Reproductive 

Ovaries Are Dynamic: At birth, a female has around 1 to 2 million eggs in her ovaries. However, by the time she reaches puberty, this number decreases to about 300,000 to 400,000. Only about 400 of these will be released during a woman's lifetime.

Egg Release (Ovulation): Ovulation occurs approximately once a month, during which a mature egg is released from one of the ovaries. This egg travels down the fallopian tube and may be fertilized by sperm.

Fimbriae: The fimbriae are finger-like projections at the end of the fallopian tube closest to the ovary. They help to catch the released egg and transport it into the fallopian tube.

Uterine Contractions: During menstruation, the uterus contracts to help shed its lining. These contractions can be felt as menstrual cramps.

Longest and Shortest Cells: The female reproductive system produces both the smallest cell (the egg) and the largest cell (the ovum) in the human body.

Menstrual Cycle: The menstrual cycle is regulated by a complex interplay of hormones, including estrogen and progesterone. It typically lasts around 28 days, although it can vary widely among individuals.

Vaginal pH: The pH level of a healthy vagina is acidic, usually ranging from 3.8 to 4.5. This acidic environment helps protect against harmful bacteria and infections.

Egg Lifespan: An unfertilized egg has a lifespan of about 12 to 24 hours after ovulation. If it is not fertilized during this time, it disintegrates.

Cervical Mucus Changes: The consistency and color of cervical mucus change throughout the menstrual cycle. Around ovulation, it becomes more clear and slippery to facilitate sperm travel.

Pregnancy Hormones: During pregnancy, the placenta produces hormones that help sustain the pregnancy. These include human chorionic gonadotropin (hCG), which is what pregnancy tests detect.

Continuous Sperm Production: Unlike women, who are born with a finite number of eggs, men continually produce sperm throughout their lives. The process of sperm production, called spermatogenesis, takes place in the testes.

Sperm Count: A healthy male can produce up to 100 million sperm per day. However, it only takes one sperm to fertilize an egg.

Epididymis Storage: After sperm is produced, it's stored in the epididymis, a coiled tube located on the back of each testicle. This is where sperm gain the ability to swim and fertilize an egg.

Seminal Vesicles Contribution: Seminal vesicles, located near the prostate gland, produce about 70% of the fluid that makes up semen. This fluid provides nutrients and energy for sperm.

Prostate Gland's Role: The prostate gland secretes a milky alkaline fluid that constitutes about 30% of semen. This fluid helps neutralize the acidity of the female reproductive tract, providing a more hospitable environment for sperm.

Vasectomy: A vasectomy is a surgical procedure in which the vas deferens, the tubes that carry sperm from the testicles to the urethra, are cut or blocked. This is a permanent form of male contraception.

Testosterone Production: The testes not only produce sperm but also secrete testosterone, the primary male sex hormone. Testosterone plays a crucial role in male sexual development and reproductive health.

Scrotum Temperature Regulation: The scrotum, where the testicles are located, hangs outside the body to maintain a slightly lower temperature than the rest of the body. This is essential for optimal sperm production.

Penis Anatomy: The penis contains three cylindrical bodies of spongy tissue. Two of them, called the corpora cavernosa, run along the top side, and one, called the corpus spongiosum, surrounds the urethra.