Ch. 43 Reproductive System

1. Ch. 43 Reproductive System By: Brianna Shields June 6, 2006

2. GOAL • Describe how sperm are produced • Identify the major structures of the male reproductive system • Sequence the path taken by sperm as they leave the body • Describe how eggs are produced • Identify the major structures of the female reproductive system • Analyze the events of the ovarian and menstrual cycles • Sequence the events of fertilization, cleavage and implantation • Summarize the three trimesters of pregnancy • Describe the effects of drug use on development • Identify the causes and symptoms of several bacterial STDs • Identify the causes and symptoms of several viral STDs • Compare the treatment and cure rates of viral STDs with those of bacterial STDs

3. TESTES Two, egg-shaped, located in scrotum sacs Gamete producing organs Hang externally (temperature is 3 degrees lower than the body’s temperature)- normal body temp is too high for sperm production Seminiferous tubules- coiled tubules packed inside testis that produce sperm cells through meiosis Testes regulated by pituitary Luteinizing hormone- stimulates secretion of sex hormone testosterone Follicle stimulating hormone- stimulates sperm production Male Reproductive System

4. TESTES Several hundred million sperm cells produced each day Created in seminiferous tubules Travel to epididymis tube where they mature (and are stored) Enter long tube: vas deferens that connects to urethra Sperm exits body through urethra duct (just like urine does) Male Reproductive System

6. TESTES Sperm structure Head- contains enzymes for penetrating egg (only head enters egg) Midsection- contains mitochondria for powering the sperm Tail- powerful whip-like flagella for locomotion Male Reproductive System

8. TESTES Semen Sperm in urethra mix with fluids from the seminal vesicles, prostate gland and bulbourethral glands Seminal Vesicle Fluid- rich in sugars to provide sperm with energy Prostate Gland Fluid- alkaline fluid that neutralizes acidity in female reproductive tract Bulbourethral Gland Fluid- alkaline fluid that neutralizes traces of urine left in urethra Male Reproductive System

9. TESTES Sperm Delivery Sperm exits urethra through penis during ejaculation (forceful release of semen) During sexual arousal, blood flow to penis increases causing it to become rigid and erect Once penis deposits semen in female reproductive system, the sperm must swim to the egg in order to fertilize it Men with less than 20 million sperm per ml are considered sterile Male Reproductive System

10. ASSESSMENT • Sequence the path that mature sperm take from the testes to the outside of the body • Describe the role of each part of a mature sperm cell • How do secretions by exocrine glands help the delivery of sperm to the female reproductive system • Describe the functions of the testes

11. Production of Eggs Ovaries- egg shaped, found in abdominal cavity, produce female gametes (egg cells) Egg cells stall in prophase at beginning of meiosis into female hits puberty (hormones enable meiosis to resume) Females are born with all of the immature egg cells that they will ever have Only 300-400 egg cells will mature over a female’s lifetime Ovum- mature egg cell Female Reproductive System

12. Structures of the female reproductive system Ovary- egg releases once every 28 days Fallopian tube- when released from the ovary, cilia sweep the egg into and through this passageway Journey through fallopian tube takes 3-4 days If egg is not fertilized with 24-48 hours it dies Female Reproductive System

13. Structures of the female reproductive system Egg reaches uterus (small fist sized organ) If fertilized, egg will develop here Vagina- muscular tube where sperm are deposited during sexual intercourse Sperm must swim up through vagina, cervix and into uterus Female Reproductive System

14. Ovarian Cycle Ovaries release an ovum Follicular Phase Regulated by hypothalamus and pituitary In ovary, egg cells mature within follicles (cluster of cells surrounding egg) Follicle stimulating and luteinizing hormone are released into bloostream Follicle produces estrogen Female Reproductive System

16. Ovarian Cycle Ovulation Follicle produces large amounts of estrogen, stimulating pituitary to increase secretion of LH LH causes egg cell to complete first meiotic division Follicle and ovary rupture, ovulation occurs Female Reproductive System

18. Ovarian Cycle Luteal Phase Cells of ruptured follicle grow to form a corpus luteum (yellowish mass of follicular cells) Corpus luteum secretes estrogen and progesterone, inhibiting release of FSH and LH prohibiting the development of new follicles Female Reproductive System

