1 00:00:00,820 --> 00:00:05,700 Okay, so what have we studied so far? 2 00:00:05,799 --> 00:00:07,480 Let's give a quick review, okay? 3 00:00:07,480 --> 00:00:12,460 We have studied how are the male and female reproductive systems. 4 00:00:12,859 --> 00:00:19,179 Then we have studied how to produce ova and spermatozoa, okay? 5 00:00:19,339 --> 00:00:20,300 The sexual cells. 6 00:00:20,879 --> 00:00:26,500 And then we have studied which layers they have and what is their structure, okay? 7 00:00:26,500 --> 00:00:32,520 And now what I'm going to explain you is what happens if actually there is fertilization, okay? 8 00:00:32,520 --> 00:00:37,000 So how is the new human going to be formed, okay? 9 00:00:37,079 --> 00:00:38,939 And which things are going to happen, right? 10 00:00:39,859 --> 00:00:40,520 Okay, good. 11 00:00:41,020 --> 00:00:42,520 So we have here two situations. 12 00:00:43,460 --> 00:00:47,060 First situation, the ovary, this is the ovary, okay? 13 00:00:47,219 --> 00:00:49,560 The ovary produces one ovum. 14 00:00:49,820 --> 00:00:56,479 We said we produce one every month, okay, around one month, and only from one of the ovaries, okay? 15 00:00:56,500 --> 00:01:05,560 One month from the one on one side, the one on the right, and the other month, the next month, from the other ovary, the one on the left. 16 00:01:07,180 --> 00:01:12,719 Fine, so this is the ovum that has just been released to the fallopian tube. 17 00:01:13,540 --> 00:01:16,799 And when the ovum is here, two things can happen. 18 00:01:17,319 --> 00:01:19,739 First of all, there is no fertilization. 19 00:01:19,739 --> 00:01:22,599 If there are no spermatozoa around 20 00:01:22,599 --> 00:01:24,400 There are no spermatozoa around 21 00:01:24,400 --> 00:01:26,560 Or there are some 22 00:01:26,560 --> 00:01:28,879 But there is no fertilization anyway 23 00:01:28,879 --> 00:01:30,719 Because it doesn't work for a reason 24 00:01:30,719 --> 00:01:31,239 Okay 25 00:01:31,239 --> 00:01:34,540 Then the ovum, what is it going to do? 26 00:01:34,700 --> 00:01:36,900 It's going to travel through the fallopian tube 27 00:01:36,900 --> 00:01:38,400 And it will leave the body 28 00:01:38,400 --> 00:01:39,340 Through the vagina 29 00:01:39,340 --> 00:01:41,519 But we won't feel anything 30 00:01:41,519 --> 00:01:43,920 Because the ovum is just one cell 31 00:01:43,920 --> 00:01:46,200 So every month 32 00:01:46,200 --> 00:01:47,659 When you don't get pregnant 33 00:01:47,659 --> 00:01:49,120 You lose the ovum 34 00:01:49,120 --> 00:01:55,040 but you don't realize because it's just one cell it's very tiny okay it's absolutely tiny right 35 00:01:55,680 --> 00:01:58,000 okay so this is what usually happens right 36 00:02:13,280 --> 00:02:18,560 okay so this is what what most of the times happen right the 37 00:02:19,120 --> 00:02:25,120 produced it is produced it travels through the body and it gets out and nothing happens there 38 00:02:25,120 --> 00:02:32,319 right but what happens if that time there were spermatozoa around the spermatozoa had to travel 39 00:02:32,319 --> 00:02:38,000 right through the vagina then it goes through the uterus through the fallopian tube and they swim 40 00:02:38,000 --> 00:02:44,080 in their own liquid and in your internal liquids okay they are swimming and they do it right many 41 00:02:44,080 --> 00:02:51,680 of them reach the own womb this happens okay fine this is how we all have survived as a species and 42 00:02:51,680 --> 00:02:55,919 we are doing it quite well because there are many humans in the planet okay yes question 43 00:03:00,969 --> 00:03:02,569 is 44 00:03:15,770 --> 00:03:18,030 I'm going to explain it anyway for everyone who comes to class, okay? 45 00:03:18,069 --> 00:03:19,310 No, no, it's a concept of the objective. 