Reproductive health and Gender for public heath students

Gonads and development of gonads and physiology of ovulation and spontaneous ejaculation

1. REPRODUCTIVE HEALTH AND GENDER PREPARED BY: BHIM KUMARI B.K

2. CONTENTS TO BE DISCUSSED Gonads development and functions (Ovary- ovum and Testes- sperm) Review of physiology of ovulation among girls and spontaneous ejaculation among boys

3. 2.3 Gonads development and functions (Ovary- ovum and Testes- sperm) Meaning of Gonads: A reproductive gland ( such as an ovary or testies) that produces gametes. OR, An organs that produces gametes ; a testies or ovary.

4. What is Gonads? Gonads is refer to the reproductive organs of male and female. It is a reproductive glands that is a part of the endocrine system. Male gonads are referred to as the testicles or the testes which produce testosterone ( male sex hormones). The female gonads are called the ovaries that produces estrogen and progesterone.

5. Gonads developments: In human embryonic development , gonads initially develop as undiffrentiated structures that can become either testes or ovaries .The diffrentiation into testes or ovaries is determined by genetic factors , primarily the presence or absences of the y chromosome and the SRY gene. During foetal development , around 6 week of gestation , the bipotential gonadal rindge forms in the intermediate mesoderm. The ridge contains primordial germ cells, which migrate from the yolk sac to the gonadal ridge . These germ cells eventually differentiate into either spermatozoa or ova.

6. The development of the gonads into testes or ovaries depents on the presence or absence of the SRY gene, located on the Y chromosome. If the SRY gene is present , it triggers testies development . The testes then produce testosterone , leading to the development pf male reproductive structures If SRY gene is absent , ovarian development occurs . Without testosterone, the primordial structures develop into female reproductive organs This process of sexual differentation is tightly regulated and involves complex interactions genetic , hormonal and enviranmental factors

7. Gonads development

8. Functions of Gonads Gonads helps in the maturation of the reproductive system in male and females. They produce sex hormones and gamates (sex cell) in individuals. It also helps in the development of secondary sex characteristics in men and women. gonads hepls in regulation of the reproduction process like puberty, menstruation, ovulation and sperm production.

9. Male gonads (testes) The testes — also called testicles — are two oval-shaped organs in the male reproductive system. They’re contained in a sac of skin called the scrotum. The scrotum hangs outside the body in the front of the pelvic region near the upper thighs. Structures within the testes are important for the production and storage of sperm until they’re mature enough for ejaculation. The testes also produce a hormone called testosterone. This hormone is responsible for sex drive, fertility, and the development of muscle and bone mass.

10. Testes

11. Male Gonads Hormones The male gonad hormones, also called androgen, Hormones are: Testosterone:  The testosterone hormone is produced by the testes. It is an essential hormone for physical, emotional and sexual changes in the body. Androstenedione :   Androstenedione maintains and regulates the testosterone production within the body of an individual. Inhibin :  These are the hormones that prevent the release of a (FSH). It also helps in the development and regulation of sperms.

12. Female Gonads (ovaries) Ovary plays the important role in reproduction as it produces the female reproductive cells, or  ova . Females have a pair of ovaries, held by a membrane beside the uterus on each side of the lower abdomen. During  ovulation , a follicle (a small cavity in the ovary) expels an egg under the stimulation of LH and FSH.  Follicles, or the corpus luteum in ovaries also secretes the sex hormones named: estrogen  and  progesterone. An ovary is normally firm and smooth and is about the size of an almond. Among the various reproductive tract cancers, ovarian cancer is the leading cause of death in women.

13. Ovaries

14. Female Gonad Hormones There are basically two types of female gonad hormones, estrogen, and progesterone. Estrogen:  Estrogens are female sex hormones that are responsible for reproduction in the female body. It helps in the development and growth of overall female reproductive system. Progesterone:  This hormone is responsible for preparing the uterus for conception. Progesterone regulates the uterus during the menstrual cycle . It also helps in the production of milk in the breasts during the period of pregnancy and stimulates other glands.

15. 2.4 REVIEW OF PHYSIOLOGY OF OVULATION AMONG GIRLS AND SPONTANEOUS EJACULATION AMONG BOYS PHYSIOLOGY OF OVULATION AMONG GIRLS: Ovulation,release of a mature egg from the female ovary; the release enables the egg to be fertilized by the male sperm cells. Normally, in humans, only one egg is released at one time; occasionally, two or more erupt during the menstrual cycle. Ovulation is triggered by a surge in luteinizing hormone and follicular stimulating hormones from pituitary gland.

16. The egg erupts from the ovary on the 14th to 16th day of the approximately 28-day menstrual cycle. If not fertilized, the egg is passed from the reproductive tract during menstrual bleeding, which starts about two weeks after ovulation. Occasionally, cycles occur in which an egg is not released; these are called anovulatory cycles.

17. What is the physiology of ejaculation? Ejaculation is  a physiological process heavily controlled by the autonomic nervous system . It consists of two main phases: emission and expulsion. The main organs involved in ejaculation are the distal epididymis , the vas deferens, the seminal vesicle, the prostate, the prostatic urethra, and the bladder neck 

18. Concepts of ejaculation Ejaculation is a complex process involving the nervous system, the endocrinological glands, and the contraction of various muscle groups. The culmination of this process is the expulsion of semen through the urethral meatus . Two mechanisms are responsible for provoking this expulsion: emission, followed by ejaculation.

19. Spontaneous ejaculation among boys: The SE represents  ejaculation that occurs involuntarily and in the absence of sexual excitement, desire, thoughts, or fantasies  and may stem from a variety of both psychological and physical causes including medications. Noctural emission (wet dream) may be considered a normal / physiological form of spontaneous ejaculation. Ejaculation is defined as the expulsion of seminal fluid from the urethral meatus . It involves coordinated series of reflexes activated during its two phases: emission expulsion.

20. Emission Seminal emission refers to the secretion of seminal plasma from the accessory sexual glands as the results of the peristaltic contraction of their smooth muscles; the transferring of seminal plasma and spermatozoa located into the epididymis cauda into the urethra . Thus, this process involves secretion of seminal plasma from epithelial cells and the accessory sexual glands, as well as contraction of the vas deferens to move seminal plasma and spermatozoa to the proximal urethra.

21. Simultaneously to these parasympathetic and sympathetic actions, the urethral smooth muscles contract until closing the bladder´s neck preventing, under normal circumstances, retrograde ejaculation. Once emission is completed, the ejaculate is ready to be expelled through the urethra . Expulsion: Seminal expulsion then occurs when the semen is rapidly and forcefully advanced forward along the urethra and spring out through the penile meatus

22. REFERENCE : https://www.britannica.com https://byjus.com>gonads https://www.sciencedirect.com>gonads