> 02:01.950 muscular eras mucosa. 02:03.940 --> 02:06.250 These three layers together 02:07.040 --> 02:08.660 I called the mucosa. 02:10.340 --> 02:13.190 Next there's a layer of connective tissue, 02:13.190 --> 02:15.870 the sub mucosa and within the sub 02:15.870 --> 02:18.360 mucosa there's a group of 02:19.040 --> 02:21.600 nerve cells and bundles of nerve fibers 02:22.020 --> 02:24.490 termed the mice ners 02:24.510 --> 02:25.250 plexus. 02:28.040 --> 02:30.990 The next layer is usually made up of 02:30.990 --> 02:33.700 smooth muscle but may under 02:33.700 --> 02:36.590 certain conditions be made up of skeletal 02:36.590 --> 02:37.070 muscle. 02:37.300 --> 02:39.780 This layer is termed the 02:39.780 --> 02:41.030 muscular rose X. 02:41.030 --> 02:43.330 Turn up and generally 02:43.330 --> 02:45.260 consists of an inner circular 02:47.140 --> 02:49.960 and an outer longitudinal layer. 02:51.540 --> 02:54.200 There is a group of nerve cells and 02:54.200 --> 02:57.000 fibers located within the muscular sex terna 02:57.120 --> 02:58.990 termed the our box 02:59.640 --> 03:00.270 plexus. 03:02.640 --> 03:05.340 Both the meisters and our 03:05.340 --> 03:07.760 box plexus is formed the 03:07.770 --> 03:10.100 intrinsic nerve supply of the 03:10.100 --> 03:11.350 intestinal wall 03:12.640 --> 03:14.860 immediately outside of the 03:15.640 --> 03:17.230 must get rs external. 03:17.230 --> 03:19.560 We see a layer of connective tissue 03:20.340 --> 03:22.760 with a covering mesophyll idea layer. 03:23.140 --> 03:25.450 This is termed the cirrhosis. 03:29.340 --> 03:31.050 On the left side. 03:31.640 --> 03:34.160 We see mucosal glands 03:36.840 --> 03:39.350 and projections of the 03:39.600 --> 03:42.080 lamb inappropriate characteristic of the small 03:42.080 --> 03:42.660 intestine. 03:43.620 --> 03:46.260 These projections are termed Valli. 03:51.040 --> 03:51.820 In addition, 03:52.040 --> 03:54.360 we see sub mucosal folds, 03:55.940 --> 03:58.010 term clicky circular areas. 04:02.240 --> 04:04.390 We also see large ducks 04:05.340 --> 04:06.660 penetrating the wall 04:08.740 --> 04:11.230 like those coming from the pancreas. 04:11.640 --> 04:14.330 Then after their secretions into the gi 04:14.330 --> 04:15.060 tract, 04:16.140 --> 04:18.860 we also see sub mucosal glands 04:19.440 --> 04:21.660 characteristic of the duodenum. 04:24.240 --> 04:26.430 The right side represents a 04:26.430 --> 04:29.350 section of the colon with the 04:29.350 --> 04:30.760 lymphatic tissue, 04:31.440 --> 04:33.060 and there are no. 04:33.740 --> 04:34.460 They live. 04:36.640 --> 04:39.060 Now let's look at a series of slides 04:39.440 --> 04:41.860 of the gi tract beginning with the lip. 04:46.040 --> 04:48.750 This is the all side, 04:50.240 --> 04:51.050 all the lip. 04:51.640 --> 04:54.160 We see a thickened 04:54.940 --> 04:56.180 non carotene eyes, 04:56.180 --> 04:57.850 stratified squamous epithelium. 04:58.940 --> 05:01.890 As we move around 05:01.890 --> 05:03.560 the edge 05:05.440 --> 05:06.360 of the lip, 05:12.640 --> 05:15.350 we see the transition at this point 05:15.940 --> 05:16.890 to the carotene. 05:16.890 --> 05:17.450 Ized, 05:17.460 --> 05:19.360 stratified squamous epithelium 05:20.840 --> 05:22.960 with numerous hair follicles, 05:24.840 --> 05:27.680 and associated sebaceous glands. 05:31.100 --> 05:32.060 In this area 05:34.650 --> 05:37.100 we see numerous mucous 05:37.100 --> 05:37.780 glands, 05:42.540 --> 05:44.850 as well as the 05:46.620 --> 05:48.190 skeletal muscle fibers 05:49.340 --> 05:52.100 present within the 05:52.110 --> 05:54.460 obituaries Oris muscle. 05:58.740 --> 06:00.370 As we can see in this 06:03.140 --> 06:04.060 area here. 06:07.740 --> 06:08.000 Well, 06:08.000 --> 06:10.910 next demonstrate three types of pili 06:10.920 --> 06:13.760 with three different slides of the tongue. 06:25.040 --> 06:27.440 The first slide shows the fill, 06:27.440 --> 06:28.760 a form capelli. 