1. The Reproductive System

2. Introduction Reproduction is the mechanism by which the thread of life is sustained Reproduction is the mechanism by which the thread of life is sustained Single cell duplicates its genetic material Genetic material is passed from generation to generation

3. Groups of Organs Gonads – (testes and ovaries) Gonads – (testes and ovaries) Produce gametes (sperm cells and ova) Ducts Ducts Transport, receive, or store gametes Accessory sex glands Accessory sex glands Produce material that support gametes

4. The Male Reproductive System

5. Organs of the Male Reproductive System Scrotum Scrotum Testes Testes Epididymus Epididymus Vas deferens Vas deferens Urethra Urethra Penis Penis

6. The Male Reproductive System

7. The Scrotum Pouch that supports the testes Pouch that supports the testes Consists of skin and superficial fascia Consists of skin and superficial fascia Internally Internally Divided into 2 sacs Each contains 1 testis Each contains 1 testis Muscle fibers regulate temperature of testes Muscle fibers regulate temperature of testes Production and survival of sperm require a temperature that is lower than normal body temp.

8. The Testes Paired oval glands Paired oval glands Development Development High on embryo’s abdominal wall Begin descent into scrotum during latter ½ of 7 th month Cryptorchism – testes do not descend Cryptorchism – testes do not descend

9. Descent of Testes

12. Structure of a Testis Divided into internal compartments Divided into internal compartments Each contains tightly coiled seminiferous tubules Spermatogenesis = production of sperm Spermatogenesis = production of sperm

13. The Testes

14. Seminiferous Tubules

15. A Few Concepts with Regards to the Formation of Gametes In sexual reproduction, a new organism is produced by the union and fusion of sex cells called gametes In sexual reproduction, a new organism is produced by the union and fusion of sex cells called gametes A zygote results from the union and fusion of gametes A zygote results from the union and fusion of gametes Contains a mixture of chromosomes (DNA) form the 2 parents Zygote repeatedly divides (mitosis), develops into a new organism Zygote repeatedly divides (mitosis), develops into a new organism Gametes differ from all other body cells in that they contain ½ the number of chromosomes Gametes differ from all other body cells in that they contain ½ the number of chromosomes Human cells have 23 chromosomes (haploid, or n) = 1 set Or 46 chromosomes (diploid, or 2n) = 23 pairs, or 2 sets Meiosis = a process of cell division by which gametes are produced in the testes and ovaries; receive the haploid chromosome number (n) Meiosis = a process of cell division by which gametes are produced in the testes and ovaries; receive the haploid chromosome number (n)

16. Spermatogenesis

17. Migration of Spermatozoa (Ducts) Sperm are stored in the epidymus, Sperm are stored in the epidymus, Then transported through the vas deferens, Then transported through the vas deferens, Leave the body through the urethra Leave the body through the urethra Seminal fluids (semen) are added to the sperm by accessory glands Seminal fluids (semen) are added to the sperm by accessory glands seminal vesicles prostate gland bulbourethral gland

18. Accessory Glands

19. Semen Mixture of sperm and secretions from accessory glands Mixture of sperm and secretions from accessory glands Average volume for each ejaculation Average volume for each ejaculation 2.5 – 5 ml Average # sperm/ejaculation Average # sperm/ejaculation 50 – 100 million/ ml. = 125 – 500 million/ejaculation Only a small % reach ovum Only a small % reach ovum Many sperm cells act on ovum to dissolve the barrier Only 1 enters the ovum

20. Spermatozoa Produced at the rate of about 300 million/day Produced at the rate of about 300 million/day Once ejaculated Once ejaculated Life expectancy of about 48 hours in the female reproductive tract Structure Structure Head with acrosome Midpiece Tail (flagellum)

21. Structure of Sperm

22. The Female Reproductive System

23. Organs of the Female Reproductive System Ovaries (paired) Ovaries (paired) Fallopian tubes Fallopian tubes Uterus Uterus Vagina Vagina

24. The Female Reproductive System

26. Ovaries Located in the upper pelvic cavity Located in the upper pelvic cavity Oogenesis = formation of haploid ovum by meiosis Oogenesis = formation of haploid ovum by meiosis Essentially the same as spermatogenesis, but division of cytoplasm is uneven

27. Oogenesis

28. Process of Ova Development Before birth, many primordial follicles formed Before birth, many primordial follicles formed Begin meiosis, but stop at chromosome duplication At puberty, every month At puberty, every month FSH causes ovaries to enlarge Primordial follicles mature Oocyte becomes larger Follicle cells divide Follicle fills with fluid, oocyte pressed to 1 side

29. Ova Development

32. Ovulation Ovum undergoes 1 st meiotic division Ovum undergoes 1 st meiotic division Ovum is released into peritoneal cavity Ovum is released into peritoneal cavity Ovum is propelled to the fallopian tube Ovum is propelled to the fallopian tube If not fertilized, it degenerates If fertilized, 2 nd meiotic division occurs

33. Ovulation

34. Formation of Corpus Luteum

35. Fallopian Tubes Paired Paired Extend laterally from uterus, toward ovary, but not attached Extend laterally from uterus, toward ovary, but not attached Function Function Transport ova Fertilization occurs Ectopic pregnancy Ectopic pregnancy Development of embryo or fetus outside the uterine cavity

36. Uterus Functions Functions Site of menstruation Implantation of fertilized ovum Development of fetus during pregnancy Labor Location Location Between the bladder and rectum Structure StructureBodyCervix 3 layers 3 layersEndometriumMyometriumPerimetrium Papanicolaou test = Pap smear Papanicolaou test = Pap smear

37. Fallopian Tubes and the Uterus

38. The Uterine Wall

39. Changes in the Endometrium

40. Vagina Function Function Passageway for menstrual flow Receptacle for penis during intercourse Lower portion of the birth canal Structure StructureMuscular Lined with mucous membrane pH is low

41. The Female Reproductive Cycle Ova (oocytes) are produced in the ovaries (oogenesis) Ova (oocytes) are produced in the ovaries (oogenesis) Approximately every 28 days one ovum is expelled from the ovary (ovulation) Approximately every 28 days one ovum is expelled from the ovary (ovulation) An ovum transported through the fallopian tube to the uterus where it becomes embedded in the uterine lining An ovum transported through the fallopian tube to the uterus where it becomes embedded in the uterine lining Fertilization occurs in the fallopian tube If the egg is not fertilized, the uterine lining detaches and is shed in menstruation If the egg is not fertilized, the uterine lining detaches and is shed in menstruation If the egg is fertilized, the uterine lining is held in place and supported by progesterones If the egg is fertilized, the uterine lining is held in place and supported by progesterones