46 00:03:19,509 --> 00:03:22,150 We'll talk about the anti-conceptive aspects the next day, okay? 47 00:03:22,229 --> 00:03:23,909 Because if not, I don't have time to talk about it, okay? 48 00:03:23,990 --> 00:03:25,650 What are we going to do? 49 00:03:25,830 --> 00:03:28,330 Another question that I can't answer now because I'm trying to explain. 50 00:03:28,569 --> 00:03:30,770 Can we answer these questions? 51 00:03:31,550 --> 00:03:35,469 The one about what we're going to do later and the other one, I'll answer it when I can explain it, okay? 52 00:03:35,669 --> 00:03:37,210 Yes, if not, you don't give us the explanation today. 53 00:03:37,270 --> 00:03:38,889 You already know that we don't have more time, okay? 54 00:03:40,389 --> 00:03:41,229 Come on, nice. 55 00:03:41,229 --> 00:04:00,789 Okay, so here we have the ovum and today the spermatozoids are there. Okay, finally, fantastic. Okay, so what do they do? They surround the ovum and one of them is going to release the enzymes from something it had in the head. 56 00:04:00,789 --> 00:04:07,729 Can you tell me which structure the spermatozoid has in the head for that? 57 00:04:08,289 --> 00:04:12,949 That I said a couple of classes ago, or in the last class even. 58 00:04:12,969 --> 00:04:13,550 The acrosome. 59 00:04:13,650 --> 00:04:15,469 The acrosome, yes, very good, okay. 60 00:04:16,290 --> 00:04:20,610 In the head of the spermatozoid, there is a big vesicle with enzymes, 61 00:04:20,930 --> 00:04:24,529 and those enzymes are going to leave the spermatozoid, okay, 62 00:04:24,730 --> 00:04:26,290 and what are they going to do? 63 00:04:26,290 --> 00:04:30,269 They are going to make like a little hole, como un agujerito, 64 00:04:30,790 --> 00:04:32,689 in the ovum, okay? 65 00:04:32,889 --> 00:04:36,649 They are going to digest and cut the membranes of the ovum. 66 00:04:37,490 --> 00:04:40,850 And what is the intention of the spermatozoid? 67 00:04:41,310 --> 00:04:44,029 Its intention is to put its nucleus, 68 00:04:44,329 --> 00:04:46,310 el núcleo que tiene el material genético, 69 00:04:46,449 --> 00:04:49,649 with the genetic material, inside the ovum, okay? 70 00:04:50,750 --> 00:04:55,170 So, the male cell, 71 00:04:55,649 --> 00:04:57,329 a ver, que quería ampliar esto un poco más, 72 00:04:57,329 --> 00:05:07,329 the idea is that the spermatozoid is not going to enter full into the womb no no no just the nucleus 73 00:05:07,329 --> 00:05:12,990 centers okay solo entra el nucleo vale el nucleo de la célula el resto del espermatozoide no entra 74 00:05:12,990 --> 00:05:19,449 se queda fuera vale así pero cuando se entra de todos los que van todos uno y porque solo uno 75 00:05:19,449 --> 00:05:25,009 porque no puedes tener tanto material genético solo puedes tener el tuyo y el de un macho o sea 76 00:05:25,009 --> 00:05:27,009 A genetic material of a cell of a male. 77 00:05:27,009 --> 00:05:29,009 I don't know if that's true. 78 00:05:29,009 --> 00:05:31,009 Okay, so now we are going to explain that. 79 00:05:31,009 --> 00:05:39,009 Okay, so when one of them makes it, when one of them puts its nucleus inside the ovum... 80 00:05:39,009 --> 00:05:41,009 Not exactly. 81 00:05:41,009 --> 00:05:43,009 As you are not exactly the same as... 82 00:05:43,009 --> 00:05:45,009 Do you have siblings, brothers or sisters? 83 00:05:45,009 --> 00:05:47,009 Yes. Are you exactly the same? 84 00:05:47,009 --> 00:05:54,009 No. This is because the genetic material in the ovum and spermatozoid, they have a mix of genes. 85 00:05:54,009 --> 00:06:00,009 No, I mean, when all the neurons go to the ovum, they are all the same. 86 00:06:00,009 --> 00:06:07,009 No, they are not all the same. There are some small genetic changes. We will study that next year, in the fourth year. 87 00:06:07,009 --> 00:06:15,009 The one that arrives first and the one that first manages to put its nucleus in the ovum. 88 00:06:15,009 --> 00:06:18,009 There is one that will arrive first and will be able to put its nucleus. 