Reproductive Biology

Explore the male reproductive system anatomy, including testes, scrotum, and external and internal genitalia, and learn how temperature regulation via cremaster muscle and pampiniform plexus protects sperm.

Learn how male accessory glands—the seminal vesicles, prostate, and bulbourethral glands—deliver seminal fluid rich in fructose, clot semen, liquefy it, and aid sperm transport and fertilization.

Discover the four stages of spermatogenesis—from mitotic proliferation of spermatogonia to the formation of haploid spermatozoa—driven by FSH, growth hormone, and testosterone, with details on sperm structure and chromosomal content.

Learn the composition of semen, including seminal fluid, prostate fluid, and bulbourethral fluid, and identify normal sperm counts. Analyze key semen parameters: volume, pH, liquefaction, morphology, motility, and viability.

Learn the stages of the male sexual act—arousal, lubrication, emission, ejaculation, and resolution. See how parasympathetic and sympathetic nerves regulate penile engorgement via nitric oxide and pelvic muscles.

Explores how testosterone and dihydrotestosterone drive male differentiation and puberty, from fetal sex differentiation and descent of testes to hair, voice, and muscle changes, via Leydig cells and LH/FSH signaling.

Explore erectile dysfunction, defined as insufficient penile rigidity for intercourse, and its causes—from vascular and nervous system issues to low testosterone—along with treatments using PDE5 inhibitors like Viagra.

Prostate cancer stems from abnormal growth of prostate cells, may be localized or metastatic to bones or nerves, causing urinary symptoms and treatment with drugs, chemotherapy, or surgery—early detection matters.

Explore retrograde ejaculation and anejaculation, detailing bladder neck failure, semen misrouting into the bladder, and factors like spinal cord injury, prostate inflammation, infections, drugs, and pelvic surgery.

Describe cryptorchidism as retention of testes in the lower abdomen or between the inguinal canal and scrotum, with testosterone aiding descent and possible surgery or testosterone administration.

Explore how male hypogonadism reduces gonadal function, alters testosterone levels and puberty progression, and affects secondary sexual characteristics and bone development, with eunuchism and gonadotropin regulation discussed.

Explore the ovary as the primary female reproductive organ with cortical follicles containing eggs, and how ovulation releases a mature egg under FSH and LH.