06:29.540 --> 06:32.050 On the surface we see 06:32.050 --> 06:33.930 the carrot, 06:33.930 --> 06:34.620 ionized, 06:34.730 --> 06:36.960 stratified squamous epithelium 06:38.040 --> 06:40.350 with an underlying lamb inappropriate. 06:41.940 --> 06:44.920 We see that the lamb inappropriate is thrown 06:44.920 --> 06:47.750 into basil folds to 06:47.750 --> 06:49.760 reflect it as surface 06:50.240 --> 06:51.160 projections. 06:52.540 --> 06:54.850 These folds are 06:54.850 --> 06:56.560 called happily. 06:58.340 --> 07:00.980 There are elevations are both connective tissue and the 07:00.980 --> 07:01.760 epithelium. 07:02.740 --> 07:05.550 There may be smaller projections, 07:07.740 --> 07:09.590 connective tissue in the epithelium, 07:09.590 --> 07:11.160 resulting in secondary, 07:11.640 --> 07:14.620 properly on 07:14.620 --> 07:16.040 the surface of the epithelium. 07:16.040 --> 07:17.350 We could see threadlike 07:18.640 --> 07:21.530 projections of the stratified squamous epithelium, 07:21.530 --> 07:24.360 which contains a small core of connective tissue. 07:25.140 --> 07:27.990 These projections are termed the fill a 07:27.990 --> 07:29.460 form happily 07:43.730 --> 07:44.250 the years. 07:44.250 --> 07:47.110 Capelli do not 07:47.110 --> 07:48.890 contain taste buds. 07:50.240 --> 07:51.950 We can also now see 07:53.140 --> 07:54.360 skeletal muscle 07:55.540 --> 07:57.820 fibers arranged in a very 07:57.820 --> 08:00.610 characteristic criss cross 08:00.700 --> 08:02.960 pattern within the substance of the tongue. 08:05.140 --> 08:07.580 On the next slide we see foliate 08:07.590 --> 08:08.160 papillae. 08:08.940 --> 08:11.850 They are more common in certain rodents than man, 08:12.340 --> 08:14.830 but do resemble the fungi form 08:15.000 --> 08:15.580 Papillion, 08:15.590 --> 08:16.060 man. 08:17.240 --> 08:19.690 The foliate capelli, 08:21.940 --> 08:23.260 our dome shaped 08:25.040 --> 08:27.090 and are more dome shaped than the fill, 08:27.090 --> 08:27.950 a form papillae, 08:28.940 --> 08:30.760 note that the secondary 08:31.640 --> 08:33.650 projections of connective tissue 08:34.840 --> 08:37.540 are not reflected by the covering 08:37.580 --> 08:38.460 epithelium. 08:39.440 --> 08:40.250 Therefore, 08:40.260 --> 08:43.030 the vascular supply is brought in 08:43.030 --> 08:45.290 very close contact to the 08:45.290 --> 08:46.920 outside surface. 08:47.410 --> 08:50.370 This creates a pinkish appearance in the living 08:50.370 --> 08:50.920 state. 08:52.440 --> 08:54.150 In the substance of the tongue, 08:57.440 --> 08:59.450 we see that there are 09:03.240 --> 09:05.520 large groups of syria's 09:05.530 --> 09:06.400 glands, 09:06.410 --> 09:09.050 which are termed the glands of von 09:09.050 --> 09:09.450 Ebner. 09:15.140 --> 09:17.360 On the lateral border 09:19.640 --> 09:21.070 of the people, 09:21.540 --> 09:23.880 we see the lighter stained areas 09:24.640 --> 09:26.760 which are the taste buds. 09:28.840 --> 09:29.050 Mhm. 09:36.240 --> 09:37.260 Now in this field 09:39.740 --> 09:42.650 we see first the 09:42.650 --> 09:43.250 opening 09:46.340 --> 09:47.620 all of the taste buds, 09:47.630 --> 09:49.360 which is called the taste poor. 09:51.440 --> 09:54.200 We see that there are two general cell 09:54.200 --> 09:56.960 types within the taste buds. 09:58.640 --> 10:01.460 First there would be the 10:01.930 --> 10:02.860 supporting 10:07.030 --> 10:09.610 sustain tacular cells which 10:09.610 --> 10:11.950 contain lightly stained nuclei 10:12.740 --> 10:15.480 and are arranged like staves of a barrel, 10:15.490 --> 10:17.960 around the taste poor 10:19.240 --> 10:22.150 between the substance of the cells. 10:22.740 --> 10:24.060 Our darker stained 10:25.240 --> 10:26.950 neural epithelial cells. 10:31.240 --> 10:34.110 On the next slide we'll examine the validate 10:34.240 --> 10:34.810 happily. 10:36.340 --> 10:38.000 On our low power objective, 10:38.010 --> 10:40.150 we see that the valid happily 10:41.340 --> 10:44.160 tends to be recessed below the surface of the town, 10:45.140 --> 10:47.960 therefore they frequently appear to be isolated. 