1. Human Reproduction Influenced by gene expression, hormones, and the environment

2. Male Reproductive System Testes  produce sperm cells and testosterone – the hormone associated with male secondary sex characteristics and the production of sperm ex: body hair, deep voice, increased muscle mass Structures that produce fluid and nutrients needed for proper function and delivery of gametes (sperm) to the male reproductive system Structures that produce fluid and nutrients needed for proper function and delivery of gametes (sperm) to the male reproductive system

3. Male Anatomy 2 paired testes hang outside the body in a sac of skin called the scrotum (this keeps the temperature slightly lower than inside the body and allows for the survival of sperm.) Testes initially develop inside the body and descend about 1 month before birth – failure to descend can lead to an increased risk of cancer so it must be surgically brought down Testes initially develop inside the body and descend about 1 month before birth – failure to descend can lead to an increased risk of cancer so it must be surgically brought down

4. Each testis is composed of hundreds of small tubules where the sperm are made Sperm are made continually throughout life though the number of healthy sperm decreases as one ages Sperm are made continually throughout life though the number of healthy sperm decreases as one ages

5. From the testes the sperm move into an epididymis – storage tubule – where they mature Next they move into the Vas Deferens – long tube that goes up into the body Empties into the urethra which passes through the penis and delivers sperm to the female

6. 3 structures that secrete fluid to nourish and transport sperm. This fluid + sperm = Semen Involuntary contractions force semen through the urethra and outside the body = ejaculation Muscle closes bladder to urethra so urine does not exit with semen

7. Female Reproductive System Internal fertilization in oviduct Internal development in uterus Production of sex cells in ovaries Provide essential nutrients to embryo and fetus through the placenta Provide nutrition through milk to the newborn

8. Gonads are ovaries  produce eggs, hormones (estrogen and progesterone) ESTROGEN – determines female sex characteristics: breasts, fat distribution, regulate menstrual cycle PROGESTERONE – maintains uterus during pregnancy

9. Female Anatomy Ovaries (2) 4cm X 2cm in lower abdomen – each contains small sacs known as follicles that hold an egg (~500 in mature ovary) When egg matures follicle ruptures (1 each month) and egg pops out (ovulation) Egg enters tubes known as oviducts (egg ducts) or fallopian tubes – it lives ~24-48 hours and this is where is can be fertilized

10. Leads to uterus – muscular organ where embryo develops into fetus. Where embryo sinks into wall – Placenta forms which provides nutrients to fetus

11. Delivery – Uterus contracts and pushes through cervix  opening of uterus  to the vagina (birth canal) Urinary system is totally separate – urethra opens anterior to the vagina

12. At sexual maturity (puberty) females begin menstrual cycle ~ 28 days with ovulation occurring at day 14  timing controlled by 2 hormones from the pituitary and 2 hormones from ovaries The rise and fall of hormones regulates the cycle (variable lengths) Menstrual cycle starts around 10-14 years and ends by ~ 50- 55 at Menopause

13. 4 Stages of the Menstrual Cycle 1.Follicle Stage – Pituitary  makes FSH (follicle stimulating hormone)  stimulates follicle in ovary to get egg ready - Follicle makes estrogen  starts to get uterine wall thicker in case of pregnancy (lasts till day 14) 2. Ovulation – Pituitary  LH (lutenizing hormone)  Ruptures follicle (ovulation)  egg is out of follicle

14. 4 Stages of the Menstrual Cycle 3. Corpus Luteum Stage – Follicle turns yellow  corpus luteum produces progesterone – develops in uterus 4. Menstruation – If fertilization does not occur – corpus luteum disappears  no progesterone  lining of the uterine walls sheds – blood and wall is shed and known as menstruation (~5 days)

16. Human Development Pregnancy = gestation  continues in the uterus (lasts ~9 months or 40 weeks) embryo  2 months “Fetus” 1 st part of pregnancy = development of organs occurs in the first 3 months

17. Things can go wrong that affect the development of the fetus - Faults in the genes or DNA - Xrays - STD’s - Environmental factors: a) alcohol – FAS (fetal alcohol syndrome) b) drugs – drug addicted babies c) smoking – low birth weight babies d) poor diet in mother e) infections – especially German Measles and AIDS can cause defects

18. Mother needs Pre-Natal care and should avoid harmful things that can cause birth defects - After birth – development and differentiation and growth continue until adulthood when organs are age, weaken, and die

19. Process of Birth Labor = rhythmic contractions of uterus 1. cervix opens (.1-10 cm) 2. head delivered first 3. amniotic fluid comes out 4. umbilical cord cut 5. Placenta delivered

20. Reproductive Technology Birth Control = Contraception  methods of preventing pregnancy 1. pill – disrupts hormones 2. diaphragm or condom – barrier method and prevents STD’s 3. surgical vasectomy or hysterectomy 4. ABSTINENCE – only 100% affective form of birth control

21. Reproductive Technology Ecology – 1. Build up endangered species – transplant embryos into different animals Medicine – 1. Hormone prescription to help women who can’t get pregnant (fertility drugs) 2. Artificial insemination 3. In-vitro fertilization – test tube embryos  implanted 4. Ultrasound and mini camera – view reproductive organs 5. Amniocentesis – needle to remove cells from fluid around baby – analyze cells for genetic problems