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1. HUMAN REPRODUCTIVE SYSTEM BERNADETTE V. PANGILINAN LUMAMPONG INTEGRATED NATIONAL HIGH SCHOOL

2. What is Reproduction? Reproduction is a biological process by which an organism reproduces an offspring that is biologically similar to the organism. Reproduction enables and ensures the continuity of species, generation after generation. It is the main feature of life on earth.

3. Types of Reproduction There are basically two types of reproduction: 1. Asexual Reproduction 2. Sexual Reproduction

4. THE REPRODUCTIVE SYSTEM Male and female reproductive systems develop from similar embryonic tissue. First few weeks of development, male and female embryos are indistinguishable. Adult reproductive systems share some functional similarities.

5. THE MALE REPRODUCTIVE SYSTEM

6. MALE REPRODUCTIVE SYSTEM

7. MALE REPRODUCTIVE SYSTEM Esternal Structures Penis : Deposits sperms into the vagina during mating Scrotum : Sac of skin that holds the testis Internal Structures Prostate : exocrine gland of male reproductive system Vas Deferens : tubes connecting epididymis to ejaculatory ducts Epididymis : organ where sperm matures Testicles : organ where sperm is created Urethra : tube that connects bladder to outside of body Cowper’s Gland: secretes lubricating fluid Seminal Vesicle: make semen (seminal fluid)

8. 8 PENIS the penis is the male sex organ, reaching its full size during puberty. In addition to its sexual function,

9. 9 SCROTUM Sac of skin and superficial fascia that hangs outside the abdominopelvic cavity at the root of the penis Contains paired testicles separated by a midline septum Its external positioning keeps the testes 35°C lower than core body temperature

10. TESTICLE/ TESTIS 10 organ where sperm is created

11. 11

12. 12 SPERMATIC CORD Contains the structures running from the testicles to the pelvic cavity. Passes through the inguinal canal Contents: Vas Deferens Nerves Blood Vessels

13. 13 ACCESSORY GLANDS: SEMINAL VESICLES Lie on the posterior wall of the bladder and secrete 60% of the volume of semen Seminal fluid: Fructose : provides energy for the sperm. Fibrinogen : helps turn semen into a bolus that can be readily propelled into the vagina. Prostaglandins : decrease cervical mucus viscosity and stimulate reverse peristalsis of the uterus. Join the ductus deferens to form the ejaculatory duct

14. 14 POSTERIOR BLADDER

15. 15 ACCESSORY GLANDS: PROSTATE GLAND Doughnut-shaped gland that encircles part of the urethra inferior to the bladder Plays a role in the activation of sperm Enters the prostatic urethra during ejaculation Prostatic secretions include: Citrate : is a food source (TCA cycle) Proteolytic enzymes : acts to "decoagulate" the semen that was coagulated by seminal vesicle secretions, which helps the sperm begin their journey once inside the vagina

16. 16 BULBOURETHRAL GLANDS (COWPER’S GLANDS) Pea-sized glands inferior to the prostate Produce alkaline mucus prior to ejaculation that neutralizes traces of acidic urine in the urethra

17. 17 SEMINIFEROUS TUBULES

18. 18 EPIDIDYMIS Epididymis: Storage and maturation area for sperm Its head joins the efferent ductules and caps the superior aspect of the testis The duct of the epididymis has stereocilia that: Absorb testicular fluid Pass nutrients to the sperm Nonmotile sperm enter, pass through its tubes and become motile (propelled by peristalsis) Upon ejaculation the epididymis contracts, expelling sperm into the ductus deferens

19. 19 SPERMATOGENESIS Spermatogenic stem cells of the seminiferous tubules give rise to sperm in a series of events Mitosis of spermatogonia, forming spermatocytes Meiosis forms spermatids from spermatocytes Spermiogenesis: spermatids form sperm

20. 20 SPERMATOGENESIS

21. 21 SPERMIOGENESIS: SPERMATIDS TO SPERM

22. 22 SPERM Sperm have three major regions Head :contains DNA and has a helmet-like acrosome containing hydrolytic enzymes that allow the sperm to penetrate and enter the egg Midpiece : contains mitochondria spiraled around the tail filaments Tail :a typical flagellum produced by a centriole

