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Unit 14 Human Reproduction. This is NOT sex education. Having sex can cause disease called STD ( s exually t ransmitted d isease) HIV infection Genital herpes Syphilis Gonorrhea. Herpes. Syphilis. Gonorrhea. Safe Sex. _____ ______. Human Reproduction Questions.
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This is NOT sex education • Having sex can cause disease called STD (sexually transmitted disease) • HIV infection • Genital herpes • Syphilis • Gonorrhea
Safe Sex • _____ ______
Human Reproduction Questions • Q. Can the first time someone has sex cause pregnancy? • Q. Which is smaller a sperm cell or an egg? • Q. How do sperm swim? Cilia? Villi? Flagella?
Human Reproductive SystemFemale • Oogenesis- egg production • Four eggs are created per month yet only one survives • Three Polar bodies are created • This causes chromosomal shedding • Cytokinesis is lopped sided in oogenesis
Human Reproductive System- Male • Meiosis produces sperm in the testicles • Spermatogenesis has equal cytokinesis • The two testicles are in a sac outside the body called the scrotum • The testicles move with temperature • Sperm meiosis takes place below body temperature (Jockey shorts are anti-spermatogenic)
Path of Sperm • 1. Manufactured in the seminiferous tubules of the two testes • 2. Epididymis (Epi, did I miss?)- long coiled tube where sperm matures • 3. Vas deferens where sperm is stored • Ejaculation = sperm is released from the vas deferens to the urethra which carries the sperm through the penis
Path of an Egg • 1. Egg is produced in the ovary • 2. The ovary releases an egg through the process called ovulation • 3. The egg usually finds it way up the fallopian tube and is carried to the uterus for implanting • Fertilization can occur anywhere along this path
EGGS • Q. Are all eggs formed at the birth of the female? • A. Sort of. A female’s ovaries contain about 2 million oocytes at birth, all have begun meiosis and are stopped in prophase these are called primary oocytes • Only a few primary oocytes go into full mitosis • About 400 of the 2 million oocytes become OVA, mature eggs
Human Reproduction • Meiosis produces 700,000,000 sperm per day and one egg per month • Egg meets sperm to form a single cell called a Zygote • The zygote becomes an embryo • The embryo becomes a fetus • After nine months (266 days) the fetus becomes a child
There only a small difference between man and females • Everyone starts out a as female • In the tenth week the “Y” chromosome on sperm causes a male, without the “Y” the embryo becomes female • Internally- we are set up to go either way • Indifferent gonads can become ovaries or testicles
Twins • Identical = same egg and sperm • Fraternal = separate eggs, separate sperms • Can fraternal twins have separate fathers? Be of different races? • What can happen if a identical twin egg doesn’t separate totally?