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Male Reproductive System

Outline

A. Structure and Function

1. spermatic cord- consists of arteries, veins, lymphatics, nerves, cremaster muscle and vas deferens (ductus deferens)

2.. testes- responsible for both testosterone and sperm production

                a. seminiferous tubules- site of sperm production

b. Cells of Leydig- testosterone production

c.develop in abdomen, descend into scrotal sac during 7 - 8th month of fetal development, inguinal canal closes almost completely before birth

3. epididymis- site of sperm maturation

4.seminal fluid- a thin milky alkaline fluid containing fructose, enzymes and calcium acid phophatase, composed of secretions from

    a. epididiymis

    b. seminal vesicles

    c. prostate

    d. bulbourethral (Cowper’s glands)

5. foreskin- covers glans penis, smegma = accumulation caused by oily glands in foreskin

6. actions of testosterone

    a. differentiation of male genital tract during fetal development

    b. development of primary and secondary sexual characteristics

    c. anabolic effects

B. Disorders of the Penis

a. Hypospadias (urethra terminates on ventral surface of penis) and epispadias (urethra terminates on dorsal surface of penis)

b. phimosis - foreskin to tight to be retracted over glans

c. priapism - nonsexual, prolonged, painful erection

d. Peyronie’s disease - fibrous growth on top of penile shaft,  cuasing bending

e. balanoposthitis (balanitis)- inflammation of glans penis

C. Disorders of Scrotum and Testes

a. cryptorchidism - undescended testes, one or both

b. hydrocele- collection of fluid within scrotal sac, between outer parietal layer and inner visceral layer of tunica vaginales

d. spermatocele- cyst containing sperm which forms at end of  epididymis

e. testicular torsion

1. extravaginal - mostly in neonates, testicle rotates around spermatic cord at or above tunica vaginales

2. intravaginal- mostly occurs between 8 - 18 yrs of age, testicle rotates around distal spermatic cord , true surgical emergency

f. variocele- varicosities of veins supplying testes

D. Inflammations of Scrotum and Testes

                    a. tinea cruris- fungal infection

                    b. epididymitis

                    c. orchitis

                            1. possible complication in those > 10 yrs of age = mumps orchitis

E. Testicular Cancer

                a. germ cell tumors (95%)

                    1. seminoma (40%)

                    2. nonseminoma

                b. nongerminal tumors (5%)

F. Disorders of Prostate

a. prostatitis (acute or chronic)

c. prostate cancer

Discussion  

Males produce estrogen, as well as testosterone. In males, estrogen is produced by the adrenal glands (which also produce testosterone.). Likewise, females produce testosterone, as well as estrogen (again, the adrenal gland produces both estrogen and testosterone). The ratios of these two hormones, of course, differs significantly between males and females, with males having high levels of testosterone, low levels of estrogen and vice versa in females. Occasionally, levels of estrogen in males may become elevated. For example, a male with cirrhosis of the liver is unable to break estrogen down and, therefore, it builds up in the bloodstream. Elevated levels of estrogen in a male causes gynecomastia,For sperm to mature properly they need an optimal temperature which is about 2- 3 degrees less then body temperature. The cremaster muscle can move the scrotum closer to or further away from the abdomen to help maintain optimal body temperature. In the case of a hydrocele, the retained water can act as insulation (much like a thermos bottle) and can interfere with proper sperm maturation, resulting in infertility. Secretions from the accessory sex glands (prostate, seminal vesicles, Cowpers) bring the pH of semen into a range of 6.0 - 6.5. This alkaline pH helps to protect the sperm by buffering the extremely acidic pH of the vagina.

Clinically  

Although rare, testicular cancer, nonetheless, accounts for 1% of all male cancers and it is the most common cancer in men between the ages of 15 - 35. The incidence of testicular cancer is 35 times higher in males with cryptoid testis. The administration of exogenous estrogen to the mother during pregnancy has also been associated with an increased risk . Because testicular cancer is treatable if caught in the early stages, the American Cancer society recommends that all young adult males perform a testicular self exam at least once a month.Prostatic cancer is the most common male cancer in the United States. On physical exam the prostate is nodular and fixed (compared to BPH, where on physical exam the prostate is smooth and rubbery). Diagnosis of prostate cancer is confirmed by biopsy. Prostate specific antigen (PSA) is often used as a screening test. Normally, PSA is less than 4.0 ng/ml. It increases in concentration with advancing prostate cancer. However, it is also elevated in 25% of patients with BPH. Prostate manipulation, prior to collection of the blood sample (as would occur in digital rectal exam) can elevate PSA.. PSA testing is of controversial value in large screening programs. Nonetheless, it has been recommended by the American Cancer Society for use in conjunction with a digital rectal exam in screening for all men over 50 years of age.Metastatic prostate cancer is typically treated by antiandrogen therapy (the idea being that prostate cancer cells feed on androgen, by depriving them of androgen, you can "starve" them to death, so to speak). This can take one of four forms: a. estrogen therapy (side effect is often gynecomastia), b. orhiectomy ,c. blocking testosterone production through treatment with leutinizing hormone releasing hormone analogue that blocks release of LH from pituitary (e.g. leuprolide) or 4. Nonsteroidal antiandrogen such as flutamide (this blocks uptake of androgens in the target tissues)