Embryology 1 Flashcards
What are the three phases of pregnancy?
What are the cells that produce the sperm cells and the ova?
Spermatogonia Oogonia
Where are the Spermatogonium Oogonium found?
Gonads
What is the contents of a sperm cell?
22 chromosomes, 1 X, or 1 Y
What is the contents of an ovum?
(22+X) and 3 polar bodies
What fuses to from the zygote?
(pro)Nucleus of sperm enters and fuses with the (pro)nucleus of ovum to give a diploid cell called the ZYGOTE
What part of the sperm enters the ovum?
Only the nucleus. The rest of the cell is left behind
What happens during week one of pre-embryonic phase?
Why are zygotes always unique?
No two sperm/ova are the same
Which parent is mitochondrial disease inherited from?
Mother
What is a solid ball of cells formed from a zygote called?
A morula
What day is a blastocyst formed?
Day 5/6 of pre-embryonic phase
Why is the blastocystic cavity formed?
•As the number (and size) of cells increase, getting nutrition to the central core of cells starts becoming difficult
How is the blastocystic cavity formed?
- Cells accumulate at one end to form an inner cell mass.
- The outer lining of cells is called the trophoblast.
How long does the first cell division take?
36 hours
What happens on day 5/6?
The blastula has formed and this has reached the uterine cavity ready to implant in it.
What is required for the the dividing zygote/ morula/ blastocyst fallopian tube to move and reach the uterine cavity?
requires healthy ciliated epithelium
When is ectopic pregnancy likely to occur?
Could occur if cilia function is abnormal, pregnancy occurs in the uterine tube. Complications inculde rupturing of the uterine tubes.
What is the endometrium?
The mucous membrane lining the uterus, which thickens during the menstrual cycle in preparation for possible implantation of an embryo.
When does the placenta start to develop?
This may start by day 6 of 1st week, when implantation occurs in the uterine endometrial layer
What is the structure called that ater forms the embryo?
Bilaminar disc
What structures do we see start to form at week 2?
•Sacs, membranes and cord to nourish the human conceptus (baby) start to form
What is the role of the chorion?
Burrowing
What cells are initially called to trophoblasts?
Cells that form the outer cell mass
