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The prostate is an accessory gland of the male reproductive system and a muscle-driven mechanical switch between urination and ejaculation. It is found in all male mammals. It differs between species anatomically, chemically, and physiologically. Anatomically, the prostate is found below the bladder, with the urethra passing through it. It is described in gross anatomy as consisting of lobes and in microanatomy by zone. It is surrounded by an elastic, fibromuscular capsule and contains glandular tissue, as well as connective tissue.
The prostate produces and contains fluid that forms part of semen, the substance emitted during ejaculation as part of the male sexual response. This prostatic fluid is slightly Alkalinity, milky or white in appearance. The alkalinity of semen helps neutralize the acidity of the vagina, prolonging the lifespan of sperm. The prostatic fluid is expelled in the first part of ejaculate, together with most of the sperm, because of the action of smooth muscle tissue within the prostate. In comparison with the few spermatozoa expelled together with mainly seminal vesicular fluid, those in prostatic fluid have better sperm motility, longer survival, and better protection of genetic material.
Disorders of the prostate include enlargement, inflammation, infection, and prostate cancer. The word prostate is derived from Ancient Greek (προστάτης), meaning "one who stands before", "protector", "guardian", with the term originally used to describe the seminal vesicles.
The internal structure of the prostate has been described using both lobes and zones. Because of the variation in descriptions and definitions of lobes, the zone classification is used more predominantly.
The prostate has been described as consisting of three or four zones. (2025). 9780702052309 ISBN 9780702052309 Zones are more typically able to be seen on histology, or in medical imaging, such as ultrasound or MRI.
The "lobe" classification describes lobes that, while originally defined in the fetus, are also visible in gross anatomy, including dissection and when viewed endoscopically. The five lobes are the anterior lobe or isthmus, the posterior lobe, the right and left lateral lobes, and the middle or median lobe.
Inside of the prostate, adjacent and parallel to the prostatic urethra, there are two longitudinal muscle systems. On the front side (ventrally) runs the urethral dilator ( musculus dilatator urethrae), on the backside (dorsally) runs the muscle switching the urethra into the ejaculatory state ( musculus ejaculatorius).Michael Schünke, Erik Schulte, Udo Schumacher: PROMETHEUS Innere Organe. LernAtlas Anatomie, vol 2: Innere Organe, Thieme Verlag, Stuttgart/Germany 2012, , p. 298, PDF.
The veins of the prostate form a network – the prostatic venous plexus, primarily around its front and outer surface. This network also receives blood from the deep dorsal vein of the penis, and is connected via branches to the vesical plexus and internal pudendal veins. Veins drain into the Vesical veins and then internal iliac veins.
The lymphatic drainage of the prostate depends on the positioning of the area. Vessels surrounding the vas deferens, some of the vessels in the seminal vesicle, and a vessel from the posterior surface of the prostate drain into the external iliac lymph nodes. Some of the seminal vesicle vessels, prostatic vessels, and vessels from the anterior prostate drain into internal iliac lymph nodes. Vessels of the prostate itself also drain into the obturator and sacral lymph nodes.
The connective tissue of the prostate is made up of fibrous tissue and smooth muscle. The fibrous tissue separates the gland into lobules. It also sits between the glands and is composed of randomly orientated smooth-muscle bundles that are continuous with the bladder.
Over time, thickened secretions called corpora amylacea accumulate in the gland.
The prostatic part of the urethra develops from the middle, pelvic, part of the urogenital sinus, which is of origin. Around the end of the third month of embryonic life, outgrowths arise from the prostatic part of the urethra and grow into the surrounding mesenchyme. The cells lining this part of the urethra differentiate into the glandular epithelium of the prostate. The associated mesenchyme differentiates into the dense connective tissue and the smooth muscle of the prostate. (2025). 9781416037057, Saunders/Elsevier. ISBN 9781416037057
Condensation of mesenchyme, urethra, and gives rise to the adult prostate gland, a composite organ made up of several tightly fused glandular and non-glandular components. To function properly, the prostate needs male hormones (), which are responsible for male sex characteristics. The main male hormone is testosterone, which is produced mainly by the . It is dihydrotestosterone (DHT), a metabolite of testosterone, that predominantly regulates the prostate. The prostate gland enlarges over time, until the fourth decade of life.
