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8 Cards in this Set
- Front
- Back
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How are sperm attracted to an egg?
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by chemical signals
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What happens after a sperm breaks through the egg's layer of follicle cells?
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it binds to the zona pellucida, and proteases from the acrosome digest a path for the sperm in the acrosomal reaction
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What happens when the sperm gets through the zona pellucida and its membrane fuses with the egg's?
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the cortical reaction -- small vesicles called cortical granules move to and fuse with the egg's plasma membrane, making it hard so that no more sperm can enter
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Do the sperm and egg cell nuclei fuse together?
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No. They carry out mitosis to form a two-cell embryo.
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What two hormones secreted by the corpus luteum are needed during pregnancy?
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estrogen and progesterone
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What hormone keeps the corpus luteum from degenerating and where does it come from?
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The embryo secretes HCG (human chorionic gonadotrophin) after implanting in the uterus wall. HCG makes the corpus luteum grow and keep secreting estrogen and progesterone. The corpus luteum starts to degenerate during the middle of pregnancy, by when the placenta is secreting the two hormones.
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Where are the fetal blood and the maternal blood in the placental villi?
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The fetal blood flows through capillaries in the villi, while the maternal blood flows through inter-villous spaces. The fetal blood never mixes with maternal blood.
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What diffuses into the fetal blood from maternal blood and what diffuses out?
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O2, glucose, lipids, water, mineral, vitamins, antibodies, and hormones diffuse in, and CO2, urea, hormones, and water diffuse out
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