10:49.210 --> 10:51.630 It is important to remember that they do 10:51.640 --> 10:53.660 open to the surface of the tongue. 10:54.840 --> 10:57.470 Note the general characteristics of the 10:57.480 --> 11:00.450 tongue with the covering 11:00.550 --> 11:01.360 epithelium, 11:03.640 --> 11:05.650 the underlying connective tissue, 11:07.940 --> 11:09.160 skeletal muscle 11:12.140 --> 11:14.750 and the serious glands 11:23.040 --> 11:25.570 notice on the lateral surface 11:26.540 --> 11:27.760 of the validate. 11:28.140 --> 11:31.000 Hopefully the 11:31.000 --> 11:31.860 taste buds 11:35.440 --> 11:37.750 as we continue down the gi tract, 11:37.750 --> 11:40.550 we will next Examine The Upper 1/3 of the 11:40.550 --> 11:41.410 Esophagus. 11:43.020 --> 11:45.910 This is a macroscopic cross sectional 11:45.910 --> 11:48.280 view of the esophagus. 11:48.840 --> 11:51.680 If we began on the Luminal 11:51.680 --> 11:52.350 side, 11:54.040 --> 11:56.660 we can see first the 11:56.660 --> 11:57.550 epithelium, 12:02.040 --> 12:04.860 the underlying lamb inappropriate, 12:06.940 --> 12:08.650 The sub mucosa 12:10.140 --> 12:12.420 and the outer more darkly 12:12.420 --> 12:14.400 sustained muscular areas. 12:14.770 --> 12:15.350 External. 12:19.040 --> 12:20.730 We're on our low power objective. 12:20.730 --> 12:21.760 On the microscope. 12:23.040 --> 12:25.460 Beginning on the Luminal side, 12:26.640 --> 12:29.580 we see the covering non 12:29.580 --> 12:30.130 carotene. 12:30.130 --> 12:32.730 Ized stratified squamous 12:32.730 --> 12:33.460 epithelium. 12:34.940 --> 12:37.470 Next we see the connective tissue layer, 12:37.470 --> 12:38.750 the lamb inappropriate, 12:39.440 --> 12:42.050 followed by a smooth muscle layer 12:43.540 --> 12:45.800 termed the muscular as 12:46.000 --> 12:46.750 mucosa. 12:48.540 --> 12:50.560 Outside of the muscular S. 12:50.560 --> 12:51.260 Mucosa, 12:51.640 --> 12:53.260 we see the sub mucosa, 12:56.440 --> 12:59.010 another connective tissue layer containing 12:59.020 --> 13:00.060 blood vessels. 13:01.240 --> 13:01.440 Yeah, 13:04.220 --> 13:05.890 and connective tissue fibers. 13:07.340 --> 13:09.670 As we move to the 13:09.670 --> 13:11.150 muscularity external, 13:13.140 --> 13:14.760 we see that the 13:15.540 --> 13:17.360 muscle and skeletal muscle 13:21.140 --> 13:23.560 with the characteristic 13:23.940 --> 13:24.860 peripheral 13:27.240 --> 13:30.240 nuclei the presence of 13:30.240 --> 13:32.730 skeletal muscle and the muscular sex turner is 13:32.730 --> 13:34.650 evidence that this is the upper 13:35.040 --> 13:37.140 1/3 of the Esophagus. 13:40.440 --> 13:43.250 Next we will examine the lower 1/3 of the 13:43.250 --> 13:44.100 esophagus. 13:45.740 --> 13:48.350 As we began on the Luminal side, 13:48.740 --> 13:50.750 we see again a non 13:51.240 --> 13:51.790 carotene. 13:51.790 --> 13:54.660 Ized stratified squamous epithelium 13:55.740 --> 13:57.910 with its underlying lamb 13:57.910 --> 13:58.760 inappropriate. 14:02.640 --> 14:03.450 We see 14:05.640 --> 14:08.430 below that the muscular 14:08.430 --> 14:08.870 areas, 14:09.720 --> 14:10.450 mucosa 14:13.040 --> 14:14.150 and a very thin 14:15.840 --> 14:18.680 underlying sub mucosal connective 14:18.690 --> 14:19.650 tissue layer. 14:20.940 --> 14:23.390 As we move to the muscular is 14:23.550 --> 14:24.360 external, 14:25.040 --> 14:27.560 we see that it consists of an inner 14:28.240 --> 14:29.460 circular layer 14:31.340 --> 14:34.060 and an outer longitudinal 14:34.060 --> 14:36.450 layer of smooth muscle. 14:44.040 --> 14:45.110 On high power. 14:45.380 --> 14:47.740 We can now see a junction all area 14:47.740 --> 14:50.660 between the inner circular 14:51.640 --> 14:52.960 seen in cross section 14:56.310 --> 14:58.390 and the outer longitudinal 15:00.540 --> 15:03.530 layers of smooth muscle fibers During 15:03.530 --> 15:06.470 contrast to the skeletal muscle fibers 15:06.640 --> 15:09.460 of the Upper 1/3 of the Esophagus. 