| MEDICAL ANIMATION TRANSCRIPT: The prostate is part of the male reproductive system. It produces prostatic fluid, a component of semen that carries sperm during ejaculation. The urethra, a tube that carries urine from the bladder through the penis and out of the body, passes through the prostate. Prostate tissue is divided into several functional zones: the transition zone, central zone, and peripheral zone. The prostate consists of secretory glands and ducts surrounded by vibro-muscular tissue called the stroma. Throughout life, the male sex hormone, testosterone, influences prostate growth and development. Prostatic stromal cells express an enzyme that converts testosterone to dihydrotestosterone. Dihydrotestosterone binds to stromal cells, releasing signaling factors that stimulate prostatic cell division and growth. As men age, dihydrotestosterone can accumulate among prostate cells. In addition, circulating testosterone levels fall and estrogen levels rise. These hormonal changes may lead to excessive prostatic cell growth, characteristic of benign prostatic hyperplasia and prostate cancer. In benign prostatic hyperplasia, the glandular epithelium and stroma proliferate in the transition zone and form nodules that expand the tissue. Over time, the enlarged tissue compresses the urethra and prevents normal urination. In contrast, prostate cancer commonly occurs in the peripheral zone, in which the glandular epithelial cells mutate and divide in an uncontrolled manner. Many new abnormal glands and one or more malignant tumors develop. The large tumors may compress the urethra and disrupt the urine stream. In a process called metastasis, the tumor cells spread to tissues both near and distant from the prostate. Treatment for benign prostatic hyperplasia may include medications such as 5-alpha reductase inhibitors, which block the enzymatic conversion of testosterone to dihydrotestosterone. As a result, the excess stromal and epithelial growth stops, and the prostate shrinks. One treatment for prostate cancer is radical prostatectomy, a procedure in which the entire prostate and select surrounding tissues are surgically removed. Other treatments for prostate cancer include chemotherapy, hormone therapy, radiation therapy, and other surgical procedures such as transurethral resection of the prostate, or TURP. ♪ [music] ♪ |
