39-3 The Reproductive System Photo Credit: ©David M. Phillips/Photo Researchers Inc. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Sexual Development Puberty is a period of rapid growth and sexual maturation during which the reproductive system becomes fully functional. When puberty ends, reproductive organs are fully developed. Puberty usually begins between the ages of 9 and 15, and usually starts one year earlier in females than in males. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Sexual Development Puberty begins when the hypothalamus signals the pituitary to produce increased levels of two hormones that affect the gonads. These hormones are follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Copyright Pearson Prentice Hall

The Male Reproductive System Release of FSH and LH stimulates cells in the testes to produce testosterone. FSH and testosterone stimulate the development of sperm. Copyright Pearson Prentice Hall

The Male Reproductive System What is the main function of the male reproductive system? Copyright Pearson Prentice Hall

The Male Reproductive System The main function of the male reproductive system is to produce and deliver sperm. Copyright Pearson Prentice Hall

The Male Reproductive System A sperm cell consists of: a head, which contains the nucleus a midpiece, which contains energy-releasing mitochondria a tail, which propels the cell forward Head Nucleus Midpiece Mitochondria The sperm is the male gamete, or sex cell. Tail Copyright Pearson Prentice Hall

The Male Reproductive System Urinary bladder Vas deferens Pubic bone Seminal vesicle Urethra Rectum The main structures of the male reproductive system produce and deliver sperm. The main organs of the male reproductive system are the testes. Penis Prostate gland Epididymis Bulbourethral gland Testis Scrotum Copyright Pearson Prentice Hall

The Male Reproductive System The testes are located in an external sac called the scrotum. The scrotum is located outside the body cavity, where it is between 1 and 3 degrees cooler than normal body temperature. The lower temperature helps sperm development. Copyright Pearson Prentice Hall

The Male Reproductive System Within each testis are clusters of hundreds of tiny tubules called seminiferous tubules. The seminiferous tubules are tightly coiled and twisted together. Sperm are produced in the seminiferous tubules. Copyright Pearson Prentice Hall

The Male Reproductive System Sperm produced in the seminiferous tubules move into the epididymis, where they mature and are stored. From there, sperm move into a tube called the vas deferens, which extends up from the scrotum into the abdominal cavity. This merges with the urethra, the tube that leads to the outside of the body through the penis. Copyright Pearson Prentice Hall

The Male Reproductive System Glands lining the reproductive tract produce seminal fluid. Prostate Gland - Seminal fluid nourishes sperm(fructose) and creates a alkaline(basic) fluid that protects them from the acidity of the female reproductive tract. The combination of sperm and seminal fluid is called semen. Copyright Pearson Prentice Hall

The Female Reproductive System The primary reproductive organs in the female are the ovaries. The ovaries are located in the abdominal cavity. Copyright Pearson Prentice Hall

The Female Reproductive System What is the main function of the female reproductive system? Copyright Pearson Prentice Hall

The Female Reproductive System The main function of the female reproductive system is to produce eggs. In addition, the female reproductive system prepares the female's body to nourish a developing embryo. Copyright Pearson Prentice Hall

The Female Reproductive System Fallopian tube Ovary Uterus Cervix Urinary bladder Rectum Pubic bone The main function of the female reproductive system is to produce ova. The ovaries are the main organs of the female reproductive system. Vagina Urethra Copyright Pearson Prentice Hall

The Female Reproductive System Puberty in females starts when the hypothalamus signals the pituitary gland to release FSH and LH. FSH stimulates cells within the ovaries to produce estrogen. Copyright Pearson Prentice Hall

The Female Reproductive System Egg Development  Each ovary contains about 400,000 primary follicles, which are clusters of cells surrounding a single egg. The follicle helps an egg mature for release into the reproductive tract, where it can be fertilized. Eggs develop within their follicles. Copyright Pearson Prentice Hall

The Female Reproductive System Egg Release When a follicle has matured, its egg is released in a process called ovulation. The follicle breaks open, and the egg is swept from the ovary into one of the two Uterine tubes. While in the Fallopian tube, an egg can be fertilized. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall

The Female Reproductive System After a few days, the egg passes from the Fallopian tube into the uterus. If the egg is not fertilized it passes through the cervix, and finally out of the vagina. The vagina leads to the outside of the body. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall

Sexually Transmitted Diseases Diseases that spread from one person to another during sexual contact are called sexually transmitted diseases (STDs). STDs are a serious problem in the U.S., infecting millions of people each year and accounting for thousands of deaths. Copyright Pearson Prentice Hall

Sexually Transmitted Diseases STDs caused by bacteria include chlamydia, syphilis, and gonorrhea. STDs caused by viruses include hepatitis B, genital herpes, genital warts, and HIV/AIDS. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 39-3 Which statement best describes male sperm cells? They are motile, produced in small numbers, and larger than most body cells. They are motile, produced in large numbers, and smaller than most body cells. They are nonmotile, produced in small numbers, and larger than most body cells. They are nonmotile, produced in large numbers, and smaller than most body cells. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 39-3 The menstrual cycle is regulated by hormones that are controlled by positive feedback mechanisms. ovulation. negative feedback mechanisms. fertilization. Copyright Pearson Prentice Hall

END OF SECTION