The REPRODUCTIVE, or GENITOURINARY, system encompasses the internal and external structures required for reproduction. It is closely related to the renal and endocrine systems.

Internal and External Structures of the Male Reproductive System

The male reproductive system consists of the

• PENIS and
• TESTES, with the
• PROSTATE a secondary lubrication and fluid producing organ.

The major hormone released by the testicles is testosterone, which influences the body to develop the traditionally masculine traits (body hair, dense muscles, and defined bones.) The testicles are temperature sensitive and are kept at a near-ideal temperature by hanging further away from the body when it is warm and retracting closer in cold environments.

The penis is composed of specialized venous tissue that can become engorged with blood to ease the process of intercourse and heighten sensation.

Internal and External Structures of the Female Reproductive System

The female reproductive system is more complex than the male system, given the multiple structures (vagina, cervix, uterus, fallopian tubes, and ovaries) and the cyclic effects upon it by the menstrual cycle. 

• The OVARIES are the major producers of hormones and gametes (eggs or ova). Along with the more numerous hormones (e.g., Estrogen, Progesterone), ovarian function is dramatically tied into the pituitary system through fluctuating levels of controlling hormones in a complex maintenance "feedback" system.
• UTERUS and CERVIX: play a major role in gestation and subsequent delivery.
• VAGINA, LABIA, EXTERNAL GLANDS: Primary function is intercourse/sensation.

Structures of Pregnancy

The key structures in pregnancy are the placenta, umbilical cord, and membranes (amnion/chorion.)

• PLACENTA: acts as a fetus's lungs and intestines, exchanging oxygen and nutrients with the maternal blood while keeping them separate. There is no direct mixing of maternal and fetal blood. All exchange via biochemical filtration or active transport.
• UMBILICAL CORD: connects the placenta to the fetus via the umbilical vein and arteries. The vein carries oxygenated blood from the placenta to the baby, and the arteries carry deoxygenated blood and waste to the placenta. (One vein and two arteries: "A-V-A.".)
• MEMBRANES: also called the amnion or amniotic sac, it protects the fetus from both physical trauma and infection and has amniotic fluid that takes part in fetal lung maturation. At the time of birth, the membranes rupture, uterine contractions expel the fetus, and the placenta is likewise expelled soon after.

Secondary Functions

The male and female reproductive systems are intimately associated with the production of gametes and sex-related hormones. The male reproductive system is more closely intertwined with the renal/urinary system than the reproductive tract of females since gametes (spermatozoa) are passed to the urethra for expulsion (ejaculation). The vas deferens and urethra connect the male reproductive tract (testicles and penis). The first is exclusively for carrying sperm and seminal fluid, which comes from the epididymis, while the latter carries urine along with the after-mentioned sperm and seminal fluid. 

Common Problems

Epididymitis is the inflammation of the epididymis. This is a coiled tube located on the posterior side of each testicle. The inflammation is typically the result of bacteria entering the epididymis that can occur due to a urinary tract infection (UTI) or sexually transmitted infection (STI). The pain typically begins as mild and progresses more as the inflammation increases. It can be excruciating for the patient, and treatment is generally oral antibiotics to clear up the infection and analgesics for pain. The age group this affects the most can range from 14-19 years of age in males.

BPH, or Benign Prostate Hyperplasia, results in rapid prostate enlargement, which lies below the bladder and surrounds the urethra. BPH can eventually result in blockage of the urethra, leading to urinary retention. This condition usually progresses slowly, resulting in difficulty initiating a stream, leaking urine, and pelvic pain.

Uncommon Problems

Testicular torsion is an uncommon occurrence, found more in younger boys than adolescent males and even more rare in adult males. This and other structural problems are addressed in more detail in the Male Genitourinary Conditions Unit, and explain that it causes significant pain and even death of the testicle if not promptly recognized and diagnosed. However, in the extreme case that the patient requires the removal of a single testicle, as the result of tissue death due to torsion, this does not significantly impact, if any impact at all, the insemination future of young boys. Even so, the older the patient is beyond boyhood, the greater the impact. Long story short, early recognition is KEY. Always err on the side of caution with these patients.