15:10.640 --> 15:12.880 To distinguish between the upper third, 15:12.880 --> 15:15.420 one third and the lower third of the 15:15.420 --> 15:16.250 esophagus. 15:16.640 --> 15:19.140 One must examine the type of muscle 15:19.140 --> 15:22.060 present within the muscular as external. 15:23.540 --> 15:26.260 There is skeletal muscle present in the upper part, 15:27.140 --> 15:29.960 A blending of the two types in the middle 15:29.960 --> 15:32.890 3rd and a predominance of smooth 15:32.890 --> 15:35.510 muscle in the 15:35.600 --> 15:36.560 lower part. 15:40.340 --> 15:41.290 As we continue, 15:41.290 --> 15:43.720 we will examine the junction all area between the 15:43.720 --> 15:45.650 esophagus and the stomach. 15:47.440 --> 15:50.260 On our low power objective we can see 15:50.260 --> 15:53.160 the abrupt transition between 15:53.740 --> 15:54.910 the esophagus 15:57.090 --> 15:58.660 and the stomach. 16:03.740 --> 16:06.650 We can see the stratified squamous epithelium, 16:06.840 --> 16:08.980 non character knives to the esophagus 16:09.740 --> 16:10.850 and in this area 16:12.340 --> 16:15.310 the simple 16:15.530 --> 16:18.330 kilometer epithelial lining of the 16:18.330 --> 16:20.960 cardiac portion of the stomach. 16:23.540 --> 16:26.010 Note the presence of glands 16:28.340 --> 16:31.150 within the lamb inappropriate of the 16:31.150 --> 16:31.660 stomach. 16:35.140 --> 16:36.960 These may be either simple 16:38.640 --> 16:41.090 or compound tubular types of lands and 16:41.090 --> 16:43.780 generally function to secrete 16:43.780 --> 16:44.360 mucus. 16:45.540 --> 16:48.140 They have little impact on the total 16:48.140 --> 16:49.850 function of the stomach. 16:54.120 --> 16:56.700 The following slide is from the funders of the 16:56.700 --> 16:57.160 stomach. 16:59.840 --> 17:02.770 This is a microscopic view We 17:02.770 --> 17:05.700 see first what appears to be a very 17:05.700 --> 17:06.170 thick 17:08.140 --> 17:08.950 epithelium. 17:10.740 --> 17:13.670 In fact this area consists of glandular 17:14.140 --> 17:15.760 in folding from the surface. 17:17.440 --> 17:19.660 We can also see large 17:20.230 --> 17:22.770 sub mucosal folds which in the stomach 17:23.340 --> 17:24.860 are termed Rudy. 17:27.040 --> 17:29.450 To the outside we can 17:29.450 --> 17:31.820 see the muscular us 17:33.040 --> 17:33.760 external. 17:35.940 --> 17:38.680 And before proceeding to the microscopic study of this 17:38.680 --> 17:41.360 slide we will examine a diagram 17:41.840 --> 17:44.340 are the characteristic gastric 17:44.350 --> 17:45.240 glands. 17:47.140 --> 17:49.690 This diagram shows the gastric 17:49.690 --> 17:52.230 gland which is divided into four 17:52.240 --> 17:53.560 basic parts. 17:54.640 --> 17:56.770 Beginning on the surface 17:59.640 --> 18:01.260 we see the covering 18:02.240 --> 18:05.120 service epithelial cells and 18:05.120 --> 18:06.400 the imaginations 18:09.040 --> 18:11.900 of the apathy ideal surface which is termed the 18:11.900 --> 18:12.360 pit. 18:16.430 --> 18:19.270 Second we see an area 18:20.440 --> 18:21.400 it contains 18:23.240 --> 18:24.010 the isthmus. 18:26.340 --> 18:29.270 It has pink staining parietal 18:29.270 --> 18:29.960 cells 18:32.940 --> 18:35.670 and the surface epithelial cells. 18:37.240 --> 18:40.060 Below this we 18:40.060 --> 18:42.060 see the neck of the gland, 18:42.640 --> 18:45.320 which again contains the ready 18:45.320 --> 18:47.120 stained parietal cells 18:47.740 --> 18:50.260 and the 18:50.260 --> 18:50.840 mucus. 18:50.900 --> 18:51.960 Next cells 18:56.240 --> 18:58.760 in the deepest portion of the gland 19:01.240 --> 19:03.990 we see the base of the gland containing again 19:03.990 --> 19:05.350 parietal cells 19:06.840 --> 19:09.530 and the base of filic zima 19:09.530 --> 19:11.060 genic cells. 19:20.840 --> 19:23.380 We are now on the low power objectives with the 19:23.380 --> 19:24.670 funding of the stomach. 