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Understanding the Male Reproductive System: Sperm Production and Function

This detailed guide explores the process of spermatogenesis, from meiosis to the formation of sperm cells in the male reproductive system. It covers the structure of sperm cells, their journey through the male reproductive tract, and the role of hormones in regulating spermatogenesis.

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Understanding the Male Reproductive System: Sperm Production and Function

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  1. REPRODUCTIVE SYSTEM

  2. FUNCTION ?

  3. MEIOSIS http://missmsoledad.files.wordpress.com/2008/06/gametogenesis.jpg

  4. http://www.stanford.edu/group/Urchin/GIFS/meiosis1.gif

  5. DIFFERENCE BETWEEN FORMATION OF SPERM AND EGG ?

  6. PROPHASE I • SYNAPSIS: HOMOLOGOUS CHROMOSOMES PAIR UP AND INTERTWINE: FORMS TETRADS • CROSS OVER COMMON

  7. ANAPHASE I • HOMOLOGOUS CHROMOSOME PAIRS SEPARATE

  8. TELOPHASE I • SAME AS MITOSIS WITH REPLICATED PAIRS

  9. SECOND MEITOTIC DIVISION • PROPHASE II: SAME AS MITOSIS • ANAPHASE II: CENTROMERES SEPARATE RELEASING CHROMATIDS: NOW CHROMOSOMES • TELOPHASE II:

  10. MALE SYSTEM • PRODUCE/MAINTAIN SPERM CELLS • TRANSPORT TO FEMALE TRACT • SECRETE MALE SEX HORMONES

  11. TESTES • 1-2 MONTHS DROP FROM NEAR KIDNEYS TO SCROTUM ? • STIMULATED BY TESTOSTERONE • GUBERNACULUM • CRYPTORCHIDISM

  12. STRUCTURE • TUNICA ALBUGINEA • MEDIASTINUM TESTIS: CONNECTIVE TISSUE (SEPTA) DIVIDE TESTIS TO 250 LOBULES • LOBULE: 4 SEMINIFEROUS TUBULES UNITE TO RETE TESTIS IN MEDIASTINUM TO EPIDIDYMIS TO DUCTUS DEFERENS • SEMINIFEROUS TUBULES: SPECIALIZED STRATIFIED EPITHELIUM • SPERMATOGENIC CELLS: ? • INTERSTITIAL CELLS: CELLS OF LEYDIG: MALE SEX HORMONES

  13. SUSTENACULAR CELLS: SERTOLI CELLS: COLUMNAR; SUPPORT, NOURISH, REGULATE SPERMATAOGENIC CELLS aboutcancer.com

  14. SPERMATOGENESIS • MALE EMBRYO: HORMONES ACTIVATE SPERMATOGONIA: MITOSIS FORMS: • A CELLS (SAME) • B CELLS: PRIMARY SPERMATOCYTE • SPERMATOGENESIS WAITS TILL PUBERTY • MORE TESTOSTERONE: NEW MITOSIS; MEIOSIS  2 SECONDARY SPERMATOCYTES  SPERMATIDS HOW MANY? • DURING SPERMATOGENESIS CELLS MOVE TOWARDS LUMEN • BLOOD-TESTIS BARRIER: TIGHT JUNCTIONS OF SUSTENACULAR CELLS WHY? • SPERMATOGENSIS OCCURS CONTINUOUSLY

  15. SPERM CELLS  LUMEN  RETE TESTIS  EPIDIDYMUS: COLLECT/MATURE http://www.bing.com/images/search?q=sperm+cell&view

  16. SPERM CELL STRUCTURE • 0.06 mm • ACROMOSOME: ENZYMES TO ENTER EGG • HYALURONIDASE • MIDPIECE: MITOCHONDRIA ? • TAIL: FLAGELLUM: MICROTUBULES

  17. EPIDIDYMIDES • 6 METERS LONG • PSEUDOSTRATIFIEDCOLUMNAR, NONMOTILE CILIA SECRETE FLUID WITH GLYCOGEN FOR ? • PERISTALTSIS MOVES SPERM THROUGH AS MATURE

  18. DUCTUS DEFERENTIA • VASA DEFERENTIA/ VAS DEFERENS • 45 cm • PSEUDOSTRATIFIED COLUMNAR EPITHELIUM • THROUGH INGUINAL CANAL • END: DILATES TO AMPULLA • JOINS SEMINAL VESSICLE DUCT TO EJACULATORY DUCT TO PROSTATE GLAND TO URETHRA

  19. SEMINAL VESICLES • CONVOLUTED SAC, 5 cm • GLANDULAR TISSUE LINING: SECRETES SLIGHTLY ALKALINE FLUID WITH FRUCTOSE AND PROSTAGLANDINS • PROTECT SPERM AS IT TRAVELS • ENERGY • STIMULATE CONTRACTIONS OF FEMALE TRACT ?

