Radiation Damage of the Reproductive Organs
Kedar N. Prasad in Handbook of RADIOBIOLOGY, 2020
The processes of the formation of sperm are referred to as spermatogenesis. The highly proliferating spermatogonia line the seminiferous tubules and give rise to primary and secondary spermatocytes, which then form spermatids. The spermatids do not divide. Each spermatid matures into one spermatozoon. On the criterion of cell death, spermatogonia are most radiosensitive, whereas spermatids and spermatozoa are most radioresistant, but the possibility of genetic damage is high for all cellular elements. The interstitial cells that produce male hormone are also highly radioresistant. Therefore, men exposed at a sterilizing dose (500–600 rads) of radiation retain their fertility and produce seminal and prostatic fluid without sperm for a while. After irradiation, the testis becomes smaller and softer, and may become sterile. However, no change in the beard, voice, or social behavior has been observed.
Anatomy and physiology
Suzanne Everett in Handbook of Contraception and Sexual Health, 2020
Production of sperm, called spermatogenesis, happens in the seminiferous tubules in the testes. The seminiferous tubules are surrounded by a connective tissue which contains Leydig cells (interstitial cells) which are responsible for synthesis and production of male hormones. In the seminiferous there are germ cells and Sertoli cells. Some of the germ cells mature to become primary spermatocytes. The primary spermatocytes undergo meiotic division to become secondary spermatocytes. These then undergo further meiotic division to become spermatids. Spermatids transform into spermatozoa with the support from Sertoli cells which it is attached to; it is thought that Sertoli cells help with nutrition of germ cells. Once the spermatozoa have been produced, they are released from Sertoli cells into the lumen of the seminiferous tubules. It takes 70–100 days for production of mature sperm.
Influence of Environmental Agents on Male Reproductive Failure
Vilma R. Hunt, Kathleen Lucas-Wallace, Jeanne M. Manson in Work and the Health of Women, 2020
Spermatocytes undergo two maturational, meiotic divisions to reduce chromosomal number and produce a cluster of spermatids. As meiosis progresses, primary spermatocytes become larger and migrate from the basement membrane of the Sertoli cell toward the luminal surface projecting into the seminiferous tubule. Sertoli cells are divided into two compartments based on composition of germ cells; the basal compartment contains spermatogonia and early spermatocytes, while the adluminal compartment contains late spermatocytes and spermatids.82 The significance of this com-partmentalization is that early germ cells are protected from many toxic agents in the blood stream by the blood-testis barrier that is operative in the basal compartment (see next section). More mature germ cells that have completed mitosis and meiosis move into the adluminal compartment.
The impact of busulfan on the testicular structure in prepubertal rats: A histological, ultrastructural and immunohistochemical study
Published in Ultrastructural Pathology, 2023
Reem Ibrahim Abd El-Hay, Walaa H.E. Hamed, Nesreen Mostafa Omar, Dalia Refat El-Bassouny, Salwa A. Gawish
Spermatogenic cells included; spermatogonia, primary spermatocytes, spermatids and spermatozoa. Spermatogonia had scanty cytoplasm and included dark type A and pale type A resting on the basement membrane. Dark type A spermatogonia had oval dark nuclei and pale type A spermatogonia showed pale oval nuclei. Type B spermatogonia were hardly differentiated. Primary spermatocytes were the largest spermatogenic cells. They appeared rounded in shape and had central rounded vesicular nuclei showing a characteristic reticular network of chromatin. Two forms of spermatids were seen; round or early spermatids with rounded pale nuclei and elongated or late spermatids with elongated darkly stained nuclei. Mature spermatozoa were present in the lumina of many the seminiferous tubules. Sertoli cells showed pale basophilic cytoplasm and oval pale nuclei near the basement membrane with prominent nucleoli.
Aluminum reproductive toxicity: a summary and interpretation of scientific reports
Published in Critical Reviews in Toxicology, 2020
Robert A. Yokel
The testes (singular testis) have two primary functions, to produce sperm and hormones including testosterone. The testes are composed of multiple seminiferous tubules and interstitial tissue, housed within a fibrous covering, the tunica albuginea. During embryonic development within the seminiferous germinal epithelium, Sertoli cells, which surround the developing germ cells, associate with the latter to form seminiferous tubules after birth. The seminiferous tubules are coiled masses that produce sperm cells through spermatogenesis, the maturation of germ cells to haploid spermatozoa. At birth, the seminiferous tubules contain spermatogonial stem cells. During the first round of spermatogenesis, Sertoli cells join to form tight junctions that compartmentalize the seminiferous epithelium into basal and luminal compartments. Spermatogonia, which are in the basal compartment, divide into type A spermatogonia that remain to replenish the precursor cells or type B spermatogonia. The latter, through meiosis in the luminal compartment, become (primary) spermatocytes. These divide to form secondary spermatocytes which meiotically divide to from spermatids, which are initially round. Multinucleated giant cells in the seminiferous tubules are degenerating germ cells. Spermatids become spermatozoa during late spermatogenesis.
Autophagy in male reproduction
Published in Systems Biology in Reproductive Medicine, 2019
Yinci Zhu, Qingqing Yin, Dandan Wei, Zhenyu Yang, Yanzhi Du, Yi Ma
Spermatogenesis is a complex process in which successive cellular events occur sequentially in specific regions of the testis. It includes the mitosis of the spermatogonia, two meiotic divisions of the spermatocytes, spermiogenesis and spermiation. During this process, the germ cells are transported across the seminiferous epithelium by the Sertoli cells (Qian et al. 2014). The seminiferous epithelium exhibits tight junctions, gap junctions and the testis-unique junctions such as the ectoplasmic specialization (ES). ES, an actin microfilament-rich anchoring junction, includes the basal ES and apical ES. The basal ES is the constructive part of the blood-testis barrier (BTB), while the apical ES facilitates the development and maturation of the spermatid (Liu et al. 2016). After the specific knockout of Atg5 or Atg7 in the mouse Sertoli cells, the apical and basal ES were disrupted, and the cytoskeleton structure was disorganized, resulting in sperm with malformed heads and low motility. Further research revealed that a negative cytoskeleton organization regulator, PDZ and LIM domain 1 (PDLIM1), was degraded by autophagy; therefore, the deficiency of autophagy led to an abnormal accumulation of PDLIM1 and then the disorder of the cytoskeleton structure and ES assembly (Liu et al. 2016).
Related Knowledge Centers
- Hermaphrodite
- Ploidy
- Seminiferous Tubule
- Spermatogonium
- Meiosis
- Germ Cell
- Gametocyte
- Testicle
- Spermatocytogenesis
- Spermatheca