19:25.240 --> 19:28.050 Take special note of the very 19:28.050 --> 19:30.630 thick mucosa which 19:30.630 --> 19:32.990 contains numerous 19:33.000 --> 19:33.960 glands 19:38.040 --> 19:39.660 changing to her high power. 19:43.440 --> 19:44.550 On the surface 19:47.240 --> 19:50.160 we see the surface epithelial 19:50.160 --> 19:50.770 cells 19:53.540 --> 19:55.270 and the pit. 19:58.840 --> 20:01.610 Below this we see 20:01.960 --> 20:04.960 several piggy stain cells 20:06.240 --> 20:08.360 term the parietal cells 20:09.640 --> 20:12.370 that will in combination with the 20:12.370 --> 20:14.670 surface epithelial cells 20:15.540 --> 20:17.420 comprise the isthmus. 20:21.340 --> 20:24.270 Below this we 20:24.270 --> 20:27.060 begin to pick up the parietal cells 20:28.640 --> 20:30.770 and more darkly stained 20:31.940 --> 20:34.850 cells which are termed the mucus Next 20:34.850 --> 20:35.450 cells 20:38.240 --> 20:40.980 This area would be the neck of the 20:40.980 --> 20:41.460 gland. 20:45.740 --> 20:46.970 In the deeper areas 20:50.540 --> 20:52.670 we see basa filic cells 20:53.740 --> 20:56.550 two term the zimet and cells 20:57.640 --> 21:00.360 with occasional parietal cells 21:02.840 --> 21:05.590 immediately below 21:05.840 --> 21:06.710 the glands. 21:08.840 --> 21:10.270 We see a very thin 21:11.240 --> 21:12.860 muscular mucosa 21:15.540 --> 21:17.060 and then the underlying 21:18.140 --> 21:19.160 seven mucosa 21:22.140 --> 21:23.890 note in this area, 21:23.900 --> 21:26.630 the presence of fibers of my 21:26.630 --> 21:27.960 sinners plexus. 21:34.840 --> 21:36.060 To the outside, 21:37.840 --> 21:40.660 we can now begin to see beginning of 21:40.660 --> 21:42.850 the muscular sx turn up 21:44.840 --> 21:46.270 containing smooth muscle 21:48.540 --> 21:51.480 and in this case showing the characteristic inner 21:51.590 --> 21:52.350 circular 21:55.140 --> 21:57.560 and to the outside 22:00.540 --> 22:03.170 the outer longitudinal layers. 22:05.040 --> 22:07.440 In some places within the 22:07.440 --> 22:08.060 stomach, 22:08.240 --> 22:10.920 you may see an additional circular 22:10.920 --> 22:11.350 layer. 22:12.040 --> 22:12.270 Okay, 22:13.240 --> 22:15.800 note in this area the 22:15.800 --> 22:18.510 presence of fibers of the our 22:18.510 --> 22:20.070 box plexus. 22:28.040 --> 22:30.700 We will continue our examination of the gi 22:30.700 --> 22:33.260 tract with the polaris of the stomach 22:35.040 --> 22:36.280 On our 10 x. 22:36.280 --> 22:37.260 objective. 22:37.410 --> 22:39.170 Take note of the very deep 22:41.240 --> 22:43.020 and elongate pits 22:44.440 --> 22:45.790 within the polaris. 22:46.640 --> 22:49.320 The pets are lined by surface 22:49.320 --> 22:50.660 epithelial cells. 22:51.840 --> 22:54.440 Note that these extend down at least 22:54.440 --> 22:57.190 halfway through the mucosal 22:57.360 --> 22:57.860 layer. 23:00.440 --> 23:01.670 In the basal area, 23:03.040 --> 23:05.640 the glands become coiled and contain 23:05.640 --> 23:07.360 mucus producing cells. 23:08.440 --> 23:11.360 Below this we see 23:11.840 --> 23:12.370 the musket, 23:12.370 --> 23:15.190 irish mucosa and the 23:15.190 --> 23:17.660 underlying sub mucosa. 23:20.340 --> 23:21.400 The muscular s, 23:21.400 --> 23:23.770 external is cut 23:24.430 --> 23:25.770 in an oblique section, 23:29.640 --> 23:30.960 but in this area 23:32.640 --> 23:35.270 one can see nerve fibers and cells 23:36.040 --> 23:38.050 of the our box plexus, 23:46.340 --> 23:49.230 again noting the nerve fibers 23:49.230 --> 23:51.680 and the bluish staining ganglion 23:51.680 --> 23:52.360 cells. 23:53.240 --> 23:53.450 Mhm. 23:59.420 --> 24:00.560 Now in review 24:03.240 --> 24:05.570 there are two general features which serve to 24:05.570 --> 24:08.160 distinguish the polaris from the funders 24:08.160 --> 24:09.560 portion of the stomach, 24:10.440 --> 24:13.160 first very deep 24:14.940 --> 24:16.670 pit in the polaris 24:17.140 --> 24:19.790 compares with a very shallow pit in the 24:19.790 --> 24:20.390 fungus. 