Human reproduction

Human reproduction is a biological process that typically occurs through sexual activity and results in human fertilization. The process involves the union of male and female gametes, the sperm and the ovum, to produce a fertilized egg, or zygote, that can develop into a new individual with a unique genetic identity.

Biological life cycle of humans 2

Male Reproductive System

The male reproductive system is designed to produce and deliver sperm. The key parts of the male reproductive system include the testes, where sperm are produced; the epididymis, where sperm mature and are stored; and the penis, which is involved in sexual intercourse.

Spermatogenesis

Spermatogenesis is the process by which spermatozoa are produced from male primordial germ cells in the testicles. This process starts with the division and differentiation of the spermatogonium into a primary spermatocyte, which then undergoes two rounds of division to produce four haploid spermatids. These spermatids then mature into spermatozoa, the mature male gametes.

Female Reproductive System

The female reproductive system is designed to produce eggs (ova), facilitate fertilization, and carry a pregnancy to term. Key parts include the ovaries, which produce eggs and hormones; the fallopian tubes, where fertilization occurs; the uterus, where the fertilized egg implants and develops; and the vagina, which is involved in sexual intercourse and childbirth.

Oogenesis

Oogenesis is the process by which the female gametes or ova are produced in the ovaries. This process begins in the fetal stage of development with the formation of primary oocytes. These oocytes remain in a state of arrested development until puberty, when hormonal changes trigger the completion of meiosis and the formation of a secondary oocyte and polar bodies.

Fertilization and Pregnancy

• Fertilization is the fusion of the male and female gametes to form a zygote. This typically occurs in the fallopian tube and results in a combination of the genetic material from each parent. The zygote then travels to the uterus, where it implants into the uterine wall and begins to develop into an embryo through the process of embryogenesis.
• Pregnancy is the period during which a fertilized egg develops into a new individual. This period is typically divided into three trimesters, each with its own set of developmental milestones. The process concludes with childbirth, the expulsion of the newborn from the mother's body.

Contraception and Family Planning

• Contraception refers to methods used to prevent pregnancy. There are many types of contraception, including hormonal methods (like birth control pills), barrier methods (like condoms), and intrauterine devices.
• Family planning involves making informed decisions about when and whether to have children, and how many to have. It often involves the use of contraception to control fertility.

References

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• Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. Sperm. Available from: https://www.ncbi.nlm.nih.gov/books/NBK26914/
• Human Reproduction: Updates and New Horizons by Heide Schatten (2017). John Wiley & Sons. ISBN 978-1-119-29970-3.
• Larsen's Human Embryology (5th ed.). Philadelphia: Churchill Livingstone. 2015. ISBN 978-1-4557-0682-0.
• Contraception and family planning. (2018). In Planned Parenthood.

Human reproduction Resources
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