89 00:06:18,009 --> 00:06:22,470 Okay, so when that one makes it, the one that makes it before, 90 00:06:23,370 --> 00:06:25,110 just the nucleus of one. 91 00:06:26,589 --> 00:06:27,269 But they haven't entered. 92 00:06:27,750 --> 00:06:29,329 Only one will enter, okay? 93 00:06:30,029 --> 00:06:31,050 They haven't entered, only one will enter. 94 00:06:31,350 --> 00:06:35,389 Okay, so when the nucleus of one of them is inside, 95 00:06:35,990 --> 00:06:37,870 then what does the ovum do? 96 00:06:38,029 --> 00:06:39,629 It creates a new membrane. 97 00:06:40,550 --> 00:06:47,370 It's called the fertilizing membrane. 98 00:06:47,370 --> 00:06:49,949 the fertilizing membrane 99 00:06:49,949 --> 00:06:50,649 you have it here 100 00:06:50,649 --> 00:06:53,829 so the ovum is going to create an extra layer 101 00:06:53,829 --> 00:06:56,170 and then this layer is there 102 00:06:56,170 --> 00:06:57,209 to prevent 103 00:06:57,209 --> 00:07:00,050 other spermatozoa to put their 104 00:07:00,050 --> 00:07:00,709 nucleus there 105 00:07:00,709 --> 00:07:02,550 I repeat it in Spanish 106 00:07:02,550 --> 00:07:05,850 ¿Para qué crea el óvulo una nueva membrana? 107 00:07:06,350 --> 00:07:07,910 La membrana que se llama de fecundación 108 00:07:07,910 --> 00:07:10,069 en español o fertilization en inglés 109 00:07:10,069 --> 00:07:11,649 ¿Para evitar qué? 110 00:07:12,949 --> 00:07:13,810 Que haya otra vez 111 00:07:13,810 --> 00:07:15,509 ¿Que venga quién? 112 00:07:15,629 --> 00:07:16,189 ¿Que entre quién? 113 00:07:16,189 --> 00:07:17,470 The spermatozoa with the nucleus. 114 00:07:17,569 --> 00:07:19,009 That another spermatozoid enters the nucleus. 115 00:07:19,110 --> 00:07:19,790 Only one can enter. 116 00:07:21,170 --> 00:07:21,689 Why? 117 00:07:22,009 --> 00:07:22,550 Well, you'll see. 118 00:07:22,709 --> 00:07:27,689 Because the chromosomes that the ovum has are a series of chromosomes 119 00:07:27,689 --> 00:07:32,029 and it can only admit one chromosome of the spermatozoid. 120 00:07:32,250 --> 00:07:35,209 And if another one comes, it would create an impossible human. 121 00:07:35,490 --> 00:07:36,689 It has three chromosomes. 122 00:07:36,910 --> 00:07:37,449 That doesn't exist. 123 00:07:37,930 --> 00:07:38,089 Okay? 124 00:07:38,370 --> 00:07:39,009 That's impossible. 125 00:07:39,230 --> 00:07:39,990 That doesn't work. 126 00:07:40,110 --> 00:07:40,949 And sometimes two can happen. 127 00:07:41,350 --> 00:07:41,670 No, no. 128 00:07:41,970 --> 00:07:42,389 No, no. 129 00:07:42,529 --> 00:07:43,110 It never happens. 130 00:07:43,329 --> 00:07:43,629 No, no. 131 00:07:43,629 --> 00:07:44,170 No, no, never. 132 00:07:44,509 --> 00:07:44,709 Okay? 133 00:07:44,709 --> 00:07:54,709 If we put that it happened in the hypothetical case, that pregnancy would never continue, because there is no human with three chromosomes, we only have two. 134 00:07:54,709 --> 00:07:58,709 We study this in more detail next year, in the fourth. 135 00:07:58,709 --> 00:08:03,709 But that is another case, twins and twins. 136 00:08:03,709 --> 00:08:04,709 No, no, no. 137 00:08:04,709 --> 00:08:05,709 Siameses. 138 00:08:05,709 --> 00:08:08,709 Siameses, that is a mistake during development. 139 00:08:08,709 --> 00:08:12,709 That is a mistake in the development of the babies, very later. 140 00:08:12,709 --> 00:08:25,709 That is to say that they are twins that have had a very big role in development, but they are already like some cases, we will talk about those cases later, we are going to count as usual and then the cases, yes? 141 00:08:25,709 --> 00:08:40,710 Ok, fine, so here we tell do we get when we mix the genetic material of the ovum and the spermatozoid, we have them together now, how is that cell called, the new cell? 142 00:08:40,710 --> 00:08:51,909 Tenemos una nueva célula con el material genético del macho y de la hembra, junta, esta célula, que la conocéis, el cigoto, the zygote, ok? The zygote. 