Male Reproductive System and Semen Analysis

• The presentation covers the male reproductive system and semen analysis.

Male Reproductive System

• Primary sex organs: testis.
• Accessory sex organs include ducts, glands, and external genitalia.
• Ducts consist of the epididymis, vas deferens, ejaculatory duct, and urethra.
• Glands refers to the seminal vesicle, prostate, and bulbourethral gland.
• External genitalia: penis and scrotum

Functions of Testis

• During fetal development, testes are in the abdomen but descend into the scrotum by the seventh month of intrauterine development.
• Function: spermatogenesis (sperm production) and testosterone secretion.
• Spermatogonia undergo mitotic division beginning at puberty.
• Spermatogenesis occurs in the seminiferous tubules.
• LH acts on the Leydig cells to stimulate testosterone secretion.

Sertoli Cells

• FSH acts on Sertoli cells to stimulate spermatogenesis.
• Secrete luminal fluid, including androgen-binding protein.
• Secrete the protein hormone inhibin, which inhibits FSH secretion.
• Secrete paracrine agents influence the function of Leydig cells.
• Phagocytize defective sperm.
• Secrete, during embryonic life, Müllerian inhibiting substance (MIS), which causes the primordial female duct system to regress.

Leydig Cells

• LH acts on the Leydig cells to stimulate testosterone secretion.
• Testosterone is required for initiation and maintenance of spermatogenesis.
• Testosterone decreases GnRH secretion via an action on the hypothalamus.
• Testosterone inhibits LH secretion via an action on the anterior pituitary.
• Testosterone induces differentiation of male accessory reproductive organs and maintains their function.
• Testosterone induces male secondary sex characteristics; opposes action of estrogen on breast growth.
• Testosterone stimulates protein anabolism, bone growth, and cessation of bone growth.
• Testosterone is required for sex drive and may enhance aggressive behavior.
• Testosterone stimulates erythropoietin secretion by the kidneys.

Epididymis Function

• The epididymis is responsible for maturation and storage of sperms.
• It secretes a fluid that is ejaculated along with the sperm, containing special essential nutrients.
• It transports sperms to the Vas deferens

Vas Deferens Function

• Transports sperm from the epididymis to the ejaculatory duct.

Seminal Vesicles

• Secrete a mucoid material containing fructose, citric acid, nutrient substances, prostaglandins, and fibrinogen.
• Fructose and other substances in the seminal fluid are of considerable nutrient value.

Prostate Gland

• Secretes a thin, milky fluid containing calcium, citrate, phosphate ions, a clotting enzyme, and a profibrinolysin.
• This slightly alkaline prostatic fluid helps neutralize the acidity of secretions of seminal vesicles and the vagina.

Bulbourethral Glands

• Secrete mucus for lubrication and semen consistency.

Hormonal Control Summary

• GnRH, LH, FSH, Testosterone and Inhibin all contricute to male hormonal control.

Infertility

• Infertility is defined as the inability to conceive after one year of regular sexual intercourse without contraception.
• Types: Primary, Secondary
• Causes: Male infertility, Female infertility, Unexplained infertility.
• Sterility is a permanent inability to conceive.

Male Infertility - Causes

Pre-testicular causes

• Hypothalamic causes like Kalman syndrome, tumors, or idiopathic conditions disrupt GnRH secretion.
• Pituitary causes, such as panhypopituitarism from tumors, infarction, or iatrogenic damage, disrupt LH and FSH secretions.
• Thyroid disorders: Both hypothyroidism and hyperthyroidism alter spermatogenesis.
• Hyperprolactinaemia can result in sexual and reproductive dysfunction.
• Chromic diseases like Diabetes mellitus can cause pre-testicular infertility.

Testicular Causes of Male Infertility

• Genetic/Chromosomal disorders: Klinefelter's syndrome leads to abnormal sperm production.
• Congenital disorders: Sertoli cell only syndrome.
• Varicocele: Enlarged veins increase testicular temperature, reducing sperm quality.
• Cryptorchidism: Undescended testes impair sperm production if uncorrected.
• Testicular trauma/iatrogenic damage impairs sperm production.
• Testicular infection: Mumps orchitis.
• Testicular cancer.
• Gonadotoxins: Medications, environmental toxins damage germ cells or disrupt Sertoli cell function.

Post-testicular causes

• Ductal causes: Congenital absence, congenital obstruction, or acquired obstruction of the ductal system.
• Anti-sperm antibodies and immotile cilia syndrome leads to post-testicular infertility.
• Inadequate sexual performance: erectile or ejaculatory disorders such as retrograde ejaculation contributes.

Semen Analysis

• Semen consists of fluid and sperm where the vas deferens contributes 10%, seminal vesicles 60%, the prostate gland 30%, and mucous glands provide small amounts.
• Semen analysis is used to evaluate sperm parameters for male fertility assessment.

Semen Sample Precautions

• Collect the sample after 2-7 days of abstinence.
• Analyze the sample 30 minutes - 6 hours after collection.

Semen Analysis Parameters (Physical/Macroscopic)

• Volume: Normal is ≥1.4 mL; Aspermia is the absence of semen; Hypospermia is < 1.4 mL.
• Color: Normal is grayish-white, Greenish indicates a genital tract infection, Red or brown indicates hematospermia
• Liquefaction Time: Normal semen liquefies within 15-30 minutes
• Prostatic secretions and proteolytic enzymes are responsible for liquefaction.
• Viscosity: Normal is not too thick or watery otherwise high viscosity may reduce sperm motility in infertility
• pH: Normal pH is 7.2 -7.8; pH changes may be caused by acute & chronic inflammation of the prostate or seminal vesicles.

Semen Analysis Parameters (Microscopic)

• Sperm Concentration: Normal is > 16 million/mL, Zero signifies azoospermia, < 16 million/mL describes oligozoospermia.
• Total Sperm Count: Normal is > 39 million of spermatozoa
• Motility: Total motility is ≥ 42% and Progressive motility is ≥ 30%; Asthenozoospermia is when Total motility < 42% and progressive motility <30%
• Morphology: Normal is ≥ 4% normal forms, Teratozoospermia is < 4% normal forms, Abnormalities can include head, tail, and midpiece abnormalities.
• Viability - This is the percentage of live sperms in the sample
• Live and dead sperms are differentiated using Eosin-Nigrosin (vital) stain, which stains dead sperms only
• Normal ≥ 54% live sperms
• All spermatozoa are dead and show vital stain which signifies a Necrozoospermia condition. Sperm agglutination: is the tendency of motile sperms to form clumps.
• Types: consist of head to head, head to tail or tail to tail agglutination. Significant sperm agglutination: agglutination of > 10% of sperms, is due to infection or immunological factors (autoantibodies).
• Cellular components other than sperms:
  • Leukocytes: normal is normally < 1 million/ml
  • Pyospermia- Presence of > 1 million WBCs per ml indicates infection or autoimmune disorders
  • RBCs: normally absent
  • Hematospermia: Presence of red cells can be caused by infection and inflammation, trauma or iatrogenic damage, blood vessel abnormalities, or coagulation disorders.
• There should be a few Germinal and Epithelial cells in the sample, any more indicates issues.