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Published in Asim Kurjak, Ultrasound and Infertility, 2020
Joseph G. Schenker, Aby Lewin, Menashe Ben-David
The functions of the testis are spermatogenesis, which takes place in the germinal epithelium of seminiferous tubules and steroidogenesis, which takes place in the interstitial cells (Leydig). The regulation of testicular function is controlled by an interaction between the CNS, hypothalamus, hypophysis, and testis. The spermatogenesis in man requires a period of 70 ± 5 d. The passage of sperm through the epididymis and vas deferens varies with the mean time of 12 d. It is not a single process of transport, but it is vital to allow further sperm maturation and development of sperm motility. The process of ejaculation is controlled by the nervous system and involves the secretion of prostate, testicular, and seminal vesicular components.
Toxic Responses of the Male Reproductive System
Published in Stephen K. Hall, Joana Chakraborty, Randall J. Ruch, Chemical Exposure and Toxic Responses, 2020
The Sertoli cells are relatively few in number. They are tall cells with branch-like projections (Figure 13.1c). Each Sertoli cell extends from the base of the seminiferous tubules to the lumen. The germ cells are present in indentations of the Sertoli cells. In the adult seminiferous tubules, the Sertoli cells do not divide. They play a coordinating role. The Sertoli cells maintain contacts with their neighboring cells via gap junction. Thus they are active in the information transfer system around and along the seminiferous tubules. Sertoli cells maintain the overall architecture of various layers of germ cells; they secrete fluid and some important proteins, including androgen-binding protein; they play an active role in the release of spermatozoa into the lumen of the seminiferous tubule.
Reproduction, development and work
Published in Chris Winder, Neill Stacey, Occupational Toxicology, 2004
The testes are covered by a protective dense connective tissue, the tunica albuginea. Extensions of this tissue form septa inside the testis dividing it into a number of lobes. Each lobe contains 1–4 tightly coiled seminiferous tubules. The tubules are lined with germinal epithelium, which consists of two basic cell types: the sustentacular or Sertoli cells which have a supportive function; and the seminiferous tubules where sperm are produced. In between the tubules are the interstitial cells which produce testosterone. The seminiferous tubules empty into another set of tubules, the rete testis. From the rete the sperm travel into the epididymis located outside the testes.
The combined effects of noise and vibration stress on sex hormone levels, fertility capacity, and the protective role of cinnamon extract in rats: an experimental study
Published in Archives of Environmental & Occupational Health, 2022
Hamideh Pirami, Ali Khavanin, Farshad Nadri, Ali Tajpoor, Younes Mehrifar, Zohreh Mazaheri Tirani
Physiological levels of LH, FSH, and testosterone play key roles in spermatogenesis, and decreased levels of these hormones can be an important factor in structural changes in seminiferous tubules and damage to testicular tissue. Spermatogenesis is a very dynamic process that is sensitive to stressors, so oxidative stress can have adverse effects on spermatogenesis and Leydig cells.59 Stress activates the hypothalamic-pituitary-adrenal axis (HPA axis), which induces an increase in glucocorticoid release and a decrease in testosterone production in Leydig cells by the glucocorticoid receptor. In stressful situations, it increases the secretion of androgens secreted by the adrenal glands, such as dehydroepiandrosterone (DHEA), which through a negative feedback mechanism leads to a decrease in testosterone production.60
Hyperlipidemia and male infertility
Published in Egyptian Journal of Basic and Applied Sciences, 2021
Zainab Bubakr Hamad Zubi, Hamad Abdulsalam Hamad Alfarisi
Testicular tissue consists of seminiferous tubules that constitute approximately 80% of the testicular mass. It is the site of spermatogenesis. Between the seminiferous tubules located Leydig or interstitial cells, which is the site of testosterone production [15]. Behind each testis there is an epididymis which is a convoluted tubule with three parts; head (caput), body (corpus) and tail (cauda). It is lined by epithelial cells that have secretory and absorptive functions maintaining sperm in a viable and immotile status and enhance their maturation [16]. Sperm consists of a head, neck and tail (midpiece and principal piece) [17]. The sperm head composed of three parts; the nucleus, the acrosome and the perinuclear theca [18]. Movement of sperm is provided by the tail. Sperm mitochondria are concentrated within the midpiece [19].
A male germ cell assay and supporting somatic cells: its application for the detection of phase specificity of genotoxins in vitro
Published in Journal of Toxicology and Environmental Health, Part B, 2020
Khaled Habas, Martin H. Brinkworth, Diana Anderson
Leydig cells, also known as interstitial cells of Leydig, regulate development of spermatogenesis in seminiferous tubules through secretion of growth factors and hormones which are responsible for steroidogenesis and male germ cell development (Heinrich and DeFalco 2019). In a rodent, Leydig cells are formed as functionally and morphologically different generations. The fetal Leydig cell as the first generation develops in utero from undifferentiated stem Leydig cells (SLCs) (Dong et al. 2007). Leydig cells are primary endocrine cells that produce androgens in men. Increased glucocorticoid levels were found to be associated with decreased serum testosterone (T) levels and dysfunctional male reproduction (Monder et al. 1994; Smals, Kloppenborg, and Benraad 1977).