Human Reproduction Flashcards
What is human reproduction?
any form of sexual reproduction resulting in human fertilization, typically involving sexual intercourse between a man and a woman
Different stages of human reproduction…
- ovulation
- copulation
- fertilisation
- cell division
- implantation
- development of the embryo
- birth
- ovulation…
an egg cell is released from one of the ovaries
- copulation…
a man and woman have sexual intercourse
the man’s penis becomes erect and is put into the woman’s vagina.
When the man ejaculates, semen containing millions of sperm are released into the woman’s vagina.
The sperm start to swim through the cervix, into the uterus and onto the oviducts (tubes which carry egg cells from the ovaries to the uterus)
- fertilisation…
When a sperm cell enters an egg cell, the nucleus of the sperm cell fuses with the nucleus of the egg cell to form a zygote (fertilised egg cell)
Fertilisation happens in the oviduct.
- cell division…
Cell division happens after the egg cell is fertilised.
The single-celled zygote makes a copy of itself, then splits into two identical cells, these two cells then divide again to form 4 cells, which divide to form 8 cells and so on to form a ball of identical cells in which then starts to form an embryo.
- implantation…
embryo implants or embeds itself in the lining of the uterus.
This happens about one week after fertilisation
- development of embryo…
zygote develops into an embryo (4 days to 9 weeks), then a foetus (9 weeks to birth). After about 40 weeks the foetus is ready to be born as a baby.
- birth…
process of bringing forth a child from the uterus, or womb when the baby is ready to be born.
How is the developing foetus protected?
Amniotic sac.
A thin-walled sac that surrounds the foetus during pregnancy.
The sac is filled with liquid made by the foetus (amniotic fluid) and the membrane that covers the foetal side of the placenta (amnion).
This protects the foetus from injury and bumping against the walls of the uterus
How does the developing foetus gets its nutrients and oxygen?
The placenta connects the maternal and foetal circulatory systems.
The placenta provides oxygen and nutrients from the mother to the growing foetus.
How does the developing foetus get rid of its waste products while it is in the uterus?
Waste products and carbon dioxide from the baby are sent back through the umbilical cord blood vessels and placenta to the mother’s circulation to be eliminated.
embryo…
After about 4 days, the cells in the ball of cells start to specialise into different types of cell.
It is now called an embryo until 9 weeks
fuse…
join together.
erection…
penis contains erectile tissue, which fills with blood during copulation.
This causes the penis to become hard so that it can be put into the woman’s vagina
