Reproductive System: conception Flashcards
Fertilisation and implantation (18 cards)
Where allows sperm to swim?
Their tails
Where do sperm travel to?
Through the cervix into the uterus/womb
Where do the sperm that do survive go?
The fallopian tubes
How long can sperm survive until an egg arrives?
Up to 3 days
What part of the sperm falls off when fertilisation occurs?
Tail
What happens to the sperm’s head/nucleus during fertilisation?
It will fuse with the ovum nucleus. The ovum then gains a hardened wall to keep out other sperms
Implantation
The process in which a fertilised egg is attached to the uterus lining, leading to pregnancy
Ova
Eggs
Where are ova developing?
In follicles (sacs) in an ovary
Implantation: Part 1 - ova
Several ova are developing in follicles (sacs) in the ovary. Ovulation occurs and the ovum nucleus then splits in two. The smaller part (polar body) of the ovum nucleus moves to the ovum shell.
Implantation: Part 2 - ovum shell
The nucleus splits again, and a second polar body moves to the ovum shell. The sperm now fuses with the main nucleus to fertilise the egg.
The fertilised egg continues along the fallopian tube toward the uterus
Implantation: Part 3 - eggs splitting
The egg splits into 2 cells some 30hrs after being fertilised. The two cells split again forming 4 cells about 20hrs later. These double and redouble
Implantation: Part 4 - morulus
The morulus (ball of cells) reaches the uterus 3-4 days after fertilisation. Fluid then appears within the morulus
Implantation: Part 5 - embryo
The fluid within the morulus separates cells into outer and inner groups, respective origins of the embryo + placenta (source of nourishment).
The blastocyst now loses its outer shell and lodges into the uterus wall
Smaller part of the ovum:
Polar body
Mature ovum:
Egg
Morulus
Ball of cells formed during implantation
Blastocyst
Pin-head size complex that was previously the morulus