  20. http://www.google.com/imgres?imgurl=http://rpmedia.ask.com/

  21. PROSTATE GLAND • 4 x 3 cm • BRANCHED TUBULAR GLANDS SEPARATED BY CONNECTIVE TISSUE SEPTA AND SMOOTH MUSCLE SECRETE INTO URETHRA • THIN, MILKY FLUID • ALKALINE VS. METABOLIC WASTE OF SPERM & FEMALE TRACT • HELPS MOBILIZE SPERM SMOOTH MUSCLE CONTRACTS FOR SECRETION WHEN SEMEN ENTERS

  22. BULBOURETHRAL GLANDS/ COWPER’S GLANDS • 1 cm • URETHRA BELOW PROSTRATE • TUBES OF GLANDULAR EPITHELIAL TISSUE • SECRETES MUCUS LIKE FLUID WHEN STIMULATION OCCURS FOR SOME LUBRICATION

  23. nursingcrib.com

  24. SEMEN • 2-5 mm • 120 MILLION SPERM PER mm • SPERM CELLS; FLUID FROM SEMINAL VESSICLES, PROSTATE GLAND AND BULBOURETHRAL GLAND • ALKALINE, PROSTAGLANDINS AND NUTRIENTS • CAPACITATION • LAST WEEKS IN MALE, CAN ONLY FERTILIZE FOR 1-2 DAYS

  25. EXTERNAL REPRODUCTIVE ORGANS • SCROTUM: • SUBCUTANEOUS MEMBRANE OF SMOOTH MUSCLE, NO FAT ? • 3º COOLER • MEDIAL SEPTUM DIVIDES IN TWO

  26. PENIS • BODY: ERECTILE TISSUE: PAIR OF COPORA CAVERNOSA AND CORPUS SPONGIOSUM • TUNICA ALBUGINEA GLANS: EXTERNAL URETHRAL ORIFICE • FORESKIN: PREPUCE

  27. PARASYMPATHETIC NS RELEASES VASODILATOR N ITRIC ACID • DILATES ARTERIES • THIS CONSTRICTS VEINS ? • (BLOOD ENTERS AND PRESSURE BUILDS) • SYMPATHETIC NS CONTROLS EMISSION (PERISTALSIS) AND EJACULATION ERECTILE TISSUE STIMULATED, SKELETAL MUSCLE CONTRACTS • BULBOURETHRAL FLUID FIRST, PROSTATE, SPERM, THEN SEMINAL VESSICLES

  28. HORMONAL CONTROL • HYPOTHALAMUS  GnRH  GONADOTROPINS: LH/FSH • LH (ICSH IN MALES) : STIMUATES DEVELOPMENT OF INTERSTITIAL CELLS • FSH STIMULATES SUSTENACULAR CELLS • FSH AND TESTOSTERONE SPERMATOGENESIS • SUSTENACULAR CELLS PRODUCE INHIBIN PREVENTS OVERPRODUCTION OF FSH

  29. MALE SEX HORMONES • ANDROGENS • MOSTLY BY INTERSTITIAL CELLS; SOME ? • TESTOSTERONE: STEROID HORMONE; CARRIED BY PLASMA PROTEINS TO RECEPTOR • IN PROSTATE, SEMINAL VESSICLES: CHANGED TO DIHYDROTESTOSTERONE TO FUNCTION • EXCESS CHANGED BY LIVER AND EXCRETED • PRODUCED AROUND BIRTH AND AT PUBERTY

  30. TESTOSTERONE ACTION • 8 WEEK EMBRYO: • FORMATION OF MALE GLANDS; TESTICULAR DECENSION LATER • PUBERTY: • MALE GLANDS GROW AND DEVELOP • SECONDARY SEXUAL CHARACTERISTICS: • BODY HAIR; ADAM’S APPLE; THICKENING OF SKIN; MUSCULAR GROWTH: SHOULDERS AND WAIST; BONES THICKEN/STRENGTHEN; INCREASED METABOLISM; RELEASE OF ERYTHROPOIETIN;

