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Mammalian Reproduction

Mammalian Reproduction. GERONIA rey || MABUNGA ronn MACINAS ian || MALONZO dindo MATANGUIHAN joem || MATUBA sam REYES yves || SALAZAR carl SAN PEDRO victor || BAUTISTA denise. III - Rb. Male Reproductive System. Male Reproductive System. Female Reproductive System.

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Mammalian Reproduction

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  1. Mammalian Reproduction GERONIA rey || MABUNGA ronn MACINAS ian || MALONZO dindo MATANGUIHAN joem || MATUBA sam REYES yves || SALAZAR carl SAN PEDRO victor || BAUTISTA denise III - Rb

  2. Male Reproductive System

  3. Male Reproductive System

  4. Female Reproductive System

  5. Female Reproductive System

  6. Two types of physiological reactions predominate in both sexes: vasocongestion – filling of a tissue with blood due to increase blood flow myotonia – increased muscle tension Human Sexual Response

  7. Human Sexual Response • Four phases: • Excitement • Plateau • Orgasm • Resolution

  8. Excitement • Preparation of vagina and penis for coitus • Vasocongestion is evident in the penis and clitoris • Enlargement of the testes, labia, and breasts • Vaginal lubrication • Myotonia may occur, eg., nipple erection and tension of arms and legs

  9. Plateau • Outer third of the vagina becomes vasocongested, inner two thirds slightly expanded • Breathing increases and heart rate rises (up to 150 beats per minute) as a response to stimulation of autonomic nervous system

  10. Orgasm • Rhythmic, involuntary contractions of the reproductive structures • Males: emission and expulsion/ejaculation • Shortest phase, lasting only a few seconds • Contractions occur at 0.8-sec intervals

  11. Resolution • Vasocongested organs return to normal size and color • Muscles relax • Most changes happen in 5 minutes • Penile and clitoral erection may take longer to return to normal size and color

  12. Human Sexual Response “Sex could kill you. Do you know what the human body goes through when you have sex? Pupils dilate, arteries constrict, core temperature rises, heart races, blood pressure skyrockets, respiration becomes rapid and shallow, the brain fires bursts of electrical impulses from nowhere to nowhere, and secretions spit out of every gland, and the muscles tense and spasm like you're lifting three times your body weight. It's violent, it's ugly and it's messy, and if God hadn't made it unbelievably fun, the human race would have died out eons ago.” - Cameron (House MD, Season 1, Occam’s Razor)

  13. The Sperm

  14. Spermatogenesis Making of Sperms

  15. The Egg

  16. Oogenesis – making of eggs

  17. Ovulation • Two phases in the ovarian cycle • Follicular phase • Luteal phase

  18. Follicular Phase • Several follicles begin to grow • Egg cells enlarge; coat of follicles become multilayered • Only one follicle grows, others die • Maturing follicle develops an internal fluid-filled cavity and grows very large • Ends with ovulation, the release of the egg cell from the follicle

  19. Luteal Phase • Remaining follicular tissue develops into the corpus luteum • Corpus luteum – endocrine tissue that secretes female hormones during the phase

  20. Hormonal Control • Gonadotropin-releasing hormones (GnRH) • Released by the hypothalamus • Stimulates production of FSH and LH in the anterior pituitary • Follicle-stimulation hormone (FSH) • Stimulates formation of follicles in the ovaries • Luteinizing hormone (LH) • Stimulates remaining follicular tissue after ovulation to form the corpus luteum

  21. Hormonal Control • During the follicular phase: • GnRH stimulates production of FSH and LH • FSH stimulates follicle growth • Growing follicles release estrogens • Small increase in estrogens inhibit secretion of FSH and LH • High concentration of estrogens stimulates the secretion of FSH and LH by triggering the production of GnRH

  22. Hormonal Control • Increase in LH stimulated by increase in estrogens stimulates maturation of the follicle (positive feedback) • Ovulation occurs a day after the LH surge

  23. Hormonal Control • During the luteal phase: • LH stimulates transformation of follicular tissue into the corpus luteum • Corpus luteum secretes estrogens and progesterone • Increase in estrogens and progesterone cause negative feedback on the hypothalamus and pituitary, inhibiting secretion of FSH and LH

  24. Hormonal Control • Disintegration of corpus luteum causes a decline in estrogens and progesterone • This in turn liberates the hypothalamus and pituitary from the inhibitory effects of these hormones

  25. Ovulation

  26. Menstrual vs. Estrous • In both cases, ovulation occurs after the endometrium has started to thicken • In menstrual cycles, the endometrium is shed in a bleeding called menstruation • In estrous cycles, the endometrium is reabsorbed by the uterus; no extensive bleeding occurs

  27. Menstrual vs. Estrous • Estrous cycles include more pronounced behavioral changes and stronger effects of season and climate • Estrus (L. oestrus, “frenzy”, “passion”) • Period of sexual activity • Vaginal changes during this period permits mating

  28. Thank You for Listening!

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