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2. Resources Chapter Presentation Visual Concepts Transparencies Standardized Test Prep

3. Reproduction and Development Chapter 43 Table of Contents Section 1 Male Reproduction System Section 2 Female Reproduction System Section 3 Development Section 4 Sexually Transmitted Diseases

4. Section 1 Male Reproductive System Chapter 43 Objectives • Describehow sperm are produced. • Identifythe major structures of the male reproductive system. • Relatethe structure of a sperm cell to its functions. • Sequencethe path taken by sperm as they leave the body.

5. Section 1 Male Reproductive System Chapter 43 The Testes • The roles of a male in sexual reproduction are to produce sperm cells—the male gametes—and to deliver the sperm cells to the female reproductive system to fertilize an egg cell—the female gamete. • Two egg-shaped testes or testicles, are the gamete-producing organs of the male reproductive system. • The testes are located in the scrotum, an external skin sac.

6. Section 1 Male Reproductive System Chapter 43 Structure of the Testes

7. Section 1 Male Reproductive System Chapter 43 The Testes, continued Production of Sperm • Each testis contains hundreds of compartments packed with many tightly coiled tubules, called seminiferous tubules. • Sperm cells are produced through meiosis in the lining of the seminiferous tubules. • Two hormones released by the anterior pituitary regulate the functioning of the testes: luteinizing hormone (LH) and follicle-stimulating hormone (FSH). LH stimulates production of testosterone.

8. Section 1 Male Reproductive System Chapter 43 Male Hormones and Reproduction

9. Section 1 Male Reproductive System Chapter 43 Formation of a Sperm

10. Section 1 Male Reproductive System Chapter 43 The Testes, continued Maturation and Storage of Sperm • After being produced in the seminiferous tubules, the sperm travel through a series of long tubes though they are not yet capable of swimming. • Sperm then enter a long coiled tube called the epididymis. Within each epididymis, the sperm mature and become capable of moving. • From the epididymis, some sperm move to another long tube, the vas deferens.

11. Section 1 Male Reproductive System Chapter 43 Male Reproductive System

12. Section 1 Male Reproductive System Chapter 43 Human Male Reproductive System

13. Section 1 Male Reproductive System Chapter 43 Path of Sperm Through the Male Body

14. Section 1 Male Reproductive System Chapter 43 The Testes, continued Structure of Mature Sperm • A mature sperm cell consists of a head with very little cytoplasm, a midpiece, and a long tail. • Enzymes at the tip of the head help the sperm cell penetrate an egg cell during fertilization. • The midpiece contains many mitochondria that supply sperm with the energy needed to propel themselves through the female reproductive system.

15. Section 1 Male Reproductive System Chapter 43 Sperm Cell

16. Section 1 Male Reproductive System Chapter 43 Parts of a Human Sperm

17. Section 1 Male Reproductive System Chapter 43 The Testes, continued Semen • As sperm cells move into the urethra, they mix with fluids secreted by three exocrine glands: the seminal vesicles, the prostate gland, and the bulbourethral glands. • These fluids nourish the sperm and aid their passage through the female reproductive system. • The seminal vesicles, which lie between the bladder and the rectum, produce a fluid rich in sugars that sperm use for energy.

18. Section 1 Male Reproductive System Chapter 43 The Testes, continued Semen • The prostate gland, which is located just below the bladder, secretes an alkaline fluid that neutralizes the acids in the female reproductive system. • Before semen leaves the body, the bulbourethral glands also secrete an alkaline fluid that neutralizes traces of acidic urine in the urethra. • The mixture of these secretions with sperm is called semen.

19. Section 1 Male Reproductive System Chapter 43 The Testes, continued Delivery of Sperm • The urethra passes through the penis, the male organ that deposits sperm in the female reproductive system during sexual intercourse. • Sperm exit the penis through ejaculation, the forceful expulsion of semen. • After the semen is deposited in the female reproductive system, sperm swim until they encounter an egg cell or until they die.

20. Section 1 Male Reproductive System Chapter 43 The Testes, continued Delivery of Sperm • The penis contains three cylinders of spongy tissue. When the spaces in these cylinders fill with blood, the penis becomes erect.

21. Section 2 Female Reproductive System Chapter 43 Objectives • Describe how eggs are produced. • Identifythe major structures of the female reproductive system. • Analyzethe events of the ovarian and menstrual cycles.

22. Section 2 Female Reproductive System Chapter 43 The Ovaries Production of Eggs • The ovaries are the gamete-producing organs of the female reproductive system. • At birth, the ovaries contain about 2 million immature egg cells that already have begun the first division of meiosis. • When an egg cell matures, it is called an ovum.

23. Section 2 Female Reproductive System Chapter 43 Ovaries and Uterus

24. Section 2 Female Reproductive System Chapter 43 Formation of an Ovum

25. Section 2 Female Reproductive System Chapter 43 The Ovaries, continued Structures of the Female Reproductive System • When an ovum is released from an ovary, cilia sweep the ovum into a fallopian tube. Each fallopian tube is a passageway through which an ovum moves from an ovary toward the uterus. • The uterus is a hollow, muscular organ. • During sexual intercourse, sperm are deposited inside the vagina, a muscular tube that leads from the outside of the female’s body to the entrance to the uterus.