  31. REGULATION OF HORMONES • HYPOTHALAMUS RELEASES GnRH TO ANTERIOR PITUITARY TO RELEASE LH TO INTERSTITIAL CELLS TO RELEASE TESTOSTERONE • NEGATIVE FEEDBACK • MALE CLIMATERIC: TESTOSTERONE DECREASES

  32. FEMALE SYSTEM • FOR PRODUCTION AND MATURATION OF EGG • TRANSPORT FOR FERTILIZATION • ENVIRONMENT FOR EMBRYONIC DEVELOPMENT • BIRTH • FEMALE SEX HORMONES

  33. PRIMARY SEX ORGANS: OVARIES • 3.5 x 2 x 1 cm • HELD BY LIGAMENTS: • BROAD LIGAMENT; SUSPENSORY LIGAMENT AND OVARIAN LIGAMENT • DESCEND TO PELVIC BRIM • MEDULLA AND CORTEX • MEDULLA: LOOSE CONNECTIVE TISSUE, BLOOD, NERVES, LYMPH, • CORTEX: OVARIAN FOLLICLES • TUNICA ALBUGINEA

  34. OOGENESIS • EMBRYO: HAS ALL EGGS, MITOSIS: MORE OOGONIA  PRIMARY OOCYTES • PRIMARY OOCYTE COVERED BY FLATTENED EPITHELIAL CELLS= FOLLICULAR CELLS  PRIMORDIAL FOLLICLE; RESTS TILL PUBERTY • EMBRYO: SEVERAL MILLION EGGS  BIRTH: 1 MILLION  PUBERTY: 400,000  ~400 RELEASED  A FEW FERTILIZED

  35. PUBERTY: A FEW STIMULATED TO GO THROUGH MEIOSIS • UNEVEN CYTOPLASMIC DIVISION = POLAR BODIES • IF FERTILIZED, SECONDARY OOCYTE DIVIDES TO FORM LAST POLAR BODY • PUBERTY: INCREASED PRODUCTION OF FSH  OVARIES ENLARGE • FSH STIMULATES SOME (UP TO 20) PRIMORDIAL OOCYTES TO MATURE, FOLLICULAR CELLS DIVIDE = GRANULOSA CELLS: STRATIFIED EPITHELIUM, ZONA PELLUCIDA (GLYCOPROTINE LAYER) FORMS  PRIMARY FOLLICLE

  36. OVARIES DEVELOP: • INNER VASCULAR LAYER: THECA INTERNA: STEROID SECRETING CELLS • OUTER FIBROUS LAYER: THECA EXTERNA: CONNECTIVE TSSUE • FOLLICULAR CELLS PROLIFERATE: SECONDARY FOLLICLE • 1 WEEK: DOMINANT FOLLICLE FORMS MATURES IN 10-14 DAYS TO GRAAFIAN FOLLICLE • SECONDARY OOCYTE DEVELOPS WITH THICK ZONA PELLUCIDA AND CORONA RADIATA OF FOLLICLE WHICH SUPPLIES NUTRIENTS TO OOCYTE

  37. OVULATION: STIMULATED BY LH: CAUSES SWELLING & RUPTURE OF FOLLICLE • PICKED UP BY UTERINE TUBE: MUST BE FERTILIZED SHORTLY http://www.biog1105-1106.org/demos/105/unit8/media/ovary-schematic.jpg

  38. INTERNAL ACCESSORY ORGANS • UTERINE TUBES: • BROAD LIGAMENT • 10 cm x .7 cm • INFUNDIBULUM WITH FIMBRIAE http://upload.wikimedia.org/wikipedia/commons/d/d4/Gray589.png

  39. UTERUS • 7 x 5 cm x 2.5 cm • BROAD LIGAMENT COVERS • ROUND LIGAMENT TO PELVIC WALL • BODY • FUNDUS • CERVIX • CERVICAL ORIFICE • OSTIUM UTERI www.becomehealthynow.com/images/organs/reproduction/uterus_adnexa_bh.jpg

  40. ENDOMETRIUM • MUCOSAL, COLUMNAR EPITHEILIUM, TUBULAR GLANDS • MYOMETRIUM • SMOOTH MUSCLE: LONGITUDINAL, CIRCULAR, SPIRAL • PERIMETRIUM

