Human Reproduction

HumanReproductionSimilarities / DifferencesDevelop very similar structures of sex glands Two genital tubesManufacture the hormones of the other sex. Hormones of one sex are often used to treat illness in the other sex. Both sexes have reproductive organs call GENITALS or GENITALIA, designed for the purpose of intercourse and conception.Only the female has organs for pregnancy and childbirth.

Human Reproduction TimelineMale Time Line:InfancyErections begin

Ages 11-14Secondary sex characteristics appear

Ages 13-16Sperm produced in adult amounts (puberty)

Late teensPeak sexual urges for boys

Throughout life if good health is present, there is the sex urge and ability to father children.

Female Time Line:

Ages 9-12Secondary sex characteristics appear

Ages 11-14Menstrual cycle begins

Late 20-30sPeak sexual urges

Ages 45-55menopause (cycle stops, but sex urge continues)

FertilizationDuring sexual intercourse (between a husband and wife) the penis becomes erect for the transfer of sperm into the vagina.After intercourse, the sperm cells swim through the female reproductive tract and enter the oviducts.If they meet with an egg in the oviduct, the egg and sperm cell may unite.The fusion of a sperm cell nucleus and an egg cell nucleus is known as fertilizationA fertilized egg is known as a zygote.

FertilizationFertilization generally occurs when the egg is in the upper portion of the oviduct.If the egg is not fertilized within about 24 hours after ovulation, it breaks down and disappears.Cleavage of the fertilized egg begins while the egg is still in the oviduct.Six to ten days later, the resulting embryo may become implanted (attached) in the lining of the uterus.

Swimming for your lifeA sperm is a tiny package with a big responsibility to fertilize the egg and create a human life. So that tiny package is loaded with gear for its important journey.

A few facts:Daily sperm production by a healthy man:10 million to 50 millionContents of average ejaculation:50 million sperm; 25 million moving; 20 million deformedMaturation: 72 daysAverage swimming speed of a sperm:8 inches per hourSurvival time in a woman: 2 to 7 daysEjaculation

Fertilization

FertilizationIf more than one egg is released and fertilized at the same time, multiple births may occur.Fraternal twins develop when two eggs are released at one time and each egg is fertilized by a different sperm.Identical twins develop from one zygote that separates in half early in cleavage.It is now possible for fertilization to take place outside the human body (in vitro). The fertilized egg is then implanted in the uterus so that development can occur.

Fertilization

Two Cells

Four Cells

16 CellsMorula Stage

Blastocyst Stage

ImplantationThe Human ZygotePrenatal DevelopmentWhen the fertilized egg arrives in the uterus, it implants itself in the thickened, spongy uterine wall.The gastrula forms, differentiation of cells and growth occurs.The developing embryonic membranes become part of the placenta and umbilical cord.After eight weeks of development the embryo is called the fetus.The period of time between the fertilization of the egg and the birth of the offspring is called gestationIn humans the gestation period is nine months or approximately 266 days.Human Gestation

3 Weeks

Human Gestation

3 Months

Summary of Human Developmenthttp://www.babycenter.com/fetal-development-inside-your-womb

During this time, it is essential that the expectant mother provide good prenatal care by eating nutritious foods, avoiding alcohol, tobacco, and drugs, and receiving proper medical attention regularly.Using tobacco, alcohol and drugs may cause low birth rates, premature births, Fetal Alcohol Syndrome as well as other birth defects.Prenatal Development

Postnatal DevelopmentFollowing birth, the placenta is discarded from the mothers body and the mother begins producing milk from mammary glands located in the breasts.The mothers breast milk is normally the best natural food for a newborn baby.

Pregnancy PreventionsVasectomyTubal Ligation

Teen fakes pregnancy for social experiment

High school senior Gabby Rodriguez tricked her peers into thinking she was pregnant.Gaby Rodriguez walked around Toppenish High School in Toppenish, Wash., for over six months with a swollen belly that gradually turned into a bulge the size of a basketball. Rodriguez revealed to her friends and teachers that she was pregnant. They were shocked that the high school senior with a 3.8 grade average was so irresponsible. Some whispered behind her back. Lots of mean things were said.Only a few people -- her mother, boyfriend, and the school principal -- knew Rodriguez was faking it. They knew she was conducting a social experiment.Yesterday, Rodriguez revealed that her pregnancy was a hoax by pulling a prosthetic belly out from under her shirt at a highly emotional all-school assembly titled: "Stereotypes, rumors and statistics." The Yakima Herald reports:Before taking off her fake baby belly in front of the entire student body, Gaby told her audience, "Many things were said about me. Many things traveled all the way back to me." Then, she asked several students and teachers to read statements from 3x5 cards, quotes people actually said about her during the course of her experiment. Her best friend, Saida Cortes, a 17-year-old senior who was sitting in the front row, read card No. 3: "Her attitude is changing, and it might be because of the baby or she was always this annoying and I never realized it." It grew quiet in the gym as more and more quotes were read aloud. Then Gaby dropped her bomb: "I'm fighting against those stereotypes and rumors because the reality is I'm not pregnant." Rodriguez received a standing ovation at the end of her speech. She had hoped to reveal the unfair treatment pregnant teens face, and she had successfully proven her point. She also wanted her peers to understand that being a pregnant teen is miserable--and so it's best to do everything possible to avoid the situation.Rodriguez is Hispanic, like 85 percent of the students at her school. When she learned about the high teen pregnancy rates among her peers, she wanted to do something and decided to take the issue on for her required senior project. At first she approached her mom. "I thought she was crazy," Juana Rodriguez told the Yakima Herald. "It didn't feel good." The school principal says that he was shocked when Rodriguez approached him. "I heard her out," principal Trevor Greene told the Herald. "I listened to her presentation, her proposal. And then I went through all the difficulties I foresaw to making this happen."But Rodriguez was persistent and in the end, Greene got approval from the district superintendent, who attended the assembly. "I wouldn't miss this," superintendent John Cerna told the Herald. "It's amazing that a young lady would take this challenge on. It was a well-kept secret.

Read more: http://www.sfgate.com/cgi-bin/blogs/sfmoms/detail?entry_id=87551#ixzz1MWcxluRm