24:21.340 --> 24:22.230 Secondly, 24:22.380 --> 24:24.780 the homogeneous cell types 24:24.790 --> 24:27.390 present within the polaris 24:27.400 --> 24:30.030 contrast with the heterogeneous cells 24:30.390 --> 24:33.160 lining the funding glands. 24:38.140 --> 24:40.570 The next slide will show the first 24:40.580 --> 24:43.350 portion of the small intestine called the 24:43.350 --> 24:43.960 duodenum. 24:46.840 --> 24:49.360 We're looking at a macroscopic view 24:50.300 --> 24:52.960 and beginning on the Luminal side, 24:53.740 --> 24:56.580 one can see first the presence of 24:56.580 --> 24:59.040 Valli or 24:59.040 --> 25:00.960 folds of the lamb inappropriate. 25:02.940 --> 25:05.360 These light stained patches 25:10.040 --> 25:11.770 within the sub mucosa, 25:13.340 --> 25:15.780 our glands and to the 25:15.780 --> 25:18.170 outside we see a thick, 25:18.540 --> 25:20.270 muscular as external. 25:24.740 --> 25:26.200 On our scan objective, 25:26.210 --> 25:29.060 we can see the characteristic Valli 25:32.240 --> 25:34.160 or folds of lamb inappropriate. 25:34.840 --> 25:37.470 With some of the valley cut in cross 25:37.470 --> 25:37.960 section. 25:40.040 --> 25:42.360 Note the presence of the 25:42.610 --> 25:43.930 mucosal glands 25:47.340 --> 25:49.560 and a rather conspicuous mucosa 25:50.940 --> 25:52.170 In the 70 Koza, 25:54.240 --> 25:56.160 no the presence of the light staining 25:58.140 --> 25:59.620 mucous producing glands, 25:59.630 --> 26:02.170 which are termed Brunner's glands. 26:05.840 --> 26:07.850 Again in the 26:08.740 --> 26:10.650 muscular wrist X. 26:10.650 --> 26:11.170 Turn up, 26:12.240 --> 26:14.850 we can see the inner circular 26:16.440 --> 26:19.110 and the outer longitude and the layers. 26:22.240 --> 26:25.060 Note the presence of several lymphatic 26:25.940 --> 26:28.360 Nigel's which can be 26:28.360 --> 26:31.010 present either in the mucosa 26:31.130 --> 26:32.860 or the sub mucosa. 26:37.140 --> 26:40.120 The amount of lymphatic tissue present within the connective 26:40.130 --> 26:43.120 tissue tends 26:43.120 --> 26:45.950 to increase as one moves down the gi 26:45.960 --> 26:46.560 tract. 26:48.240 --> 26:49.800 Changing to our 10 X. 26:49.800 --> 26:50.550 Objective 26:56.640 --> 26:59.270 note that as the Valli 27:00.440 --> 27:03.090 project above the surface there are 27:03.090 --> 27:05.260 small glandular 27:05.260 --> 27:06.500 imaginations 27:09.240 --> 27:11.400 which project into the lamb 27:11.400 --> 27:12.270 inappropriate. 27:15.940 --> 27:17.910 And these mucosal glands 27:19.740 --> 27:22.420 are termed the crips of liberty. 27:30.340 --> 27:32.770 Changing now to our high power objective. 27:38.740 --> 27:39.850 As we began 27:41.640 --> 27:43.960 to examine the surface 27:44.290 --> 27:45.170 epithelium, 27:48.240 --> 27:50.960 we see the presence of first goblet cells 27:53.200 --> 27:56.090 and these are not present in the stomach and are unique 27:56.170 --> 27:58.670 to the small and large intestine. 28:00.540 --> 28:02.550 Note the presence of the brush border 28:05.940 --> 28:08.160 on the service of the epithelial cells, 28:10.040 --> 28:12.560 the lamb inappropriate within the 28:13.340 --> 28:15.490 Valli contained in this case 28:15.910 --> 28:18.690 several plasma cells and other 28:18.690 --> 28:19.850 lymphoid cells 28:22.640 --> 28:23.860 within the core. 28:25.140 --> 28:27.420 one can see very small emphatic 28:27.430 --> 28:28.260 channels 28:31.840 --> 28:34.060 which are termed lacked eels. 28:39.440 --> 28:41.760 To review this section can be 28:41.760 --> 28:44.220 identified as small intestine because of the 28:44.220 --> 28:45.670 presence of Valli 28:48.640 --> 28:50.460 and goblet cells. 28:53.520 --> 28:55.360 To distinguish the duodenum 28:56.440 --> 28:59.160 from the other portions of the small 28:59.160 --> 29:00.060 intestine. 29:00.640 --> 29:03.020 You must identify the 29:03.030 --> 29:05.550 sub mucosal Brunner's 29:05.550 --> 29:08.260 glands which are not present 29:08.840 --> 29:11.360 in any other part of the gi tract. 