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Introduction
Humans are sexually reproducing and viviparous, which means they have two parents. Aspects of human reproduction that are observed include the formation of gametes (gametogenesis), which are sperms in males and an egg in females, the transfer of sperms into the female genital tract (insemination), and the fusion of male and female gametes (fertilisation), which results in the formation of the zygote. Embryonic development (gestation) and the delivery of the baby are the next steps, which are followed by the formation and development of the blastocyst and its attachment to the uterine wall (implantation) (parturition). You’ve learned that these reproductive activities take place after the age of puberty. When comparing the reproductive events in males and females, there are significant differences. For example, sperm formation can continue even in old men, whereas ovum formation stops when a woman reaches the age of fifty.
There are two types of reproduction: asexual reproduction and sexual reproduction.
Sexual Reproduction – This process of reproduction is quite complex, and it begins with the formation and transfer of gametes, followed by fertilisation, the formation of the zygote, and the development of the embryo, among other things.
In this type of reproduction, only one parent is involved, and the new offspring generated is genetically similar to the parent (asexual reproduction).
The Male Reproductive System
The male reproductive system is situated within the pelvic region of the male body. There are two testicles, as well as accessory ducts, glands, and the external genitalia, in the male genitalia.
Located outside of the abdominal cavity in a pouch known as the scrotum, the testicles are responsible for reproduction. The scrotum contributes to the preservation of the low temperature of the testicles (2–2.5) C lower than the usual internal body temperature), which is necessary for spermatogenesis to take place there.
Each testis in an adult is oval in shape, with a length of approximately 4 to 5 cm and a width of approximately 2 to 3 cm. The testicles are protected by a thick layer of tissue. Each testis contains approximately 250 compartments, which are referred to as testicular lobules. Each lobule includes one to three seminiferous tubules, which are heavily coiled and in which sperms are formed.
Male germ cells (spermatogonia) and Sertoli cells line the inside of each seminiferous tubule, which serves as a barrier between the male germ cells and the rest of the body. Male germ cells go through meiotic divisions, which eventually result in the creation of sperm, whereas Sertoli cells offer sustenance to the germ cells during this process. Small blood arteries and interstitial cells, also known as Leydig cells, are found in the spaces between the seminiferous tubules, which are referred to as interstitial spaces.
Leydig cells are responsible for the synthesis and secretion of testicular hormones known as androgens. Other immunologically capable cells can be found in the body as well. Included among these are the rete testis, vasa efferentia, epididymis, and the vas deferens (also known as the male sperm canal).
The seminiferous tubules of the testis open into the vasa efferentia through the rete testis, which is a small opening in the testis. Upon leaving the testis, the vasa efferentia opens into the epididymis, which is found along the posterior surface of each testis. The epididymis connects to the vas deferens, which ascends to the abdomen and loops around the urine bladder to exit the body. In addition, it is connected to the ejaculatory canal, which opens into the urethra via the seminal canal. These ducts are responsible for storing and transporting sperm from the testicles to the outer world through the urethra.
The Female Reproductive System
Women’s reproductive systems consist of a pair of ovaries and a pair of oviducts, as well as the uterus, cervix, vagina, and the external genitalia, all of which are located in the pelvic area. These components of the system, as well as a pair of mammary glands, are physically and functionally linked to support the processes of ovulation, fertilisation, pregnancy, birth, and child rearing.
The ovaries are the primary female sex organs, and they are responsible for the production of the female gamete (ovum) as well as many steroid hormones (ovarian hormones). The ovaries are found on either side of the lower abdomen, one on each side of the lower abdomen. It is estimated that each ovary measures 2 to 4 cm in length and that it is attached to the pelvic wall and uterus through ligaments.
Each ovary is covered by a thin epithelium that encloses the ovarian stroma and protects it from the environment. The stroma is separated into two zones – a peripheral cortex and an interior medulla – that are responsible for different functions.
The female accessory ducts are the oviducts (fallopian tubes), the uterus, and the vaginal canal. Each fallopian tube is approximately 10-12 cm long and extends from the border of each ovary to the uterus; the infundibulum, which is the funnel-shaped portion closest to the ovary, is the longest component of the tube.
During ovulation, the infundibulum has finger-like extensions called fimbriae that aid in the gathering of the ovum after it has been released from the egg. The infundibulum connects to the ampulla, which is a larger section of the oviduct. The isthmus, which is the final section of the oviduct, has a narrow lumen and connects to the uterus.
The uterus is a single organ that is also referred to as the womb. It is shaped like an inverted pear, and it contains the uterus. The ligaments that join to the pelvic wall provide support for the organ. A thin cervix separates the uterus from the vaginal opening. The cavity of the cervix is referred to as the cervical canal, and it, together with the vagina, forms the birth canal. The uterine wall is composed of three layers of connective tissue.
The uterine cavity is lined by three layers of tissue: the external thin membrane perimetrium, the middle thick layer of smooth muscle, the myometrium, and the inner glandular layer known as the endometrium. During the menstrual cycle, the endometrium goes through cyclical changes, whereas the myometrium goes through a period of intense contraction during the delivery of the baby.
The external genitalia of a female are the mons pubis, labia majora, labia minora, hymen, and clitoris. Located between the thighs, the mons pubis is a cushion of fatty tissue covered by skin and pubic hair. The labia majora are fleshy folds of tissue that stretch down from the mons pubis and surround the vaginal opening on either side of the body.
The labia minora are a pair of folds of tissue located beneath the labia majora that are coupled with one another. The opening of the vaginal canal is frequently partially covered by a membrane known as the hymen. Clutius is a little finger-like structure that lies at the top junction of the two labia minora, above the urethral entrance, and is a part of the reproductive system.
Conclusion
Men and women can mate, fertilise internally, and support the growth and development of their offspring because of the reproductive organs that have evolved in land animals. Gametogenesis, the production of sperm (spermatogenesis) and eggs (oogenesis), takes place through the process of meiosis.
In both men and women, hormones released by the hypothalamus and anterior pituitary, as well as hormones released by reproductive tissues and organs, regulate the length and timing of their menstrual cycles. This group of hormones is responsible for the regulation of the female reproductive cycle, which is separated into the ovarian cycle and the menstrual cycle.
Pregnancy in humans begins with the fertilisation of an egg and continues through the three trimesters of the gestational period. The first trimester is responsible for the formation of the body’s fundamental structures, which include the limb buds, heart, eyes, and liver. The development of all of the organs and systems continues during the second trimester of pregnancy.
A woman’s third trimester is marked by the greatest growth of her foetus, which culminates in her labour and birth. Three steps (contractions, delivery of the foetus, and ejection of the placenta) are involved in the labour process, and each stage is accelerated by hormones.