23. 23 SPERM SUMMARY Produced : Seminiferous tubules Stored: Epididymis Transported through epididymis by rhythmic peristaltic contractions as they mature Epididymis 🡪 Vas Deferens 🡪 Ejaculatory duct (ampulla of vas deferens fuses with duct of seminal vesicle “ejaculatory duct”) 🡪 prostate 🡪 prostatic urethra (then passes the bulbourethral gland) 🡪 membranous urethra 🡪 penile urethra

24. The Sperm Pathway Vas deferens Expulsion from the body Testes Sperm Epididymis Seminal vesicles Ejaculatory duct Prostate gland Urethra The Sperm Pathway

25. THE FEMALE REPRODUCTIVE SYSTEM

26. 26 FEMALE: LATERAL VIEW

27. 27 Fornix Endocervical canal

28. GROSS ANATOMY The ovaries are solid, ovoid structures, about 2 cm in length and 1 cm in width. Like the testes, they develop from embryonic tissue along the posterior abdominal wall, near the kidneys. Accessory organs include the uterine tubes, uterus, and vagina.

29. 29 UTERINE TUBES (FALLOPIAN TUBES) Receive the ovulated oocyte and provide a site for fertilization Empty into the superolateral region of the uterus via the isthmus Expand distally around the ovary forming the ampulla The ampulla ends in the funnel-shaped, ciliated infundibulum containing fingerlike projections called fimbriae

30. 30 UTERINE TUBES (FALLOPIAN TUBES) Function: events occurring in the uterine tube Fimbriae sweep oocyte into tube, cilia & peristalsis move it along, sperm reaches oocyte in ampulla, fertilization occurs within 24 hours after ovulation & zygote reaches uterus about 7 days after ovulation

31. 31 UTERUS Hollow, thick-walled organ located in the pelvis anterior to the rectum and posterosuperior to the bladder Body: Major portion of the uterus Fundus : Rounded region superior to the entrance of the uterine tubes Isthmus: Narrowed region between the body and cervix

32. 32 UTERUS

33. 33 UTERINE HISTOLOGY Endometrium Simple columnar epithelium Stroma of connective tissue and endometrial glands Stratum functionalis : Shed during menstruation Stratum basalis : Replaces stratum functionalis each month Myometrium 3 layers of smooth muscle Perimetrium Visceral peritoneum

34. ENDOMETRIUM Proliferative phase : glands and blood vessels scattered throughout the functional zone with little or no branching. New glands form and endometrium thickens. Secretory phase : glands are enlarged and have branches. Preparing the endometrium for implantation If no implantation then endometrium breaks down and menstruation begins.

35. 35 CERVIX Narrow lower neck of the uterus which projects into the vagina inferiorly Cervical canal – cavity of the cervix that communicates with: The vagina via the external os The uterine body via the internal os Cervical glands secrete mucus that covers the external os and blocks sperm entry except during midcycle

36. 36 Fornix Endocervical canal

37. 37 VAGINA Thin-walled tube lying between the bladder and the rectum, extending from the cervix to the exterior of the body Wall consists of three coats: fibroelastic adventitia, smooth muscle muscularis, and a stratified squamous mucosa Mucosa near the vaginal orifice forms an incomplete partition called the hymen Vaginal fornix : upper end of the vagina surrounding the cervix

38. 38 FEMALE EXTERNAL GENITALIA Mons pubis : fatty pad over the pubic symphysis Labia majora & minora : folds of skin encircling vestibule where find urethral and vaginal openings Clitoris : small mass of erectile tissue Bulb of vestibule : masses of erectile tissue just deep to the labia on either side of the vaginal orifice Perineum: Area between the vagina and anus

39. 39 MAMMARY GLANDS Modified sweat glands that produce milk (lactation) Amount of adipose determines size of breast Milk-secreting glands open by lactiferous ducts at the nipple Areola is pigmented area around nipple Suspensory ligaments suspend breast from deep fascia of pectoral muscles (aging & Cooper’s droop) Mammary line is a thickened ridge of embryonic tiwwue that extends from the axilla to the groin.

40. 40 BREAST

41. 42 LYMPHATIC DRAINAGE Lymph nodes draining the breast are located in the axilla.

