The document provides an overview of mammalian reproduction, detailing the structure and function of female and male reproductive organs, as well as the hormonal regulation of the reproductive system. It highlights the roles of various glands and tissues in reproduction and sexual development, including mammary glands, ovaries, testes, and hormones. Additionally, it compares the menstrual cycle in humans with the estrous cycle in other mammals.

1. MAMMALIAN REPRODUCTION<br />Mammary glands<br />“Mammary glands are present in both sexes but normally produce milk only in females. Though not part of the reproductive system, the female mammary glands are important to reproduction. Within the glands, small sacs of epithelial tissue secrete milk, which drains into a series of ducts opening at the nipple. The breasts contain connective and fatty (adipose) tissue in addition to the mammary glands. Because the low level of estradiol in males limits the development of the fat deposits, male breasts usually remain small.”<br />Structure <-> Function

2. Female

3. StructureFunctionfolliclesStructure in the ovary that contains oocyte, a partially developed egg. It also releases a primary female sex hormone, estrogen, specifically estradiolCorpus luteumA tissue in the ovary that forms from the collapsed follicle after ovulation. It secretes additional estradiol and progesterone which helps maintain the uterine lining during pregnancyOviduct/fallopian tubeA tube connecting the ovary to the uterus. Using wavelike motions, the eggs released from the ovary is brought to the uterusOvaryproduces female gametes and reproductive hormones.Uterusa.k.a the womb. It is where eggs are fertilized and developendometriumInner lining of the uterus that is rich in blood vessels. The rich supply of blood vessels allow an optimal situation for implantation of blastocystcervixNeck of the uterus; leads to the vagina; mucus forms plug to prevent infection; allows the flow of blood from uterus to vagina; directs the sperm into uterusvaginaMuscular but elastic chamber; site for insertion of penis and deposition of sperm during copulation; serves as birth canal and opens to the vulva, the external female genitalia Labia majoraThick, fatty ridges that protect the rest of the vulvaLabia minoraSlender skin folds that borders the vaginal opening and the separate opening of the urethraHymenThin piece of tissue that partly covers the vagina; ruptured during sexual intercourseclitorisLocated at the upper intersection of the labia minora; consists of a short shaft, glans/head and prepuce(fold of skin covering the glans); richly supplied with nerve endings, making it one of the most sensitive points of sexual stimulation; becomes erect during arousalBartholin’s glandsLocated slightly below and to the left and right of the vaginal opening; secretes mucus to lubricate the vagina

4. MaleStructureFunctionTestes (singular, testis)Male reproductive organ in which sperm and reproductive hormones are producedSeminiferous tubulesHighly coiled tubes in the testis that produce spermLeydig cellsScattered between seminiferous tubules; produce testosterone and androgenScrotum Houses the testes; maintains the temp required for spermatogenesis. (which is about 2 degrees Celsius lower than the temp in the abdominal cavity)epididymisCoiled tubule adjacent to the testes; storage area of spermVas deferensDuring ejaculation, the sperm is propelled through this muscular duct from the epididymis to the urethra.Ejaculatory ductTransports sperm from the vas deferens to the urethra; the convergence between the vas deferens and a duct from the seminal vesicleUrethra Outlet tube for both the excretory system and the reproductive system (urine and semen)Seminal vesicle“A gland in males that secretes a fluid component of semen that lubricates and nourishes sperm”; fructoseSemenFluid ejaculated by male during orgasm; contains sperm and secretions from the following glandsProstate gland“A gland in human males that secretes an acid-neutralizing component of semen”; for acidity of the vaginal tract; contains anticoagulant enzymes and citrate (a sperm nutrient)Bulbourethral glandEven before ejaculation, it secretes clear mucus that neutralizes any acidic urine in the urethra. Also contains sperm -> high failure rate for coitus interruptusPenis An external reproductive organ; contains the urethra and 3 cylinders of erectile tissue; its erection allows insertion into the vagina; baculum- bone in the penis which provides further stiffening (present in rodents, raccoons, walruses, whales, and several other mammals). glans penis-head of the penis and more sensitive to sexual stimulation.<br />323850325120Terms:Coitus-sexual intercourseVasocongestion –filling of tissue with bloodMyotonia– increased muscle tension00Terms:Coitus-sexual intercourseVasocongestion –filling of tissue with bloodMyotonia– increased muscle tensionThe Human Sexual Response

