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The reproductive system

The reproductive system. Chapter 19. The reproductive system intro. GONADS Reproductive organs that produce hormones and gametes GAMETES Reproductive cells. The male reproductive system overview. Testes Reproductive tract Accessory glands Semen Penis

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The reproductive system

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  1. The reproductive system Chapter 19

  2. The reproductive system intro GONADS Reproductive organs that produce hormones and gametes GAMETES Reproductive cells

  3. The male reproductive system overview • Testes • Reproductive tract • Accessory glands • Semen • Penis • Hormones and reproductive function

  4. The male reproductive system: testes TESTES is plural of testis, a single male gonad. • Produces male gametes called spermatozoa (singular: spermatozoon) or simply sperm. • Testes hang within the scrotum. • Cremaster muscle: contraction brings the testes closer to the body. • Helps regulate temperature of testes. • Dartos muscle: • Gives the scrotum a wrinkled appearance

  5. The male reproductive system: testes • Tunica albuginea: individually wrap around each testis. • Septa (general term for ‘wall’): Each testis is itself subdivided into lobules. • Interstitial cells in-between seminiferous tubules; secrete hormones. • Seminiferous tubules: sites of sperm production.

  6. The male reproductive system: testes Seminiferous tubules contain: • Spermatagonia: stem cells involved in spermatogenesis. • Sustentacularcells (Sertoli cells): sustain and promote spermatozoa development.

  7. SPERMATOGENESIS • Mitosis • Meiosis • Spermiogenesis • Sperm has: • head (with nucleus) • middle piece (contains mitochondria) • tail (flagellum)

  8. The male reproductive system: reproductivetract • Epidydimus (Gr. “Upon the testicle”): 7m-long tubule. • Ductus/vas deferens (Ltn. “Carrying-off duct/vessel”): meets up with the seminal vesicle at the ejaculatory duct. • Urethra: goes from bladder to the tip of the penis.

  9. The male reproductive system: accessoryglands • Seminal Vesicles: a convoluted tubular gland, producing approximately 60% of semen volume: • Fructose: to be metabolized by the spermatozoa • Prostaglandins: stimulates muscle contractions in both the male and female reproductive tracts. • Fibrinogen: forms a temporary clot within the vagina; slightly alkaline to neutralize pH in the prostate and vagina. When mixed with seminal vesicle excretions, stimulate sperm motility. • Prostate Gland: secretes fluid that makes up about 30% semen volume. • Bulbourethral Glands: secrete alkaline mucous, which has lubricating properties.

  10. The male reproductive system: semen • An ejaculation has 2-5mL of semen (or ejaculate) • 20-100 million sperm/mL

  11. The male reproductive system: penis • Most of the penis consists of 3 masses of erectile tissue. • 2 Corpora cavernosa(cavernous bodies) • 1 Corpusspongiosum(spongy body)

  12. The male reproductive system: hormones and reproductive function • GnRH: Gonadotropin-releasing hormone • FSH: Follicle-stimulating hormone • LH: Luteinizing hormone

  13. The female reproductive system overview • Ovaries • Uterine Tubes • Uterus • Vagina • External Genitalia • Mammary glands • Hormones and the female reproductive cycle

  14. THE FEMALE REPRODUCTIVE SYSTEM: OVARIES OVARIES: primary female sex organ Responsible for: • Producing gametes (ova) • Secretion of sex hormones (e.g. estrogens, progestins) and inhibin • Ovarian follicles are the site of oogenesis: ovum production • Occurs monthly as part of the ovarian cycle • Ovulation: an oocyte and the surrounding follicular walls of the corona radiata(circle) are expelled through the ruptured ovarian wall.

  15. THE FEMALE REPRODUCTIVE SYSTEM: UTERINE TUBES • Also: fallopian tube, oviduct, salpinges (plural of salpinx, Gr. For “trumpet”) • Infundibulum(funnel): leads to ampulla, then the isthmus to the uterine cavity. • Fimbriae: connect to the ovary

  16. THE FEMALE REPRODUCTIVE SYSTEM: THE UTERUS • Uterus: provides physical protection and nutritional support to the developing baby. • Body; top is the fundus • Cervix: “neck” • Internal/External orifice (os): upper and lower openings of the cervix. • Uterine cavity: open space of the uterus • Uterine wall: (-metrium: womb) • Inner endo-metrium • Muscular myo-metrium • Myometrial contractions: “cramps” • Superficial peri-metrium

  17. THE FEMALE REPRODUCTIVE SYSTEM: uterine cycle • Also known as menstrual cycle • 28 days long • Menses Phase (menstruation) • Destruction of functional zone of endometrium • 1-7 days • Proliferative phase • Repair and thickening of functional zone of endometrium • 7 days • Secretory phase • Endometrial glands are active and the uterus is prepared to accept an embryo • 14 days • In the lifelong development of a female: • Menarche: beginning of menstruation (men + arche “beginning”) • Menopause: end of menstruation (men + pause “stop”)

  18. THE FEMALE REPRODUCTIVE SYSTEM: OVARIAN cycle • Follicle: a (usually) spherical cavity where some other structure grows. • Ovarian follicles: specialized structures in the ovaries where oocytes grow and the first phase of meiosis and oogenesis occur. • 28 days long • Follicular phase: (First 14 days) follicles mature. By day 5, only 1 is ready to go. • Ovulation: (Halfway point) ovum is released from a follicle into the fimbriae. • Luteal phase: (Last 14 days) Empty follicle collapses, remaining cells multiply to make an endocrine structure known as the corpus luteum. • Lutea = yellow. • Approximate timing

  19. THE FEMALE REPRODUCTIVE SYSTEM: VAGINA • Muscular tube extending between the uterus and the external genitalia. • Hymen: partially/completely blocks the entrance to the vagina before first sexual intercourse or tampon usage.

  20. THE FEMALE REPRODUCTIVE SYSTEM: THE EXTERNAL GENITALIA Areas • Perineum: area including the anus and genitalia • Vulva: area around the genitalia • Vestibule: external area at the opening of the vagina, boundaries are the labia minora. Structures • Clitoris: similar sexual function – arousal-wise – as the penis. It has a tip, called the glans, and corpus cavernosa, which fills with blood and becomes erect during sexual arousal. • Mons pubis: contains adipose tissue and so forms a bulge above the pubic symphysis (small ligament joining the two sides of the pelvic bones). • Labia majora • Labia minora

  21. THE FEMALE REPRODUCTIVE SYSTEM: THE MAMMARY GLANDS • The breasts • Controlled by the hormones of the reproductive system and placenta during pregnancy. • Held up by suspensory ligaments going from the pectoralis major muscle to the dermis of the skin o the breasts. • Lactation: milk production • Anatomy (in this order) • Pectoralis major • Pectoral fat pad • Lobes of the mammary glands • Lactiferous duct • Lactiferous sinus • Nipple (surrounded by areola on surface of the skin)

  22. THE FEMALE REPRODUCTIVE SYSTEM: HORMONES AND THE REPRODUCTIVE CYCLE • GnRH • LH • FSH • Estrogens (including estradiol) • Inhibin • Progesterone

  23. The physiology of sex overview • Male function • Female function

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