THE REPRODUCTIVE SYSTEM
Topic: Basic Anatomy and Physiology
Next Unit: The Integumentary System
7 minute read
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 itself is composed of specialized venous tissue that can become engorged with blood to both 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 delviery.
- 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 2 arteries: "A-V-A.".)
- MEMBRANES: also called the amnion or amniotic sac acts to protect the fetus from both physical trauma and infection as well as having 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.
Both the male and the 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 male reproductive tract (testicles and penis) is connected by the vas deferens and urethra. The first is exclusively for carrying sperm and seminal fluid, while the latter carries urine along with the after-mentioned sperm and seminal fluid.