In case of an operation, e.g. because of benign prostatic hyperplasia (BPH), damaging or sparing of these two muscle systems varies considerably depending on the choice of operation type and details of the procedure of the chosen technique. The effects on postoperational urination and ejaculation vary correspondingly.
Acute prostatitis and chronic bacterial prostatitis are treated with . Chronic non-bacterial prostatitis, or male chronic pelvic pain syndrome is treated by a large variety of modalities including the medications alpha blockers, non-steroidal anti-inflammatories and amitriptyline, , and other . Other treatments that are not medications may include physical therapy, psychotherapy, neuromodulation, and surgery. More recently, a combination of trigger point and psychological therapy has proved effective for category III prostatitis as well.
BPH can be treated with medication, a minimally invasive procedure or, in extreme cases, surgery that removes the prostate. In general, treatment often begins with an alpha-1 adrenergic receptor antagonist medication such as tamsulosin, which reduces the tone of the smooth muscle found in the urethra that passes through the prostate, making it easier for urine to pass through. For people with persistent symptoms, procedures may be considered. The surgery most often used in such cases is transurethral resection of the prostate, in which an instrument is inserted through the urethra to remove prostate tissue that is pressing against the upper part of the urethra and restricting the flow of urine. Minimally invasive procedures include transurethral needle ablation of the prostate and transurethral microwave thermotherapy. These outpatient procedures may be followed by the insertion of a temporary prostatic stent, to allow normal voluntary urination, without exacerbating irritative symptoms.
A digital rectal examination and the measurement of a prostate-specific antigen (PSA) level are usually the first investigations done to check for prostate cancer. PSA values are difficult to interpret, because a high value might be present in a person without cancer, and a low value can be present in someone with cancer. The next form of testing is often the taking of a prostate biopsy to assess for tumour grade and invasiveness. Because of the significant risk of overdiagnosis with widespread screening in the general population, prostate cancer screening is controversial. If a tumour is confirmed, medical imaging such as an MRI or bone scan may be done to check for the presence of tumour in other parts of the body.
Prostate cancer that is only present in the prostate is often treated with either surgical prostatectomy or with radiotherapy or by the insertion of small radioactive particles of iodine-125 or palladium-103, called brachytherapy. Cancer that has spread to other parts of the body is usually treated also with hormone therapy, to deprive a tumour of sex hormones (androgens) that stimulate proliferation. This is often done through the use of GnRH analogues or agents (such as bicalutamide) that block the receptors that androgens act on; occasionally, orchidectomy may be done instead. Cancer that does not respond to hormonal treatment, or that progresses after treatment, might be treated with chemotherapy such as docetaxel. Radiotherapy may also be used to help with pain associated with bony lesions.
Sometimes, the decision may be made not to treat prostate cancer. If a cancer is small and localised, the decision may be made to monitor for cancer activity at intervals ("active surveillance") and defer treatment. If a person, because of Frailty syndrome or other medical conditions or reasons, has a life expectancy less than ten years, then the impacts of treatment may outweigh any perceived benefits.
The whole prostate can be removed. Complications that might develop because of surgery include urinary incontinence and erectile dysfunction because of damage to nerves during the operation, particularly if a cancer is very close to nerves. Ejaculation of semen will not occur during orgasm if the vasa deferentia are tied off and seminal vesicles removed, such as during a radical prosatectomy. This will mean a man becomes infertile. Sometimes, orgasm may not be able to occur or may be painful. The penis length may shorten slightly if the part of the urethra within the prostate is also removed. General complications due to surgery can also develop, such as , bleeding, inadvertent damage to nearby organs or within the abdomen, and the formation of .
At the time, Du Laurens was describing what was considered to be a pair of organs (not the single two-lobed organ), and the Latin term prostatae that was used was a mistranslation of the term for the Ancient Greek word used to describe the seminal vesicles, parastatai; although it has been argued that surgeons in Ancient Greece and Rome must have at least seen the prostate as an anatomical entity. The term prostatae was taken rather than the grammatically correct prostator (singular) and prostatores (plural) because the noun gender of the Ancient Greek term was taken as female, when it was in fact male.
