12 Male Reproductive Medicine
Male Reproductive Medicine The medical specialty that studies the anatomy and physiology of the male genitourinary system and uses diagnostic tests, medical and surgical procedures, and drugs to treat male reproductive diseases.
Anatomy and Physiology External Genitalia Scrotum Testes Epididymides Penis Urethra
Anatomy and Physiology (cont’d) • Internal Genitalia • Vas deferens • Seminal vesicles • Ejaculatory ducts • Prostate gland • Bulbourethral glands
Anatomy and Physiology (cont’d) • The male genitourinary system shares the urethra with the urinary system and is also known as the urogenital system.
Male Reproductive System Animation Click on the screenshot to view an animation of the male reproductive system. The animation may require a few seconds before playing. Back to Directory
Anatomy of the Male Genitourinary System Scrotum Soft pouch of skin behind the penis and in front of the legs Few degrees cooler than the core body temperature Muscles in wall of the scrotum contract or relax to move the scrotum closer to, or farther away from, the body to adjust to temperature changes
Anatomy of the Male Genitourinary System (cont’d) Scrotum (cont’d) Perineum is the area between the anus and the scrotum Testis The scrotum contains the testes or testicles. Egg-shaped glands about 2 inches in length. Testes are the gonads, or sex glands.
Testis (cont’d) Function as part of the male genitourinary system and the endocrine system Contains the seminiferous tubules that produce spermatozoa, or sperm Acts as a gland and secretes the hormone testosterone Anatomy of the Male Genitourinary System (cont’d)
Epididymis A long, coiled tube (over 20 feet) that is attached to the outer wall of each testis. Within the epididymis, the head of each spermatozoon is given a cap-like layer of enzymes that helps it penetrate and fertilize the ovum of the female. Destroys defective spermatozoa Anatomy of the Male Genitourinary System (cont’d)
Vas Deferens, Seminal Vesicles, and Ejaculatory Duct The vas deferens is a long duct that receives spermatozoa from the epididymis. Spermatozoa can be stored in the vas deferens for several months in an inactive state. The vas deferens goes behind the urinary bladder, where it merges with a seminal vesicle. Anatomy of the Male Genitourinary System (cont’d)
Anatomy of the Male Genitourinary System (cont’d) • Vas Deferens, Seminal Vesicles, and Ejaculatory Duct (cont’d) • The seminal vesicles produce seminal fluid, which makes up most of the volume of semen. • The ejaculatory duct is a large collecting duct that holds spermatozoa and seminal fluid. • The ejaculatory duct enters the prostate gland, then joins the urethra within the prostate gland.
Prostate Gland A round gland at the base of the bladder that produces prostatic fluid. Prostatic fluid contains an antibiotic substance that kills bacteria and also contains acid phosphatase, an enzyme that breaks the deposit of semen apart and releases the spermatozoa in the woman’s vagina. Anatomy of the Male Genitourinary System (cont’d)
Bulbourethral Glands Small, bulblike glands about the size of peas, located on either side of the urethra just below the prostate gland Produce thick mucus that makes up some of the volume of the semen and neutralizes the acidity of any urine remaining in the urethra at the time of ejaculation Anatomy of the Male Genitourinary System (cont’d)
Penis Functions as an organ of the male genitourinary system and the urinary system In uncircumcised males, the urethral meatus is covered by the prepuce, or foreskin, of the penis. Three columns of erectile tissue fill with blood during sexual arousal, causing the penis to become firm and erect. Anatomy of the Male Genitourinary System (cont’d)
Physiology of Spermatogenesis, Sexual Maturity, and Ejaculation Spermatogenesis At the onset of puberty, the anterior pituitary gland in the brain begins to secrete follicle-stimulating hormone (FSH) and luteinizing hormone (LH) to stimulate the testes. FSH stimulates spermatocytes in the testes to begin dividing. LH stimulates the interstitial cells to begin to secrete testosterone.
Physiology of Spermatogenesis, Sexual Maturity, and Ejaculation (cont’d) Sexual Maturity Testosterone causes the male sexual characteristics to develop: enlargement of the external genitalia; development of large muscles; deepening of the voice; growth of body hair on the face, chest axillae, and genital areas; development of the sexual drive
Physiology of Spermatogenesis, Sexual Maturity, and Ejaculation (cont’d) Ejaculation Thoughts or sensations initiate sexual arousal. Smooth muscle relaxes in the wall of arteries in the penis, and vasodilation increases blood flow within the penis. The corpora cavernosa and the corpus spongiosum distend with blood and produce an erection.
Ejaculation (cont’d) Muscles at the base of the penis contract Spermatozoa mix with seminal fluid, move into the urethra, and are mixed with mucus from the bulbourethral glands. A series of contractions cause semen to be expelled from the penis through the urethral meatus. Physiology of Spermatogenesis, Sexual Maturity, and Ejaculation (cont’d)
Diseases and Conditions Testis and Epididymis Cryptorchidism Epididymitis Infertility
Diseases and Conditions (cont’d) Testis and Epididymis (cont’d) Oligospermia Orchitis Testicular cancer Varicocele
Figure 12-6 Oligospermia Custom Medical Stock Photo, Inc.
Diseases and Conditions (cont’d) Prostate Gland Benign prostatic hypertrophy (BPH) Cancer of the prostate gland Prostatitis
Diseases and Conditions (cont’d) Penis Balanitis Chordee Dyspareunia
Diseases and Conditions (cont’d) Penis (cont’d) Erectile dysfunction (ED) Phimosis Premature ejaculation
Diseases and Conditions (cont’d) Penis Priapism Sexually transmitted disease (STD)
Diseases and Conditions (cont’d) Male Breast Gynecomastia
Laboratory and Diagnostic Procedures Blood Tests Acid phosphatase Hormone testing Prostate-specific antigen (PSA) Syphilis testing
Laboratory and Diagnostic Procedures (cont’d) Semen Tests Acid phosphatase DNA analysis Semen analysis
Figure 12-8 Spermatozoa John Walsh/Photo Researchers, Inc.
Laboratory and Diagnostic Procedures (cont’d) Radiologic Tests ProstaScint scan Ultrasonography
Medical and Surgical Procedures Medical Procedures Digital rectal examination (DRE) Newborn genital examination Testicular self-examination (TSE)
Medical and Surgical Procedures (cont’d) Surgical Procedures (cont’d) Biopsy Circumcision Orchiectomy Orchiopexy
Medical and Surgical Procedures (cont’d) Surgical Procedures (cont’d) Penile implant Prostatectomy Transurethral resection of the prostate (TURP) Vasectomy
Figure 12-11 Laser for prostate surgery Custom Medical Stock Photo, Inc.
Drug Categories These categories of drugs are used to treat male genitourinary Diseases and Conditions: Androgen drugs Antiviral drugs Drugs for benign prostatic hypertrophy Drugs for erectile dysfunction