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Basic medicine: physiology
Published in Roy Palmer, Diana Wetherill, Medicine for Lawyers, 2020
The gonads comprise the ovaries in the female and the testes in the male. Each gonad has a dual function: to produce germ cells, i.e. ova and spermatozoa, and to secrete sex hormones. Pituitary hormones (gonadotropins) cause enlargement of the ovary and testis during childhood, and the resultant release of gonadal hormones brings about the changes of puberty, including the growth spurt and the secondary sexual characteristics of females and males. Oestrogens and progesterone secreted by the ovary cause girls to start their monthly cycle of ovulation and menstruation, while testicular androgens stimulate the production of fertile sperm and seminal fluid. If sexual intercourse takes place during the period following ovulation, when an ovum is shed from the ovary and passes down the female genital tract, then conception may take place as the sperm penetrates the ovum. The developing embryo implants into the wall of the uterus, leading to the formation of the placenta, and placental hormones then sustain the pregnancy. At birth, which occurs around 270 days later, pituitary oxytocin governs the onset of uterine contractions. The breasts have enlarged during pregnancy under the combined actions of oestrogen, progesterone and the pituitary hormone prolactin. After birth lactation is controlled by prolactin combined with oxytocin secreted as a reflex response to suckling by the infant.
Paediatric Urology
Published in Manit Arya, Taimur T. Shah, Jas S. Kalsi, Herman S. Fernando, Iqbal S. Shergill, Asif Muneer, Hashim U. Ahmed, MCQs for the FRCS(Urol) and Postgraduate Urology Examinations, 2020
Jemma Hale, Arash K. Taghizadeh
The next consideration is the development of the gonads. Where gonads have formed abnormally there is gonadal dysgenesis. This may be complete or partial. It may result in streak gonads or in an ovo-testis combination.
Peutz−Jeghers Syndrome
Published in Dongyou Liu, Handbook of Tumor Syndromes, 2020
Although PJS-associated melanocytic macules do not develop into melanoma or other malignancy, they may be removed with laser treatment for cosmetic reasons. Given their potential to cause intussusception/obstruction/intestinal bleeding, undergo malignant transformation, or become too large for endoscopic excision, PJS polyps of >1.0 cm in size should be removed by standard endoscopy. Laparoscopic-assisted enteroscopy offers a less invasive option for polypectomy. Double-balloon endoscopy (DBE) or balloon-assisted enteroscopy with or without laparotomy is an effective and safe procedure for removing large (3.0–5.0 cm in size) and distal small-bowel polyps, obviating the need for intraoperative enteroscopy or enterotomy. Instead of endoscopic approach, surgical technique (reduction, enterotomy and polyp resection) is recommended for treatment of acute intussusception with intestinal obstruction caused by large PJS polyps. Gonadal tumors in males and females are managed through conservative measures. Prophylactic hysterectomy and bilateral salpingo-oophorectomy may be considered for women with gynecologic malignancy [1].
Construction and cryopreservation of an artificial ovary in cancer patients as an element of cancer therapy and a promising approach to fertility restoration
Published in Human Fertility, 2022
Jing Chen, Plamen Todorov, Evgenia Isachenko, Gohar Rahimi, Peter Mallmann, Vladimir Isachenko
Cancer treatment requires large doses of chemotherapy and radiation therapy, leading to long-term side effects in cancer patients, which may include gonadal damage, especially in women of reproductive age (Salama et al., 2019). Among the many cancer survivor women that attend clinics for consultation, most are concerned about ovarian failure induced by cancer treatment, which is associated with infertility, menopausal symptoms, osteoporosis, endocrine dysfunction, low self-esteem, and decreased quality of life (QoL). These side effects are mainly related to the type and stage of cancer, the type and dose of cancer therapy drugs, and the age at which a patient begins the treatment (Campbell & Woodard, 2020). Since the success rate of assisted reproduction is reduced after cancer treatment, early referral to fertility preservation is urgent for female cancer patients (Salama et al., 2019).
The Role of testosterone treatment in patients with metabolic disorders
Published in Expert Review of Clinical Pharmacology, 2021
Giovanni Corona, Giulia Rastrelli, Linda Vignozzi, Arcangelo Barbonetti, Alessandra Sforza, Edoardo Mannucci, Mario Maggi
The testis, the male gonad, is characterized by the production of gametes [spermatozoa] and hormones, from the tubular and interstitial compartments, respectively. Two pituitary hormones mainly control testicular activity: follicular stimulating hormone [FSH] and luteinizing hormone [LH]. The main hormones released by the testis are androgens, and, in particular, testosterone [T], which circulates only in a minor fraction as unbound to some proteins, including albumin and sex hormone-binding globulin [SHBG]. SHBG binds T with high affinity, most probably preventing biological action. In fact, according to the free hormone hypothesis, only unbound [free] T [FT] is able to bind with the androgen receptor [AR]. T concentrations show wide fluctuations over an entire lifespan, with elevated levels in the first postnatal period [mini-puberty] that decline thereafter before surging again during puberty. Several population-based studies have documented that in adult men T levels show a progressive decline as a function of age [1,2]. However, the apparent age-associated decline in serum T is attributable to a range of chronic conditions, which are more frequent with increasing age, including obesity and metabolic derangements. In fact, T levels can remain within the normal range in older healthy men [2]. Obesity-associated reduction of SHBG could partially explain the apparent decline in total T observed in aged subjects [2].
Effects of 1.5-GHz high-power microwave exposure on the reproductive systems of male mice
Published in Electromagnetic Biology and Medicine, 2021
Guofu Dong, Hongmei Zhou, Yan Gao, Xuelong Zhao, Qi Liu, Zhihui Li, Xi Zhao, Jiye Yin, Changzhen Wang
Testosterone is mainly secreted by Leydig cells, a small amount of which comes from the adrenal cortex. It is the most active hormone in androgens. Its main physiological function is to maintain normal gonadal function. In terms of detection results, there was no significant difference between the groups at different times after exposure. It should be noted that the values for the L group at three days and seven days post-exposure were high compared to the values for the other groups, but there was no significant difference between the L group and other groups. This could be because of significant individual differences in serum testosterone levels across the mice. The results showed that 1.5-GHz microwave exposure at 3, 6, and 12 W/Kg for 30 min did not significantly influence the secretion of testosterone in mice (Table 1).