The fact that the prostate was one and not two organs was an idea popularised throughout the early 18th century, as was the English language term used to describe the organ, prostate, attributed to William Cheselden. A monograph, "Practical observations on the treatment of the diseases of the prostate gland" by Everard Home in 1811, was important in the history of the prostate by describing and naming anatomical parts of the prostate, including the median lobe. The idea of the five lobes of the prostate was popularized following anatomical studies conducted by American urologist Oswald Lowsley in 1912. John E. McNeal first proposed the idea of "zones" in 1968; McNeal found that the relatively homogeneous cut surface of an adult prostate in no way resembled "lobes" and thus led to the description of "zones".
Prostate cancer was first described in a speech to the Medical and Chiurgical Society of London in 1853 by surgeon John Adams and increasingly described by the late 19th century. Prostate cancer was initially considered a rare disease, probably because of shorter life expectancy and poorer detection methods in the 19th century. The first treatments of prostate cancer were surgeries to relieve urinary obstruction. Samuel David Gross has been credited with the first mention of a prostatectomy, as "too absurd to be seriously entertained" The first removal for prostate cancer (radical perineal prostatectomy) was first performed in 1904 by Hugh H. Young at Johns Hopkins Hospital; partial removal of the gland was conducted by Theodore Billroth in 1867.
Transurethral resection of the prostate (TURP) replaced radical prostatectomy for symptomatic relief of obstruction in the middle of the 20th century because it could better preserve penile erectile function. Radical retropubic prostatectomy was developed in 1983 by Patrick Walsh. In 1941, Charles B. Huggins published studies in which he used estrogen to oppose testosterone production in men with metastatic prostate cancer. This discovery of "chemical castration" won Huggins the 1966 Nobel Prize in Physiology or Medicine.
The role of the gonadotropin-releasing hormone (GnRH) in reproduction was determined by Andrzej W. Schally and Roger Guillemin, who both won the 1977 Nobel Prize in Physiology or Medicine for this work. GnRH receptor agonists, such as leuprorelin and goserelin, were subsequently developed and used to treat prostate cancer. Radiation therapy for prostate cancer was first developed in the early 20th century and initially consisted of intraprostatic radium implants. External beam radiotherapy became more popular as stronger X-ray radiation sources became available in the middle of the 20th century. Brachytherapy with implanted seeds (for prostate cancer) was first described in 1983. Systemic chemotherapy for prostate cancer was first studied in the 1970s. The initial regimen of cyclophosphamide and 5-fluorouracil was quickly joined by multiple regimens using a host of other systemic chemotherapy drugs.
The structure of the prostate varies, ranging from tubuloalveolar (as in humans) to branched tubular. The gland is particularly well developed in and boars, though in other mammals, such as bulls, it can be small and inconspicuous.Nelsen, O. E. (1953) Comparative embryology of the vertebrates Blakiston, page 31. In other animals, such as marsupials and small ruminants, the prostate is disseminate, meaning not specifically localisable as a distinct tissue, but present throughout the relevant part of the urethra; in other animals, such as red deer and American elk, it may be present as a specific organ and in a disseminate form. In some marsupial species, the size of the prostate gland changes seasonally. The prostate is the only accessory gland that occurs in male dogs. Dogs can produce in one hour as much prostatic fluid as a human can in a day. They excrete this fluid along with their urine to mark their territory. Additionally, dogs are the only species apart from humans seen to have a significant incidence of prostate cancer. The prostate is the only male accessory gland that occurs in cetaceans, consisting of diffuse urethral glands surrounded by a very powerful compressor muscle.Rommel, Sentiel A., D. Ann Pabst, and William A. McLellan. " Functional anatomy of the cetacean reproductive system, with comparisons to the domestic dog." Reproductive Biology and Phylogeny of Cetacea. Science Publishers (2016): 127–145.
The prostate gland originates with tissues in the urethral wall. This means the urethra, a compressible tube used for urination, runs through the middle of the prostate; enlargement of the prostate can constrict the urethra so that urinating becomes slow and painful.
Prostatic secretions vary among species. They are generally composed of simple sugars and are often slightly alkaline. In mammals, these secretions usually contain fructose. The prostatic secretions of usually contain N-Acetylglucosamine or glycogen instead of fructose.
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