Reproduction in Humans Flashcards
Whats sexual reproduction?
The sperm must move to the egg and fuse with it.
Whats asexual reproduction?
A mode of reproduction in which a new offspring is produced by a single parent.
How are gametes produced?
Are produced when the cells in these organs divide, these cells divide by meiosis.
Meiosis produces cells that are not genetically identical and have only half the number of chromosomes as the original cell.
Whats semen?
Sperm mixed with seminal vesicles.
What are the steps of intercourse?
1) During intercourse, millions of sperm enter the vagina. Millions of them die due to the acidic enviorment.
2) Next the sperm must pass through the cervix. The cervix is opened for a few days while the woman ovulates.
4) Next half he sperm head towards the empty fallopian tube, while the other half head towards the tube containing the unfertilized egg.
5) Now only a few thousand remain. Inside the fallopian tube the cilia push the egg towards the uterus.
6) Eventually a single sperm will reach the egg and fertilize it.
Whats placenta?
When the zygote begins to develop into an embryo, the embryo develops a placenta, which will allow the embryo to obtain O2 and nutrients from the mothers blood and also allows the embryo to get rid of waste products such as urea and CO2.
Whats amniotic fluid?
Protects the developing embryo against sudden movements and bumps.
What are the 3 stages of birthing a child?
1) Dilation of the cervix. The cervix gets wider to allow the baby to pass through. The muscles of the uterus contract strongly and the amniotic fluid escapes.
2) Delivering of the baby. Strong muscle contraction of the uterus push the baby’s head through the cervix and then through the vagina to the outside world.
3) Delivery of the afterbirth. After the baby’s born, the uterus continues to contract and pushes the placenta out, together with the membranes that surround the baby.
What triggers puberty?
Hormones released by the pituitary gland, called follicle stimulating hormone (FSH) and luteinising hormone (LH).
In boys, what does FSH and LH do?
In boys, FSH simulates sperm production, while LH instructs the testes to secrete testosterone.
Whats the menstrual cycle?
the monthly series of changes a woman’s body goes through in preparation for the possibility of pregnancy. Each month, one of the ovaries releases an egg, a process called ovulation. At the same time, hormonal changes prepare the uterus for pregnancy.
Whats a period?
If the egg isn’t fertilized, the lining of the uterus is lost from the woman’s body as the flow of blood and cells of the lining, called a period.