  41. http://www.netterimages.com/

  42. VAGINA • 9 cm • FIBROMUSCULAR TUBE • ALLOWS SPERM IN/ BABY OUT • SURROUNDS CERVIX • VAGINAL ORIFICE: HYMEN • LAYERS • MUCOSAL: STRATIFIED SQUAMOUS, VAGINAL RUGAE, NO MUCOUS GLANDS • MUSCULAR: SMOOTH, LONGITUDINAL AND CIRCULAR; THIN STRIATED AT MOUTH ALSO BULBOSPONGIOSUS: CLOSED • FIBROUS: DENSE CONNECTIVE TISSUE, ELASTIC FIBERS, CONNECTIONS

  43. EXTERNAL ORGANS • LABIA MAJORA • ENCLOSE PROTECT REST • SKIN, ADIPOSE TISSUE, SMOOTH MUSCLE • HAIR, SWEAT GLANDS • COVERS VAGINAL OPENINGS • LABIA MINORA • FLATTENED LONGITUDINAL FOLDS INSIDE • CONNECTIVE TISSUE, BLOOD VESSELS • STRATIFIED SQUAMOUS

  44. CLITORIS • 2cm, 0.5 cm • 2 COLUMNS OF COPORA CAVERNOSA • SENSORY NERVE FIBERS

  45. VESTIBULE • SPACE WITHIN LABIA MINORA • VESTIBULAR GLANDS/BARTHOLIN’S GLANDS • VESTIBULAR BULBS: VASCULAR ERECTILE TISSUE

  46. CONTROL OF ORGASM • SEXUAL STIMULATION  PARASYMPATHETIC NS  VASODILATOR NITRIC OXIDE  ERECTION • STIMULATES VESTIBULAR GLANDS TO RELEASE MUCUS • CLITORAL STIMULATION  ORGASM  REFLEXES IN SACRAL AND LUMBAR SPINAL CORD  CONTRACTION OF UTERINE TUBES AND UTERUS ?

  47. HORMONAL CONTROL • ~10 YEARS: HYPOTHALAMUS  GnRH  ANTERIOR PITUITARY  FSH & LH  • OVARIES, ADRENAL CORTEX, PLACENTA RELEASE HORMONES • ESTROGEN • ESTRADIOL MOSTLY, ESTRONE, ESTRIOL • PROGESTERONE • PUBERTY: OVARIES RELEASE ESTROGEN: • ENLARGEMENT OF OVARIES AND OTHER ORGANS

  48. SECONDARY SEXUAL CHARACTERISTICS • DEVELOPMENT OF BREASTS AND MAMMARY GLANDS • MORE ADIPOSE TISSUE • INCREASES VASCULARIZATION OF SKIN PROGESTERONE: FROM OVARIES: CHANGES IN ENDOMETRIUM LINING, MAMMARY GLANDS, RELEASE OF GONADOTROPINS ANDROGEN: FROM ADRENAL CORTEX: MORE HAIR, DEVELOPMENT OF SKELETON

  49. REPRODUCTIVE CYCLE • FIRST: MENARCHE • HYPOTHALAMUS  GnRH  ANTERIOR PITUITARY  FSH & LH • FSH: MATURATION OF FOLLICLE; GRANULOSA CELLS  ESTROGEN AND SOME PROGESTERONE • LH  OVARIAN CELLS  PRECURSOR MOLECULES  ESTROGEN • INCREASING ESTROGEN LEVEL  PROLIFERATIVE STAGE: ENDOMETRIUM THICKENS AS FOLLICLE MATURES

  50. DAY 14: ANTERIOR PITUITARY RELEASES LH  OVULATION • OLD FOLLICLE/THECA INTERNA  CORPUS LUTEUM: GLANDULAR  PROGESTERONE  DEVELOPS ENDOMETRIUM MORE & UTERINE GLANDS TO SECRETE GLYCOGEN AND LIPIDS: SECRETORY PHASE ?? • HIGH ESTROGEN AND PROGESTERONE INHIBIT FSH & LH NO MORE FOLLICLE STIMULATION • IF NOT FERTILIZED: CORPUS LUTEUM  CORPUS ALBICANS: ESTROGEN AND PROGESTERONE DECREASE

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