5. 264795038735Acrosome – contains hydrolytic enzymes that digest the membrane of the egg cell and help the sperm in penetrating the egg00Acrosome – contains hydrolytic enzymes that digest the membrane of the egg cell and help the sperm in penetrating the eggGamete Structure

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8. E

9. Regulation of Human Reproductive System by Sex Hormones

10. Hypothalamus, anterior pituitary glands and gonads govern human reproduction

11. Hypothalamus –secretes-> gonadotropin releasing hormmones (GnRH).

12. Anterior pituitary –GnRH-> follicle-stimulating hormone (FSH) + lutenizing hormone (LH)

13. FSH and LH regulate gametogenesis:

14. Direct: target tissues in the gonads

15. Indirect: sex hormone production (principally, steroid hormones)

16. Sex hormones also regulate gametogenesis:

17. Effect of sex hormones:

18. Male:

19. Male vocalizations

20. Development of primary sex characteristics, structures (e.g. seminal vesicles0

21. Deeper voice

22. Development of facial and pubic hair

23. Growing of muscles

24. Specific sexual behaviours and sex drive (generally, an increase in aggressiveness)

25. Female:

26. Development of breast and pubic hair

27. Influence on sexual behaviour

28. Fat deposits induced in breasts and hips

29. Increased water retention

30. Alteration of calcium metabolism

31. Hormonal Control of the Male Reproductive System

32. Ovarian and Uterine (Menstrual Cycle)

33. REFER TO STEPS BELOW AS TO WHAT THE NUMBERS IN THE FIGURE MEAN

34. Release of GnRH from hypothalamus

35. GnRH stimulates anterior pituitary to release FSH and LH

36. FSH, aided by LH, stimulates follicle growth

37. Estradiol secretion by growing follicles

38. Estradiol secretion rises steeply

39. ↑FSH, ↑LH (+ feedback)

40. Maturing follicle grows very large; follicle & adjacent wall of the ovary ruptureOVULATION – ovum is released from ovary to fallopian tube<br />Remaining follicular tissue (stimulation by LH) -> corpus luteum

41. ↑estradiol, ↑progesterone causes negative feedback on the release of LH and FSH (↓LH, ↓FSH)

42. ↓gonadotropin levels causes the corpus luteum to disintegrate

43. ↓estradiol, ↓progesterone which ends the negative feedback (FSH and LH levels increase)

44. Enough FSH stimulates the growth of new folliclesProliferative phase – coincides with follicular phase; estradiol by growing follicles -> endometrium thickens<br />Secretory phase – coincides with luteal phase; estradiol and progesterone causes development & maintenance of uterine lining, enlargement of arteries and growth of endometrial glands. (these glands secrete nutrient fluid, hence it is called the secretory phase)

45. Menstrual flow phase/menstruation

46. ↓ovarian hormone levels, endometrial arteries constrict

47. ↓circulation, uterine lining disintegrates, uterus contracts

48. Blood vessels constrict -> blood released and shed along with endometrial tissue & fluid

49. Menstruation VS Estrous <br />Menstruation cycleEstrous cycleOccurs in humans and primatesOccurs in other mammalsShedding of the endometrium Reabsorption of endometriumCan be sexually active even if they are not ovulatingGenerally only sexually active during the cycle [in heat]Reference:<br /> BIBLIOGRAPHY \l 13321 Campbell, N. A. (2008). Biology (8th ed.). San Francisco, California, United States of America: Pearson Education, Inc.<br />