143 00:08:52,070 --> 00:09:05,970 This cell has the genetic material from the male and from the female, and this cell is the one that is going to make a new human, ok? So this cell is responsible of making the new human, ok? 144 00:09:05,970 --> 00:09:12,529 so this cell now is going to start dividing and it's going to form what it's called an embryo 145 00:09:12,529 --> 00:09:17,970 first and an embryo is it's just a group of cells that are dividing very quickly 146 00:09:17,970 --> 00:09:24,889 and they start to differentiate which means they start to form the different tissues okay the 147 00:09:24,889 --> 00:09:32,809 nervous tissue the muscular tissue but in the beginning just in the first six to ten days 148 00:09:32,809 --> 00:09:34,750 after fertilization 149 00:09:34,750 --> 00:09:36,490 then 150 00:09:36,490 --> 00:09:38,389 this embryo is going to travel 151 00:09:38,389 --> 00:09:39,750 towards the uterus 152 00:09:39,750 --> 00:09:42,830 and when it reaches this position 153 00:09:42,830 --> 00:09:43,850 when it's here 154 00:09:43,850 --> 00:09:46,789 when it reaches 155 00:09:46,789 --> 00:09:48,850 this position, it's like 156 00:09:48,850 --> 00:09:50,629 as I said, let's say a week 157 00:09:50,629 --> 00:09:52,429 a week or so after 158 00:09:52,429 --> 00:09:54,710 fertilization. So let's imagine 159 00:09:54,710 --> 00:09:56,929 in an ideal situation that the woman 160 00:09:56,929 --> 00:09:57,909 is ovulating 161 00:09:57,909 --> 00:10:00,750 on day 14, right? 162 00:10:01,210 --> 00:10:01,809 Then 163 00:10:01,809 --> 00:10:05,009 there is fertilization 164 00:10:05,009 --> 00:10:07,009 so in the next week 165 00:10:07,009 --> 00:10:09,250 the embryo is going to travel 166 00:10:09,250 --> 00:10:10,509 through the fallopian tube 167 00:10:10,509 --> 00:10:12,370 until it reaches the endometrium 168 00:10:12,370 --> 00:10:14,889 and the endometrium is ready at that moment 169 00:10:14,889 --> 00:10:17,049 because we said we were building 170 00:10:17,049 --> 00:10:18,950 a nest for it, do you remember? 171 00:10:20,250 --> 00:10:21,129 Progesterone was 172 00:10:21,129 --> 00:10:23,009 high and we were building 173 00:10:23,009 --> 00:10:24,950 a very good nest 174 00:10:24,950 --> 00:10:25,909 for the embryo 175 00:10:25,909 --> 00:10:28,230 so in the third week 176 00:10:28,230 --> 00:10:30,269 if the embryo arrives 177 00:10:30,269 --> 00:10:33,210 then it's going to be received 178 00:10:33,210 --> 00:10:35,169 by a great nest 179 00:10:35,169 --> 00:10:37,289 which is the endometrium newly formed 180 00:10:37,289 --> 00:10:39,190 el endometrio recién formado 181 00:10:39,190 --> 00:10:39,909 que habíamos hecho 182 00:10:39,909 --> 00:10:42,470 lo hemos explicado antes con el ciclo menstrual 183 00:10:42,470 --> 00:10:44,929 hemos hecho un endometrio nuevo, hacemos uno cada mes 184 00:10:44,929 --> 00:10:46,769 en la segunda parte del ciclo 185 00:10:46,769 --> 00:10:48,250 si ha habido embarazo 186 00:10:48,250 --> 00:10:51,549 justamente el embrión baja y se encuentra con un endometrio 187 00:10:51,549 --> 00:10:52,929 estupendo y recién formado 188 00:10:52,929 --> 00:10:54,769 ¿vale? porque el objetivo 189 00:10:54,769 --> 00:10:57,230 es que se forme, que se quede allí 190 00:10:57,230 --> 00:11:19,129 Okay, so if the embryo reaches the endometrium and it stays there, it stays there and staying there is called it implants, se implanta, ¿vale? Se implanta en el endometrio, se dice en español y en inglés igual, ¿okay? It implants in the endometrium and if it manages to stay there, then the pregnancy will continue. 