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The Reproductive System

The Reproductive System. Chapter 16. Intro to reproductive system. All other systems act continuously, but reproductive doesn’t come online time puberty Gonads – testes and ovaries, primary sex organs Gonads – produce gametes and secrete sex hormones Males – sperm Females - ova

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The Reproductive System

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  1. The Reproductive System Chapter 16

  2. Intro to reproductive system • All other systems act continuously, but reproductive doesn’t come online time puberty • Gonads – testes and ovaries, primary sex organs • Gonads – produce gametes and secrete sex hormones • Males – sperm • Females - ova • Accessory reproductive organs • Joint purpose of male and female reproductive system is to produce offspring

  3. Anatomy of Male • 1° organ are testes (gonads) • Exocrine function - sperm producing • Endocrine function - testosterone • Accessory structures are ducts or glands that deliver sperm to body exterior or female reproductive tract.

  4. Testes • Scrotum - skin • Tunica albuginea – fibrous connective tissues surrounds each tetis • Extends into testis and divides into lobules • 1-4 seminiferous tubules in each lobules • Sperm forming factories • Rete testis -> epididymis (first part of duct system) • In soft conn. Tissue surrounding seminiferous tubules are interstitial cells secrete testosterone Figure 16.1

  5. Duct SystemEpididymus • Highly coiled tube – about 20ft • Part of duct system • Storage site for immature sperm entering from testis • Sperm travel takes about 20 days, maturing, gain ability to swim • Ejaculation – walls contract to expel sperm into next part of duct system Figure 16.2b

  6. Duct SystemDuctus Deferens – vas deferens • Runs from testis over bladder • Enclosed by connective tissue sheath called spermatic cord with blood vessels and nerves • Empties into ejaculatory duct – passes through prostate to merge with urethra. • Ejaculation – smooth muscle in wall create peristaltic waves move sperm • Vasectomy – ties off vas deferens in scrotum • Sterile? • Testosterone? Figure 16.2a

  7. Duct SystemUrethra • Last part of duct system • 3 regions • Prostatic urethra – surrounded by prostate • Membranous urethra • Spongy (penile) urethra –length of penis • Carries both urine and sperm, but never at same time • Ejaculation – sperm enter prostatic urethra from ejaculation ducts, bladder sphincter constricts, no sperm in bladder, no urine in ejaculate

  8. Accessory GlandsSeminal Vesicles • Base of bladder • Produce 60% of seminal fluid, fluid of semen • Thick, yellow secretion rich in fructose, Vit C, prostaglandins and others – nourish and activate sperm as pass • Joins with vas deferens to form ejaculatory duct • Sperm and seminal fluid enter urethra together

  9. Accessory GlandsProstate • Sits under bladder, encircles upper urethra • Secretes milky fluid helps activate sperm • What happens when enlarged? • Prostate cancer 3rd most common cancer in men

  10. Accessory GlandsBulbourethral Glands • Secrete clear, thick mucus drains into penile urethra • 1st to pass down urethra when man excited • Cleanses urethra of acidic urine and lubricant during intercourse

  11. Semen • Milky white - sperm and gland secretions • Liquid – transport medium for nutrients and chemicals support sperm • Fructose provides most of energy • Alkaline 7.2-7.6 pH to counteract acidity of vagina 3.5-4 pH • Ejaculate is normally 2 to 5 ml, but 50-150 million sperm, acts a dilutant

  12. External Genitalia • Penis – delivers sperm into female reproductive tract • Shaft, glans penis, foreskin • Erectile tissue – fills with blood during excitement - erection • Scrotum – divided sac of skin outside of body, holds testes • Keeps temp at 5.4°F lower than body temp • In cold temp, scrotum shrinks up, SA reduced

  13. Anatomy of Female • More complicated than male – two functions, must produce ova, but also carry and protect fetus. • Ovaries 1° female reproductive organ • Exocrine function – ova • Endocrine function – estrogens and progesterone • Accessory Organs • Transport, nurture, serve needs of reproductive cells or fetus

  14. Ovaries • Ovarian follicles – sac like structures • Each contain immature egg called oocyte • Mature egg in mature follicle is Mature vesicular • Ovulation • Corpus luteum Figure 16.7 Figure 16.8b

  15. Duct SystemFallopian Tubes • Accepts oocyte • Site of fertilization • Supported by ligaments • Enters uterus • Little or no contact with ovary • Fimbriae create currents directing oocyte • Peristalsis and cilia move egg takes 3-4 days • Oocyte viable for 24 hours after ovulation Figure 16.8b

  16. Duct SystemUterus • In women never before pregnant size of pear • Gets very large during pregnancy • 3 layers • Endometrium – fertilized egg burrows in • Myometrium – smooth muscle, labor • perimetrium

  17. Duct System Vagina • Birth Canal • Menstrual flow • Female organ of copulation Figure 16.8a

  18. External Genitalia • Vulva • Mons pubis – fatty area covers pubic symphysis • Labia majora and minora – skin folds • Vestibule – enclosed in labia, contains external openings of urethra and vagina • Greater Vestibular Glands – secretion lubricates vagina during intercourse • Diamond area called perineum Figure 16.9

  19. Mammary Glands • Present in both sexes, usually only active in females • Estrogen at puberty stimulates growth • Function only after reproduction has occurred • Modified sweat glands that are part of skin Figure 16.13

  20. Result of Reproduction

  21. The End

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