42. OOGENESIS: BEFORE BIRTH 43 During fetal development, oogonia (stem cells) divide by mitosis to make primary oocytes Primary oocytes begin meiosis and stop in prophase I until puberty Primordial follicles: Support cells that surround the oocyte in the ovary 2 million present at birth 400,000 remain at puberty

43. 44 OOGENESIS: AFTER PUBERTY Each month, hormones cause several follicles to develop, which triggers the primary oocyte to resume meiosis I Polar bodies: When the cell divides, all the cytoplasm and organelles stay with one of the new cells, the other cell is just DNA, and is called a polar body and is discarded Secondary oocyte : The stage at which ovulation occurs.

44. 45 OOGENESIS: AFTER PUBERTY The secondary oocyte begins meiosis II, but stops in metaphase II The secondary oocyte is ovulated Meiosis II is completed only if it is fertilized.

45. 46 OOGENESIS

46. 47 LIFE HISTORY OF OOGONIA As a fetus, oogonia divide to produce millions by mitosis but most degenerate (atresia) Some develop into primary oocytes & stop in prophase stage of meiosis I 200,000 to 2 million present at birth 40,000 remain at puberty but only 400 mature during a woman’s life Each month, hormones cause meiosis I to resume in several follicles so that meiosis II is reached by ovulation Penetration by the sperm causes the final stages of meiosis to occur

47. 48 OVARIES Each follicle consists of an immature egg called an oocyte Cells around the oocyte are called: Follicle cells (one cell layer thick) Stimulated to mature by FSH from the pituitary gland Granulosa cells (when more than one layer is present) Thecal cells : Cells in the ovarian stroma Thecal & granulosa cells work together to produce estrogen A protective layer of glycoprotein forms around the egg called the zona pellucida

48. 49 FOLLICLE DEVELOPMENT Primordial follicle : one layer of squamous-like follicle cells surrounds the oocyte Primary follicle: two or more layers of cuboidal granulosa cells enclose the oocyte Secondary follicle: has a fluid-filled space between granulosa cells that coalesces to form a central antrum Graafian follicle : secondary follicle at its most mature stage that bulges from the surface of the ovary Corpus luteum : ruptured follicle after ovulation

49. 50 OVARY HISTOLOGY

50. 51 OVARY HISTOLOGY

51. 52 Zona pellucida 1° Oocyte (arrested in prophase I) Granulosa cells Thecal cells Nucleus Primordial follicle Primary Follicle

52. 53 SECONDARY FOLLICLE Fluid-filled antrum

53. 54 GRAAFIAN FOLLICLE Fluid filled antrum Granulosa cells Oocyte 2° Corona radiata Stalk Zona pellucida

54. CORPUS LUTEUM After ovulation, the remains of the follicle are transformed into a structure called the corpus luteum . If a pregnancy occurs, it produces progesterone to maintain the wall of the uterus during the early period of development.

55. CORPUS ALBICANS If fertilization does not occur, the corpus luteum will begin to break down about 2 weeks after ovulation. Degeneration occurs when fibroblasts enter the corpus luteum and a clump of scar tissue forms called the corpus albicans .

56. OVARIAN AND UTERINE CYCLES

57. OVARIAN CYCLE Monthly changes that occur in the ovary during a woman’s reproductive life. Each month FSH stimulates primordial follicles to grow and mature ( follicular phase) Ovulation - release of the egg (LH) Luteal phase the corpus luteum produces progesterone that maintains uterine walls If fertilization does not occur, the corpus luteum degenerates, within 2 weeks into a mass of scar tissue called the corpus albicans

58. FEMALE REPRODUCTION Unlike males, who are able to produce sperm cells throughout their reproductive lives, females produce a finite number of egg cells. During early fetal development germ cells migrate into the ovaries and differentiate into oogonia

59. OOGONIA The oogonia divide by mitosis for the next few months and some differentiate into primary oocytes. By fifth month there are about 7 million primary oocytes, but most will degenerate during the next 2 months

60. OOGONIA Those that remain will be surrounded by a single layer of squamous epithelial cells (follicle cells) called a primordial follicle. Degeneration of primary oocytes continues. At birth =1million primordial follicles At puberty 400,000 remain Only 400-500 will reach maturity