Reproduction and Development
When are a woman’s egg cells developed? before birth
How many eggs will be released over a woman’s lifetime? about 400
In what structure does the egg develop? follicle
In what organ are the eggs held? ovaries
When do sperm begin to mature? at puberty
What is ovulation? release of egg from follicle
What leads to the uterus? fallopian tube
What helps move the egg to the uterus? cilia
How long does it take the egg to reach the uterus? 4 days
Where does fertilization usually occur? in the fallopian tubes
What happens to many sperm that enter the female reproductive tract? killed by acidic environment of vagina
Where are the chromosomes found in a sperm? the head
Where are the mitochondria found in a sperm? the tail
How many sperm fertilize one egg? one
How are identical twins related? genetically identical
How do fraternal twins develop? two eggs are fertilized by two sperm
When does cell differentiation begin? day 4
What happens if two sperm fertilize one egg? the body rejects the egg
When does the heart begin to beat? after the third week
What develops in week four? the beginnings of a head and face; the liver, the spinal cord
At what week are hands and feet recognizable? week 16
What surrounds the baby? amniotic fluid
How does the baby get nutrients and oxygen from its mother? through the placenta and umbilical cord
Does the mother’s blood mix with the baby’s blood? no
What gets through the villi of the placenta? oxygen, nutrients, alcohol, viruses, some drugs, antibodies