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reproduction in humans - Coggle Diagram
reproduction in humans
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menstrual cycle
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day 10 to 15
-fertile period
-ovulation takes place
=>the release of a mature egg into the oviduct
-uterine lining grows and thickens
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day 16 to 28
-progesterone produced to prevent ovulation and further development of eggs and to thicken and maintain uterine lining
-oestrogen production decreases
-if no fertilisation takes place, progesterone production stops and uterine lining will break down again
if fertilisation occurs:
-nuclei of egg fuses with nuclei of sperm and forms a zygote
-the zygote undergoes mitosis and forms a embryo
-ovary secretes oestrogen and progesterone to maintain and stimulate thickening of uterine lining to prepare for implantation of embryo
-finger-like projections on the embryo called villi help to implant the embryo into the uterine lining and eventually develops into the placenta
implantation
-sweeping action of cillia and peristaltic movements in the wall of the oviduct move the zygote forward towards the uterus
-it undergoes mitosis to form the embryo
-finger-like projections on the embryo called villi help to implant the embryo into the uterine lining and eventually develops into the placenta
placenta
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-allows oxygen and nutrients to diffuse from the mothers blood to the fetal blood
-allows metabolic waste/excretory substances to diffuse from fetal blood to mothers blood
-allows antibodies to diffuse from mothers blood to fetal blood
-produces oestrogen and progesteron
-fetal and mothers blood do not mix and the 2 blood capillaries are separated by a thin layer of tissue
-mothers blood pressure may kill the fetus
-blood groups might be different
=>agglutination can occur
-prevents pathogens from mothers blood to enter fetal blood
amniotic sac
-develops at the same time as placenta
-encloses embryo in fluid filled space known as amniotic cavity
-acts as a shock absorber to protect and cushion the fetus from injury
-allows fetal movement
-lubricates and reduces friction on vagina
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