B5: Fertilisation and the Development of the Foetus Flashcards
What is the scientific term for reproductive cells (egg and sperm cells)?
Gametes
The male gametes are…
Sperm cells
The female gamete is the
Egg cell (Ovum)
When an egg and sperm nuclei fuse together, we call it…
……fertilisation
The oviducts are lined with cells lined with small hair like structures called…
Cilia
What is the function of the cilia that line the oviducts?
They waft the egg released by the ovary along to the uterus.
What happens after fertilisation?
- The fertilised egg divides into a ball of cells called an embryo. 2. The embryo attaches to the lining of the uterus and begins to develop into a baby. This is called implantation.
How often is an egg released from an ovary?
Once a month
Where does fertilisation occur?
The Oviduct
Why can only one sperm fertilise the egg?
The membrane of the egg (ovum) thickens when the first sperm has penetrated.
What is the scientific name for an egg that has been fertilised?
A zygote
What is the function of the umbilical cord?
It connects the fetus to the placenta.
In mammals, the time spent in the uterus during development is called…
….gestation
What effect can smoking have on an unborn baby?
Premature birthLow birth weight
What is the function of the fluid sac (amniotic sac)?
It acts as a shock absorber, protecting the foetus from any bumps.
What is the function of a placenta?
* An organ where substance pass between the mother’s blood and the fetus’s blood. * It acts as a barrier, which stops infections and harmful substances reaching the foetus.
What effect can alcohol have on an unborn baby?
Poor brain development
How long is the human gestation period?
9 months (40 weeks)
Does the blood of mother and fetus mix when it is developing in the uterus?
NO - but useful substances like nutrients and oxygen can pass from mother to baby through the placenta.
When a fertilised egg (zygote) divides into a ball of cells, we call the ball of cells an…
embryo
The menstrual cycle lasts for…
28 days (approximately)
What happens on day 1 of the menstrual cycle?
Bleeding as the lining of the uterus breaks down.
What is the function of the uterus lining?
To provide a spongy, blood rich layer for embryo implantation.
What happens on day 14 of the menstrual cycle?
Ovulation - an egg is released from one of the ovaries.
What happens if a sperm cell does not meet the egg after ovulation has happened?
The lining of the uterus breaks down and the menstrual cycle starts again from day 1.