191 00:11:19,129 --> 00:11:41,269 And what happens then? I'm going back to my skin, okay? Just for a moment. Okay. So, ovulation, right? If there is fertilization, a few days later, a few days later, this ovum fertilized is going to find an endometrium, which is great, right? Great to receive it. 192 00:11:41,269 --> 00:12:01,889 And then if there is fertilization at this stage, then the embryo produces a different hormone that you don't have in your books and it has a difficult name, which is called casually, quiero decir, se llama de forma coloquial la hormona del embarazo, se le llama, ¿vale? La hormona del embarazo. 193 00:12:01,889 --> 00:12:05,889 If there has been an implantation of the embryo, the embryo produces a new hormone. 194 00:12:05,889 --> 00:12:07,889 And what do you think that new hormone will do? 195 00:12:07,889 --> 00:12:11,889 Will it allow menstruation to come here on the 28th? 196 00:12:11,889 --> 00:12:14,889 No, then we destroy the embryo. 197 00:12:14,889 --> 00:12:21,889 If the rule comes, then the embryo leaves because all the endometrium is broken, we have said. 198 00:12:21,889 --> 00:12:26,889 So what does the embryo do? It produces a hormone called the pregnancy hormone. 199 00:12:26,889 --> 00:12:29,889 You don't have it out there either, but you know it. 200 00:12:29,889 --> 00:12:34,269 That pregnancy hormone is the one that detects a pregnancy test, okay? 201 00:12:35,110 --> 00:12:40,230 If you take a pregnancy test, because it's been, I don't know, 28, 32 days, 202 00:12:41,230 --> 00:12:44,570 and normally you should have come to the rule, and you've had sexual relations, 203 00:12:44,830 --> 00:12:48,070 and you're worried, because let's see if you've had it and you're pregnant, okay? 204 00:12:48,250 --> 00:12:50,669 And you decide to take your pregnancy test, okay? 205 00:12:51,149 --> 00:12:53,830 What do you do? You urinate in the pregnancy test, okay? 206 00:12:53,909 --> 00:12:55,269 It's called PIS, urine, okay? 207 00:12:56,009 --> 00:12:58,169 The pregnancy test is what detects the urine. 208 00:12:58,169 --> 00:13:21,620 If your body is producing pregnancy hormone. Who has produced that hormone? If it is the embryo, okay? The embryo that is here. Let's see, okay? If the embryo is here and produces pregnancy hormone, that hormone, like all hormones, goes to the blood. And remember that the blood was filtered in the kidney and goes to the urine, okay? 209 00:13:21,620 --> 00:13:27,139 so why is that hormone measured in the urine because that is where it has to be measured in the urine 210 00:13:27,139 --> 00:13:31,940 because everything that is in the blood at the end is filtered and it ends in the urine and remembering 211 00:13:31,940 --> 00:13:37,879 yes then if I have a pregnancy test and there is pregnancy then it comes out positive because there is a 212 00:13:37,879 --> 00:13:43,379 pregnancy hormone and if it comes out negative because if maybe it is that the test is very soon and 213 00:13:43,379 --> 00:13:47,539 the levels are still very low or maybe it is that I am not pregnant and I just have to wait a little 214 00:13:47,539 --> 00:13:50,539 One of the two things has to happen, right? 215 00:13:50,539 --> 00:13:55,539 Either she ends up giving me the rule or she ends up giving the pregnancy test positive, right? 216 00:13:55,539 --> 00:13:58,539 One of the two things has to happen, right? 217 00:13:58,539 --> 00:14:02,539 Questions? No? Not right now? 218 00:14:02,539 --> 00:14:09,539 Okay, so we are going to continue thinking that today we do have a pregnancy, okay? 219 00:14:09,539 --> 00:14:12,539 We are pregnant. So what happens now? 220 00:14:12,539 --> 00:14:14,539 That's what we are going to do, okay? 221 00:14:14,539 --> 00:14:17,019 Okay, let's move into the next page.