Male reproductive system

• What is the anatomy of the male reproductive system?


  Gonads (testis) , spermatic ducts , sex accessory glands , copulatory organ (penis)
• Why are the testis not inside the abdomen?


  Because if they were , it would be warmer and so sperm will not mature well leading to infertility
• What is the cremasteric muscle?


  Sperm cord + scrotum
• What is the dartos muscle?


  smooth muscle of the scrotum
• What are the characteristics of the testicular vascular supply?

  Venous , pampiniform plexus (network of small veins) (help to lower temperature)
• What is cryptorchidism?


  undescended testes
• What is varicocele?


  dilated varicose veins (impairs venous flow) , affects mainly left testicle
• What is testicular torsion?


  Testis inadequately affixed to the scrotum , spermatic cord rotation , if occurs for more than 6h then there is irreversible ischemia and necrosis
• How does sperm form?


  Forms in testis (spermatogenesis). Primordial germ cells differentiate into spermatogonia (fetal and infant testis contains spermatogonia). In puberty increased testosterone starts meiosis leading to sperm formation
• What are the testicular layers?

  head of epididymis , tunica albuginea , tunica vaginalis , body of epididymis and rete testis
• What are the characteristics of seminiferous tubules?


  Site of spermatogenesis
• What are the characteristics of the seminiferous epithelium?


  Composed of germ and steroli cells and other sperm cells in various development stages
• What is the process of spermatogenesis?

  Spermatogonia will differentiate into primary spermatocyte which will undergo meiosis and produce a secondary spermatocyte. The secondary spermatocyte will undergo meiosis again to produce spermatid which will differentiate into sperm (4 cells)
• How long do the meiotic divisions occur in spermatogenesis?


  First meiotic division takes 22-23 days (basal part)

  
  

  Second division takes 1 day (apical part)
• What is the morphology of a sertoli cell?


  irregular shape , elongated irregular nucleus with nucleolus , tight junctions
• What is the function of the sertoli cell?


  Nurtures germ cells , provides androgens , physical scaffold , immune system protection
• What is the function of the leydig cell?


  produce testosterone
• What is the morphology of leydig cells?

  Polyedric , round nuclei
• What is the role of testosterone?

  Male reproductive system development , spermatogenesis , maintenance of reproductive system , secondary sex characteristics
• What is AIS (androgen insensitivity syndrome) ?


  mutations in androgen receptor and during development cells do not respond to androgens. Female appearance , may lack ovaries and uterus or menstruation , frequently sterile
• How do androgens work in androgen dependent cells?


  In 6th week we have undifferentiated developing gonads. When SRY gene (sex determining region) is activated testis is developed with androgen receptors
• What occurs to AIS androgen receptors?


  In week 7 there is a lack of androgen receptors and therefore there is a lack of development of mullerian or wolffian ducts. The body thinks there is no testosterone and so androgens increase leading to no effect and so the testosterone aromatase leading to estrogens which is what causes feminine appearance
• How are hormones regulated?


  Hypothalamus releases gonadotropin releasing hormone which stimulates hypophysis which releases FSH which stimulates setoli cells (mature germ cells) which is absorbed by ABP. Hypophysis also releases LH which stimulate leydig cells which releases testosterone which stimulate sertoli cell
• What are the characteristics of the epididymis?


  provides motility to sperm , glycoproteins (maturation) (fertilization ability) and sperm storage (tail) , pseudostratified columnar epithelium with sterocilia
• What are the characteristics of the deferent duct?

  Carries sperm from prostate to epididymis
• What are the characteristics of the seminal vesicles?


  Secretion: seminal plasma; jelly and sticky appearance of semen

  
  

  Epithelium:pseudostratified columnar , secretion of nutrients , bicarbonate , prostaglandins
• What are the characteristics of the prostate?

  secretion: Prostate specific antigen (PSA( , prostaglandins , citric acid (antioxidant)
• What is BPH (benign prostatic hyperplasia)?


  swelling of prostate
• What are the characteristics of bulbourethral glands?

  Secretion: Pre-ejaculate , mucoproteins (lubrication) , basic ph (neutralize urine)
• What are the characteristics of the penis?


  Three columns of erectile tissue , two dorsal (Corpora cavernosa) , one ventral (corpus spongiosum)
• What is the mechanism of viagra?


  Parasympathetic NS releases nitric oxide in endothelial cell which diffuses to smooth muscle cell which triggers GTP to cGMP conversion leading to vasodilation and erection