Male Reproductive System: Anatomy and Function

• Male reproductive system's primary biological function is reproduction.
• This involves various stages and organs, activated by the secretion of sexual hormones, preparing the body for reproduction.
• Semen and spermatozoa are produced in the testicles and prostate over 10-14 days.
• Erection occurs by blood filling the penis, followed by ejaculation through the urethra after intercourse/orgasm.
• The male reproductive system consists of internal and external organs and ducts.

External Organs

• Testicles produce male sex hormones (testosterone) and spermatozoa (reproductive cells), housed and protected by the scrotum (skin and tissue envelope).
• The penis acts as the system's copulatory organ, consisting of:
  • The glans, which is the tip containing sensitive regions.
  • The corpus spongiosum, a tissue supporting the urethra that forms part of the glans.
  • The corpora cavernosa, located on the upper part of the penis, fill with blood provide hardness and firmness during erection.
• The penis is typically covered by the foreskin and also functions to expel urine.
• The epididymis matures and activates sperm.
• The vas deferens connect the epididymis to the ejaculatory ducts, allowing semen to exit.

Internal Organs

• Seminal vesicles produce an alkaline, viscous fluid which neutralizes urethral acidity, protects spermatozoa, and accounts for 40% of semen volume, located near the prostate behind the bladder.
• The prostate gland, exclusive to males, is located behind the rectum at the base of the bladder and produces seminal content that nourishes sperm and prevents urine release during sex.
• The urethra carries urine out of the body and transports semen out of the body during ejaculation.
• Bulbourethral glands (Cowper's glands) secrete pre-seminal fluid that cleans and neutralizes the acidity of the urethra, facilitating ejaculation.

Female Reproductive System

• The female reproductive system consists of organs, tissues, and ducts that enable sexual reproduction in female humans (and other higher animals).
• Crucially important for procreation, it facilitates fertilization and houses/nurtures the developing individual until gestation completes.
• The female genital system includes various organ sets, glands, and ducts.
• Most of the female genital system is internal.

Internal Organs of the Female Reproductive System

• The vagina serves as the passageway for penis entry, providing essential lubrication and secretion during intercourse. It expands to allow childbirth after pregnancy.
• The uterus is the sac where fertilization occurs, housing and gestating the fetus until birth.
• The ovaries generate eggs, preparing them for release into the uterus monthly, and produce hormones for sexual development.
• The fallopian tubes (10-13 cm long) connect the ovaries to the uterus, the site where fertilization occurs (rarely does the zygote implant there).

Chromosome System

• A chromosome is a component containing the DNA in cells.
• Chromosomes are structurally sophisticated elements that contain replication and segregation processes.
• Each species has a unique set of chromosomes based on number and arrangement.
• Humans have 23 pairs of chromosomes, 22 pairs of autosomes numbered 1-22 and one pair of sex chromosomes, X and Y.
• Each parent donates a chromosome from each pair to their offspring.
• Chromosomes are thread-like structures made of protein and a single DNA molecule that carries genomic information from one cell to another.
• In plants and animals, chromosomes are found in the nucleus of cells.
• Humans have 22 pairs of autosomes and one pair of sex chromosomes (XX or XY), totaling 46.
• Each pair contains two chromosomes, one from each parent, and offspring inherit half of their chromosomes from each parent.
• Chromosomes are visible under a microscope during cell division when the nucleus disassembles.