20. Preparation for Pregnancy Progesterone signals body to prepare for fertilization If fertilization doesn’t occur, progesterone production stops, ending the ovarian cycle Menstrual cycle- series of changes preparing the uterus for possible pregnancy each month Uterus lining thickens before menstrual cycle due to increasing levels of estrogen If pregnancy doesn’t occur, estrogen and progesterone levels decrease, causing uterus lining to be shed Female Reproductive System

21. Preparation for Pregnancy Menstruation Uterus lining is shed, blood vessels break resulting in bleeding (blood and tissue leave the body) Women end menstrual cycles by age 45-55 (menopause- woman no longer ovulates and moves out of child bearing phase Female Reproductive System

22. ASSESSMENT • Describe the functions of ovarian follicles • Compare the regulatory roles of LH and FSH • What causes the lining of the uterus to thicken and then to be shed during the menstrual cycle? • How could the maturation of an egg cell be halted in the ovary?

23. Development Fertilization Sperm swims to a fallopian tube Sperm penetrates ovum using enzymes in head to break down ovum layers Head of sperm enters ovum Ovum and sperm nuclei fuse to produce a zygote Reproductive System

24. Development Cleavage Series of cell divisions within zygote Occurs as zygote travels through fallopian tube Blastocyst- hollow ball of cells that reaches uterus Implantation- blastocyst burrows into uterine wall Reproductive System

25. Development Pregnancy Gestation- 9 months of pregnancy (3 trimesters) Embryo- first 8 weeks of pregnancy Uterus protects and nourishes baby during pregnancy Reproductive System

26. Development Pregnancy First Trimester Embryo grows rapidly Placenta develops (sac that mother nourishes the embryo through) Mother and baby blood never mix Nutrients from mother diffuse through placenta or pass through umbilical cord Fetus- developing human from 8th week until pregnancy Sex of baby can be determined by end of the first trimester Reproductive System

27. Development Pregnancy Second and Third Trimesters Fetus’ organs become functional Labor- process of leaving the mother’s body due to contractions of the uterus Fetus leaves body through vagina Placenta and umbilical cord expelled after the baby is born Reproductive System

28. ASSESSMENT • Summarize the events in development that occur in the embryo’s first month • Describe the function of the placenta • Describe fetal alcohol syndrome • What are some drugs harmful when they are taken during pregnancy • What might happen if more than one egg were released from the ovaries prior to fertilization?

29. Sexually Transmitted Diseases Pass from person to person during sexual contact Caused by both viruses and bacteria Prevented by abstinence and the use of condoms Reproductive System

30. Sexually Transmitted Diseases Bacterial STDs Most can be successfully treated Many may have mild, unnoticeable symptoms Sterility can result when left untreated Reproductive System

31. Sexually Transmitted Diseases Bacterial STDs Gonorrhea Causes painful urination in discharge of pus from penis and may be symptom free (or discharge from vagina) in females Can spread through reproductive system causing pain, scarring or sterility Reproductive System

32. Sexually Transmitted Diseases Bacterial STDs Syphilis Serious, starts with small chancre ulcer on penis or in vagina Can cause fever, swollen lymph nodes or rash If left untreated, can cause destructive lesions on nervous system, blood vessels, bones, skin Can pass to unborn child Reproductive System

33. Sexually Transmitted Diseases Bacterial STDs Chlamydia Most common Painful urination and vaginal discharge Often goes undetected Can cause scar tissue buildup in fallopian tubes leading to infertility Reproductive System

34. Sexually Transmitted Diseases Bacterial STDs Pelvic Inflammatory Disease Common cause of infertility Inflammation of uterus, ovaries, fallopian tubes or abdominal cavity Results from untreated STDs Click here to watch a video Reproductive System

35. Sexually Transmitted Diseases Viral STDs Cannot be cured/treated with antibiotics AIDS (caused by HIV which destroys wbc’s in immune system) Genital herpes (caused by herpes simplex virus) Periodic outbreaks of painful blisters in genitals, and flu-like symptoms Antiviral drugs can suppress by not cure it Women with it, have greater risk of cervical cancer Can pass to unborn children causing nervous system damage or death Genital warts Hepatitis B Reproductive System

36. ASSESSMENT • Name three common STDs caused by bacteria. Why is early detection of these diseases important? • Describe how HIV weakens the immune system of an infected individual • What is the main difference between the treatment of viral STDs and the treatment of bacterial STDs. • List three symptoms of genital herpes • How can you best protect yourself from contracting a sexually transmitted disease?