26. Section 2 Female Reproductive System Chapter 43 Female Reproductive System

27. Section 2 Female Reproductive System Chapter 43 Human Female Reproductive System

28. Section 2 Female Reproductive System Chapter 43 Path of an Egg Through the Female Body

29. Section 2 Female Reproductive System Chapter 43 The Ovum • The ovaries prepare and release an ovum in a series of events collectively called the ovarian cycle. • The release of an ovum from an ovary is called ovulation. • The ovum is then swept into the fallopian tube and begins to move toward the uterus, awaiting fertilization. • Although the duration of the ovarian cycle varies, the cycle generally spans about 28 days.

30. Section 2 Female Reproductive System Chapter 43 The Ovum, continued Phases of the Ovarian Cycle During the ovarian cycle, ovulation occurs about every 28 days.

31. Section 2 Female Reproductive System Chapter 43 The Ovum, continued Phases of the Ovarian Cycle: Follicular Phase • A follicle is a cluster of cells that surrounds an immature egg cell and provides the egg with nutrients. • During the follicular phase of the ovarian cycle, hormones regulate the completion of an egg cell’s maturation. • The follicular phase begins when the anterior pituitary releases follicle-stimulating hormone (FSH) and luteinizing hormone (LH).

32. Section 2 Female Reproductive System Chapter 43 The Ovum, continued Phases of the Ovarian Cycle: Ovulation • As the follicle approaches maturity, it begins to secrete large amounts of estrogen. • The anterior pituitary responds to this high level of estrogen by greatly increasing secretion of LH. • This surge of LH causes the egg cell to complete the first meiotic division, and it causes the follicle and the ovary to rupture. When the follicle bursts, ovulation occurs.

33. Section 2 Female Reproductive System Chapter 43 The Ovum, continued Phases of the Ovarian Cycle: Luteal Phase • After ovulation occurs, LH causes the cells of the ruptured follicle to grow, forming a corpus luteum. • A corpus luteum is a yellowish mass of follicular cells that functions like an endocrine gland. • LH causes the corpus luteum to secrete estrogen and progesterone, another sex hormone. This prevents the development of new follicles during the luteal phase.

34. Section 2 Female Reproductive System Chapter 43 Ovarian and Menstrual Cycles

35. Section 2 Female Reproductive System Chapter 43 The Ovum, continued Preparation for Pregnancy • Progesterone signals the body to prepare for fertilization. • If fertilization occurs, the corpus luteum continues to produce progesterone for several weeks. • If fertilization does not occur, production of progesterone slows and eventually stops, marking the end of the ovarian cycle.

36. Section 2 Female Reproductive System Chapter 43 The Ovum, continued Preparation for Pregnancy: Menstrual Cycle • The series of changes that prepare the uterus for a possible pregnancy each month is called the menstrual cycle. • The events of the menstrual cycle are influenced by the changing levels of estrogen and progesterone during the ovarian cycle. • The end of the menstrual cycle coincides with the end of the luteal phase of the ovarian cycle.

37. Section 2 Female Reproductive System Chapter 43 Menstrual Cycle and Hormones

38. Section 2 Female Reproductive System Chapter 43 Menstrual Cycle and Uterine Lining

39. Section 2 Female Reproductive System Chapter 43 The Ovum, continued Menstruation • When the lining of the uterus is shed, blood vessels break and bleeding results. • A mixture of blood and discarded tissue then leaves the body through the vagina. • This process, called menstruation, usually occurs about 14 days after ovulation. • Women eventually stop menstruation. After this event, called menopause, a woman no longer ovulates.

40. Chapter 43 Section 3 Development Objectives • Sequencethe events of fertilization, cleavage, and implantation. • Summarizethe three trimesters of pregnancy. • Describethe effects of drug use on development.

41. Chapter 43 Section 3 Development Fertilization • If sperm are present in the female reproductive system within a few days after ovulation, fertilization may occur. • To fertilize an ovum, a sperm cell must swim to a fallopian tube, where fertilization usually occurs. • During fertilization, the head of the sperm enters the ovum, and the nuclei of the ovum and sperm fuse together. This produces a diploid cell called a zygote.

42. Chapter 43 Section 3 Development Fertilization

43. Chapter 43 Section 3 Development Fertilization, continued Cleavage and Implantation • In the first week after fertilization, the zygote undergoes a series of internal divisions known as cleavage. • Cleavage continues as the zygote moves toward the uterus. By the time it reaches the uterus, the zygote is a hollow ball of cells called a blastocyst. • About six days after fertilization, the blastocyst burrows into the lining of the uterus in an event calledimplantation.

44. Chapter 43 Section 3 Development Early Zygote Development

45. Chapter 43 Section 3 Development Cleavage and Implantation

46. Chapter 43 Section 3 Development Pregnancy • Human development takes about 9 months—a period known as gestation, or pregnancy. • The 9 months of pregnancy are often divided into three trimesters, or 3-month periods. • For the first 8 weeks of pregnancy, the developing human is called an embryo.

47. Chapter 43 Section 3 Development Pregnancy Overview

48. Chapter 43 Section 3 Development Pregnancy, continued First Trimester: Supportive Membranes • In the second week after fertilization—shortly after implantation—the embryo grows rapidly. Membranes that will protect and nourish it also develop. One of these membranes, the amnion, encloses and protects the embryo. • Another membrane, the chorion, interacts with the uterus to form the placenta. • The placenta is the structure through which the mother nourishes the embryo.

49. Chapter 43 Section 3 Development Structure of the Placenta

50. Chapter 43 Section 3 Development Parts of a Placenta