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Embryology, Anatomy, and Physiology of the Male Reproductive System
Published in Karl H. Pang, Nadir I. Osman, James W.F. Catto, Christopher R. Chapple, Basic Urological Sciences, 2021
Proliferative phaseSpermatogonial stem cells (diploid, 2n) located near the basement membrane divide by mitosis to form type A and type B spermatogonia.Type A replenish the spermatogonial stem cells.Type B spermatogonia form primary spermatocytes.
Knowledge Area 11: Subfertility
Published in Rekha Wuntakal, Ziena Abdullah, Tony Hollingworth, Get Through MRCOG Part 1, 2020
Rekha Wuntakal, Ziena Abdullah, Tony Hollingworth
The time required for a spermatogonium to develop into a mature spermatozoon is around 64 days. Spermatozoa enter the lumen of seminiferous tubules once fully formed. Thereafter, they are pushed towards the epididymis and obtain full motility in the epididymis.
Effects of Environmental Factors on the Endocrine System
Published in George H. Gass, Harold M. Kaplan, Handbook of Endocrinology, 2020
In contrast to oogenesis, the entire process of spermatogenesis occurs in the adult testis. Spermatogonia lying along the basement membrane of the seminiferous tubule mitose to maintain the stem cell population. Whereas type A spermatogonia continue to divide mitotically, type B spermatogonia derived from some of their daughter cells, intermediate spermatogonia, further divide into primary spermatocytes. Each primary spermatocyte undergoes meiosis and differentiates into a sperm. Because it takes about 64 days for a spermatogonium to form a matured sperm, spermatogenesis can easily be disrupted at any point by toxins.
A review of protein-protein interaction and signaling pathway of Vimentin in cell regulation, morphology and cell differentiation in normal cells
Published in Journal of Receptors and Signal Transduction, 2022
Danial Hashemi Karoii, Hossein Azizi
Our recent study shows that Vimentin is a critical intermediate filament of testicular germ cells for differentiation and that it is increased throughout the spermatogenesis differentiation phases. The results show that Vimentin is strongly expressed in the core of testicular cords, seminiferous tubule cells, and the differentiated section (Figure 2). This seems to be strongly expressed during differentiation, and its rise appears to be related to differentiation. Future research on the Vimentin expression pattern against infertility and other reproductive problems in males will be beneficial based on the use of SSCs in clinical and therapeutic situations and the impact of Vimentin on the activity of these cells [11,66,67]. Finally, we found the gene expression in spermatogonia stems cells throughout testicular development. We show that this knowledge will be helpful in understanding spermatogonia stem cell formation, cell culture, and infertility disorders.
Premature ovarian insufficiency: an International Menopause Society White Paper
Published in Climacteric, 2020
N. Panay, R. A. Anderson, R. E. Nappi, A. J. Vincent, S. Vujovic, L. Webber, W. Wolfman
One of the key differences between the male and female reproductive systems is that, in the male, gametogenesis continues throughout adult life with little diminution, whereas female reproduction is characterized by its finite duration and indeed the significant reduction in gamete quality in the later reproductive years. The biological basis for this is the presence of spermatogonial stem cells within the testis, which undergo unequal division to form daughter spermatogonia but with retention of the key stem cell characteristics in one product of that division. By contrast, in the female it is understood that all oocytes are formed during fetal life, following a wave of meiosis in the late first and early second trimesters of pregnancy. All oogonia within the ovary thus enter meiosis with subsequent arrest at prophase of meiosis I, with formation at that same time of the pool of primordial follicles, which constitutes the ovarian reserve.
Differentiation of neonate mouse spermatogonial stem cells on three-dimensional agar/polyvinyl alcohol nanofiber scaffold
Published in Systems Biology in Reproductive Medicine, 2020
Marzieh Ziloochi Kashani, Zohreh Bagher, Hamid Reza Asgari, Mohammad Najafi, Morteza Koruji, Fereshteh Mehraein
Since spermatogenesis begins shortly after birth in rodents, the testicular cells of 3–6-day-old mice were used in this research work. During this period, a population of undifferentiated spermatogonial stem cells arises from a subset of gonocytes which are located within the center of seminiferous tubules (Drumond et al. 2011). These undifferentiated cells are called type Asingle spermatogonia and have classically been considered as the SSC population (Ehmcke et al. 2006). Mitotic division of Asingle produces committed progenitor spermatogonia (i.e., Apaired and Aaligned) which, along with Asingle cells, are collectively regarded as undifferentiated A-spermatogonia according to morphological characteristics (Clermont and Bustos-Obregon 1968; Fayomi and Orwig 2018). Further mitotic divisions of undifferentiated A-spermatogonia generate a series of differentiating spermatogonia, including A1, A2, A3, A4, intermediate, and B spermatogonia. Eventually, type B spermatogonia differentiate into primary spermatocytes that will undergo two meiotic divisions to generate round spermatids. Morphological differentiation (spermiogenesis) of these haploid cells leads to the development of mature sperms.