Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Spermatogenesis bds


Published on

Published in: Health & Medicine, Technology
  • Be the first to comment

Spermatogenesis bds

  1. 2. testis <ul><li>Normal spermatogenesis can occur only if the testes are at a temperature lower than that of the abdominal cavity. </li></ul><ul><li>When they are located in the scrotum, they are at a temperature about 3°C lower than the abdominal temperature. </li></ul>
  2. 3. epididymis <ul><li>The long length of the duct of the epididymis provides storage space for the spermatozoa and allows them to mature. </li></ul><ul><li>A main function of the epididymis is the absorption of fluid. </li></ul><ul><li>Another function may be the addition of substances to the seminal fluid to nourish the maturing sperm </li></ul>
  3. 4. Vas deferens <ul><li>conveys mature sperm from the epididymis to the ejaculatory duct and the urethra. </li></ul>
  4. 5. Seminal vesicle <ul><li>The function of the seminal vesicles is to produce a secretion that is added to the seminal fluid. The secretions nourish the spermatozoa. </li></ul><ul><li>During ejaculation the seminal vesicles contract and expel their contents into the ejaculatory ducts, thus washing the spermatozoa out of the urethra. </li></ul>
  5. 7. Ejaculatory duct <ul><li>their function is to drain the seminal fluid into the prostatic urethra. </li></ul>
  6. 8. prostate <ul><li>The prostate produces a thin, milky fluid containing citric acid and acid phosphatase that is added to the seminal fluid at the time of ejaculation </li></ul><ul><li>The prostatic secretion is alkaline and helps neutralize the acidity in the vagina. </li></ul>
  7. 9. Structure of testis
  8. 12. <ul><li>Gametogenesis (gamete formation) is the process of formation and development of specialized generative cells, gametes . </li></ul>
  9. 13. <ul><li>Gamete maturation is called spermatogenesis in males and oogenesis in females. </li></ul>
  10. 15. SPERMATOGENESIS <ul><li>Spermatogenesis is the sequence of events by which spermatogonia are transformed into mature sperms . This maturation process begins at puberty. </li></ul>
  11. 17. <ul><li>Spermatogonia , which have been dormant in the seminiferous tubules of the testes since the fetal period, begin to increase in number at puberty. </li></ul><ul><li>After several mitotic divisions, the spermatogonia grow and undergo changes. </li></ul>
  12. 19. <ul><li>Sertoli cells lining the seminiferous tubules support and nurture the germ cells and may be involved in the regulation of spermatogenesis. </li></ul>
  13. 20. <ul><li>Spermatogonia are transformed into primary spermatocytes , the largest germ cells in the seminiferous tubules. </li></ul>
  14. 21. <ul><li>Each primary spermatocyte subsequently undergoes a reduction division-the first meiotic division-to form two haploid secondary spermatocytes , which are approximately half the size of primary spermatocytes. </li></ul>
  15. 23. <ul><li>Subsequently, the secondary spermatocytes undergo a second meiotic division to form four haploid spermatids, which are approximately half the size of secondary spermatocytes. </li></ul>
  16. 24. spermiogenesis <ul><li>The spermatids are gradually transformed into four mature sperm by a process known as spermiogenesis </li></ul>
  17. 27. <ul><li>The entire process of spermatogenesis, which includes spermiogenesis, takes approximately 2 months. </li></ul><ul><li>When spermiogenesis is complete, the sperms enter the lumina of the seminiferous tubules. </li></ul>
  18. 31. <ul><li>Sperms are transported passively from the seminiferous tubules to the epididymis , where they are stored and become functionally mature. </li></ul>
  19. 32. <ul><li>The epididymis is the elongated coiled duct along the posterior border of the testis . </li></ul><ul><li>It is continuous with the ductus deferens (vas deferens), which transports the sperms to the urethra. </li></ul>
  20. 33. <ul><li>Mature sperms are free-swimming, actively motile cells consisting of a head and a tail . </li></ul>
  21. 35. <ul><li>The head of the sperm forms most of the bulk of the sperm and contains the haploid nucleus. </li></ul><ul><li>The anterior two thirds of the nucleus is covered by the acrosome , a caplike saccular organelle containing several enzymes. </li></ul>
  22. 36. <ul><li>When released, these enzymes facilitate dispersion of the follicular cells of the corona radiata and sperm penetration of the zona pellucida during fertilization. </li></ul>
  23. 37. <ul><li>The neck of the sperm is the junction between the head and tail. </li></ul><ul><li>The tail of the sperm consists of three segments: middle piece, principal piece, and end piece </li></ul>
  24. 38. <ul><li>The tail provides the motility of the sperm that assists its transport to the site of fertilization. </li></ul><ul><li>The middle piece of the tail contains mitochondria, which provide the adenosine triphosphate necessary for activity. </li></ul>
  25. 39. Laboratory tests for male infertility <ul><li>Semen analysis </li></ul><ul><ul><li>Gold standard test for infertility </li></ul></ul><ul><ul><li>Components of semen </li></ul></ul><ul><ul><ul><li>Spermatozoa derive from the seminiferous tubules. </li></ul></ul></ul><ul><ul><ul><li>Coagulant derives from the seminal vesicles </li></ul></ul></ul><ul><ul><ul><li>Enzymes to liquefy semen derive from the prostate gland. </li></ul></ul></ul>
  26. 40. <ul><ul><li>Components evaluated in a standard semen analysis </li></ul></ul><ul><ul><ul><li>Volume </li></ul></ul></ul><ul><ul><ul><ul><li>Volume does not correlate with the number of sperm. </li></ul></ul></ul></ul><ul><ul><ul><li>Sperm count </li></ul></ul></ul><ul><ul><ul><ul><li>Normal is 20 to 150 million sperm/mL. </li></ul></ul></ul></ul><ul><ul><ul><li>Sperm morphology </li></ul></ul></ul><ul><ul><ul><ul><li>Morphology is very abnormal in reconnections of a vasectomy. </li></ul></ul></ul></ul><ul><ul><ul><li>Sperm motility </li></ul></ul></ul><ul><li>Serum gonadotropins, testosterone, prolactin </li></ul>