29:14.340 --> 29:17.340 Let's now examine the next section of the small intestine, 29:17.430 --> 29:18.170 the Juno, 29:19.940 --> 29:22.530 this is on low power with an asian 29:22.540 --> 29:23.560 e stain. 29:24.340 --> 29:26.950 We again see both Valli 29:29.340 --> 29:31.350 and the presence of individual 29:31.840 --> 29:32.950 goblet cells 29:38.640 --> 29:41.160 to all characteristic of the small intestine, 29:42.540 --> 29:44.160 changing to our high power 29:49.440 --> 29:52.060 as we move deeper 29:55.020 --> 29:57.800 into the glandular portion of the crips of labor 29:57.800 --> 29:58.270 coun 30:02.140 --> 30:04.050 we see at the extreme 30:04.540 --> 30:06.270 basil portion 30:08.040 --> 30:09.060 of the land, 30:09.240 --> 30:11.850 the presence of reddish cells. 30:12.940 --> 30:14.910 These cells are termed pan. 30:14.910 --> 30:15.760 It sells 30:19.140 --> 30:21.710 the cells such as the Ar Gentlemen 30:21.710 --> 30:24.290 cells are also 30:24.290 --> 30:27.140 present but will not show with a 30:27.140 --> 30:29.840 standard Hema toxin and es and 30:29.840 --> 30:30.360 stain. 30:40.940 --> 30:43.660 Now in review we 30:43.660 --> 30:45.170 see the Valli. 30:48.640 --> 30:51.150 It's a characteristic of the small 30:51.150 --> 30:51.760 intestine. 30:52.540 --> 30:55.450 We do not see sub mucosal 30:56.140 --> 30:57.210 Brunner's glands. 30:58.340 --> 31:01.050 This fact will serve to distinguish the june um 31:01.270 --> 31:02.860 from the duodenum. 31:04.140 --> 31:06.900 Although the number and the shape 31:07.130 --> 31:07.880 of the village, 31:07.880 --> 31:10.760 I will change gradually from the jejune 31:10.760 --> 31:11.770 um to the ilium. 31:12.540 --> 31:15.320 You will not be required to distinguish between the 31:15.320 --> 31:17.160 june um and the ilium. 31:19.640 --> 31:22.570 We will now examine the structure of the colon 31:22.580 --> 31:23.770 or large intestine. 31:26.140 --> 31:28.130 On the microscopic view, 31:28.140 --> 31:30.910 we see the epithelial surface 31:34.840 --> 31:37.270 and the dark stained area 31:38.140 --> 31:40.660 which contains the sub mucosa 31:40.660 --> 31:42.960 and the muscular as external. 31:44.540 --> 31:47.150 Notice that the colon does not contain 31:47.160 --> 31:49.760 ville I as the small intestine does 31:50.840 --> 31:52.670 but does contain 31:54.440 --> 31:56.270 sub mucosal folds. 32:01.140 --> 32:02.440 On high power. 32:02.640 --> 32:04.670 We see first the surface 32:05.640 --> 32:08.160 epithelial cells and begin to then pick up 32:08.840 --> 32:11.770 presence of goblet cells. 32:12.140 --> 32:13.360 These are indicated here 32:17.940 --> 32:20.600 this combination of godless cells but 32:20.600 --> 32:23.550 novell I tells you it is the colon. 32:25.240 --> 32:28.180 Below this we see the 32:28.390 --> 32:30.460 muscular as mucosa 32:31.810 --> 32:33.660 and a relatively thin 32:34.940 --> 32:35.860 sub mucosa. 32:36.740 --> 32:36.950 Yes, 32:44.340 --> 32:47.060 you may see frequently within the 32:47.540 --> 32:49.590 mucosa and the sub mucosa, 32:49.600 --> 32:50.960 lymphatic modules. 32:52.340 --> 32:55.200 Externally we see 32:55.200 --> 32:57.160 the muscular is external 32:58.640 --> 33:01.060 with a characteristic inner circular 33:02.640 --> 33:04.860 and outer longitudinal 33:05.340 --> 33:06.270 arrangement. 33:09.040 --> 33:11.950 Note the presence of both 33:11.950 --> 33:14.480 cells and fibers of our box 33:14.620 --> 33:15.360 plexus. 33:22.340 --> 33:24.860 Changing back to our scan objective 33:28.940 --> 33:29.560 note 33:31.740 --> 33:34.360 that the outer circular muscle 33:35.240 --> 33:37.950 is thickened into bands 33:38.840 --> 33:41.270 that are known as Tenia coli. 33:45.140 --> 33:48.050 Will now examine a cross section of the appendix 33:51.440 --> 33:54.290 beginning on the Luminal side. 33:56.140 --> 33:56.340 Yeah, 33:57.140 --> 33:59.450 we see first goblet cells 34:02.940 --> 34:03.960 and no Valli. 34:05.240 --> 34:08.170 This finding is compatible with the distinguishing 34:08.170 --> 34:09.760 characteristics in the colon. 