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Spermatogenesis: from Spermatogonium to Spermatid (Nursing)

by Jasmine Clark

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    00:00 Now, let's discuss the specifics of gamete formation in the male reproductive system.

    00:07 This is referred to as spermatogenesis.

    00:10 Spermatogenesis is the production of sperm or spermatozoa, in the seminiferous tubules of the testes.

    00:20 Again, spermatogenesis is going to occur in the seminiferous tubules of the testes.

    00:27 First, you have spermatogenic cells which are going to give rise to sperm.

    00:33 and this is going to happen in three steps.

    00:37 First, we're going to have mitosis of stem cells known as spermatogonia.

    00:44 These are going to form 2 spermatocyte known as primary spermatocyte.

    00:51 Because this is mitosis these two new cells are genetically identical to their spermatogonium and they are diploid.

    01:02 After mitosis of the spermatogonia we have meiosis.

    01:07 In this process, these primary spermatocyte will undergo Meiosis I in order to form secondary spermatocyte and then they will undergo Meiosis II to form spermatids.

    01:23 After this, the spermatids will become sperm cells by way of a process known as spermiogenesis.

    01:34 So let's take a closer look at this process.

    01:38 First, starting with the mitosis of spermatogonia, we're going to form our primary spermatocyte.

    01:46 Spermatogenesis begins at puberty with our spermatogonia.

    01:52 These are stem cells that are located at the epithelial basal lamina portion of the testes in the seminiferous tubules.

    02:02 Each mitotic division of the spermatogonia is going to yield two cells: a Type A daughter cell and a Type B daughter cell.

    02:13 The Type A cells will maintain the germ cell line at the basal lamina and stay at that area.

    02:22 The Type B cells, however, will move toward the lumen and develop into primary spermatocytes.

    02:32 Next, we have meiosis.

    02:35 In this process, these spermatocytes will now be converted to spermatids.

    02:41 In Meiosis I, the primary spermatocyte which is diploid is going to undergo Meiosis I forming 2 secondary spermatocytes that are now haploid.

    02:54 In Meiosis II, the secondary spermatocytes will rapidly undergo Meiosis II to become 2 spermatids that are also haploid.

    03:04 So all together, from the original spermatogonium we end up with 4 spermatids.

    03:14 Spermatids are small, nonmotile cells that are going to be found close to the lumen of the tubule.

    03:24 Now that we have our spermatids, we undergo the third process of spermatogenesis, which is spermiogenesis or the formation of sperm.

    03:35 Spermatids are going to contain the correct haploid chromosome number needed for fertilization, but these are nonmotile.

    03:46 In spermiogenesis, we're going to streamline the process where the spermatid is going to elongate loses excess cytoplasm and form a tail in order to become our spermatozoan or sperm.

    04:02 Now, let's examine this in the context of the testes.

    04:07 Spermatogenesis takes place in the seminiferous tubules of the testes where we have spermatogonia and supporting cells known as sustentocytes or Sertoli cells.

    04:19 Recall that the spermatogonium which are sperm forming stem cells undergo mitosis just beneath the basal lamina, and produce diploid cells.

    04:32 While the Type A cells will remain at the basal lamina, the type B cells will become primary spermatocytes.

    04:41 Also, we have tight junctions between the sustenocytes that are going to prevent leakage of substances from the blood between these cells and block access to these developing sperm.

    04:56 This is what's referred to as the Blood-testis barrier.

    05:00 This is important because it prevents the immune system from attacking the spermatogenic cells.

    05:11 The Type B cells will undergo meiosis I and II.

    05:16 This will then form haploid early spermatids that are way from the basal lamina, and toward the lumen of the seminiferous tubule.

    05:28 The early spermatids will now begin to form what will eventually become our spermatozoa or sperm.

    05:36 This is going to happen through the process of spermiogenesis.


    About the Lecture

    The lecture Spermatogenesis: from Spermatogonium to Spermatid (Nursing) by Jasmine Clark is from the course Male Reproductive System – Physiology (Nursing).


    Included Quiz Questions

    1. Mitosis, meiosis I, meiosis II, and spermiogenesis
    2. Spermiogenesis, meiosis I, meiosis II, and metaphase I
    3. Mitosis, spermiogenesis, metaphase I, and metaphase II
    4. Meiosis I, meiosis II, metaphase I, and metaphase II
    1. Maintain the germ cell line at the basal lamina
    2. Move toward the lumen and develop into primary spermatocytes
    3. Become spermatogonia after meiosis I
    4. Divide only before meiosis II occurs
    1. The primary spermatocyte forms 2 secondary spermatocytes.
    2. The primary spermatocyte becomes 2 separate spermatids.
    3. The primary spermatogonium becomes 2 separate spermatocytes.
    4. The secondary spermatocyte becomes 2 separate spermatids.
    1. Sustenocytes
    2. Spermatocytes
    3. Type A cells
    4. Type B cells
    1. FSH
    2. GnRH
    3. LH
    4. HCG

    Author of lecture Spermatogenesis: from Spermatogonium to Spermatid (Nursing)

     Jasmine Clark

    Jasmine Clark


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