34:11.440 --> 34:13.860 Within the lamb inappropriate. 34:15.540 --> 34:18.260 We see a very heavy invasion of lymphocytic 34:18.260 --> 34:20.410 cells and a 34:20.410 --> 34:22.600 conspicuous muscular as 34:23.040 --> 34:23.760 mucosa. 34:25.040 --> 34:25.250 Okay, 34:25.940 --> 34:27.970 and the sub mucosa 34:29.840 --> 34:32.380 we again see several modular masses 34:34.140 --> 34:35.670 of lymphatic tissue. 34:36.140 --> 34:37.970 And on the outside 34:40.040 --> 34:42.580 we see a rather 34:42.580 --> 34:44.870 than muscular eras 34:45.150 --> 34:45.760 external. 34:46.540 --> 34:47.150 Again, 34:47.150 --> 34:49.850 we have an inner circular 34:50.340 --> 34:52.560 and an outer longitudinal 34:53.040 --> 34:55.350 arrangement of smooth muscle cells. 34:56.740 --> 34:59.370 So in review the 34:59.370 --> 35:01.590 appendix has the structure 35:02.240 --> 35:03.170 of the colon, 35:04.240 --> 35:06.350 but it's always heavily 35:06.350 --> 35:08.810 infiltrated with 35:08.810 --> 35:10.240 lymphoid cells. 35:10.490 --> 35:11.170 Therefore, 35:11.810 --> 35:14.540 the appendix can be considered as a 35:14.540 --> 35:15.170 council. 35:17.340 --> 35:18.260 This mask 35:20.340 --> 35:22.790 within the lumen is partially 35:22.800 --> 35:24.470 digested material. 35:27.040 --> 35:29.860 On the last slide we'll examine the 35:29.860 --> 35:31.560 rectal anal canal. 35:32.640 --> 35:32.840 Yeah, 35:33.840 --> 35:36.530 in the rectum we continue to have the 35:36.530 --> 35:37.390 glands, 35:37.940 --> 35:38.920 our cribs, 35:39.640 --> 35:42.280 nobody broken with no 35:42.280 --> 35:45.010 Valli and a 35:45.010 --> 35:47.170 large number from God, 35:47.170 --> 35:47.970 but cells, 35:51.340 --> 35:53.490 this finding is consistent with the 35:53.490 --> 35:55.170 morphology of the colon. 35:56.040 --> 35:56.700 However, 35:56.700 --> 35:59.680 there are no 10ia coli in 35:59.680 --> 36:00.240 the rectum 36:03.630 --> 36:06.350 due to the oblique section 36:07.030 --> 36:08.050 of this slide, 36:09.030 --> 36:11.930 the outer longitudinal and 36:11.930 --> 36:14.670 the inner circular layers of the muscular s. 36:14.670 --> 36:16.850 External do not show. 36:18.730 --> 36:19.540 As we 36:20.830 --> 36:21.750 move 36:22.930 --> 36:25.300 toward the anal canal. 36:30.730 --> 36:33.500 We see that in the anal canal there is 36:33.640 --> 36:36.190 a transition from a simple kilometer 36:36.200 --> 36:39.080 epithelium to a non 36:39.080 --> 36:39.620 carotene. 36:39.620 --> 36:40.250 Ized, 36:41.420 --> 36:44.250 stratified squamous epithelium. 36:46.430 --> 36:49.300 There is not a sharply 36:49.310 --> 36:52.250 defined muscular as mucosa, 36:52.730 --> 36:54.950 and therefore the separation 36:55.730 --> 36:58.560 between the mucosa and the 36:58.560 --> 37:00.960 sub mucosa is not clear 37:02.330 --> 37:04.950 due to the heavy concentration of the lymphatic 37:04.960 --> 37:07.460 tissue within the mucosal 37:07.830 --> 37:09.500 and sub mucosal areas. 37:12.930 --> 37:15.650 These features will help to 37:15.650 --> 37:18.440 differentiate this part of the anal canal 37:18.450 --> 37:19.840 from the esophagus. 37:22.330 --> 37:22.530 Now, 37:22.530 --> 37:24.850 as we move down 37:26.530 --> 37:27.660 the anal canal, 37:28.730 --> 37:30.160 there will be a transition 37:31.730 --> 37:33.850 from the non character in Ized 37:35.130 --> 37:37.810 stratified squamous epithelium to the carotene. 37:37.810 --> 37:39.660 Ized empathy Veum 37:40.730 --> 37:42.950 as seen in these areas, 37:48.030 --> 37:50.810 and this will become continuous then with the 37:50.810 --> 37:52.510 skin thin skin. 37:52.510 --> 37:53.750 At this point 37:55.830 --> 37:58.060 this area contains 37:58.630 --> 37:59.550 para follicles 38:01.320 --> 38:03.680 and sebaceous glands, 38:05.320 --> 38:07.750 all of which are consistent with the 38:07.750 --> 38:10.240 structure of thin skin. 38:11.920 --> 38:14.830 This completes the tape on the GI tract.