BL - Embryology Flashcards
What are the tubes called that connect the ovaries with the uterus?
Fallopian tubes
Briefly explain the process of oogenesis.
- oogonium splits into another oogonium and a primary oocyte
- primary oocyte splits into 1st polar body and secondary oocyte
- 1st polar body splits to form two more polar bodies (polar body still undergoes mitosis despite having no role)
- secondary oocyte splits to form secondary polar body and ovum
Where does fertilisation take place usually?
The ampullary region of the Fallopian tube
True or false - sperm must be introduced into the female reproductive tract within five days before ovulation?
True. Sperm are viable for five days, but secondary oocytes are only viable for 12-24 hours.
What is capacitation?
When the tail of the sperm moves faster causing the plasma membrane to alter.
Why is semen not rejected by the body?
The body only develops antigens for semen if it is exposed to the blood supply. This means that there are no antibodies for its antigens.
What is the difference between embryonic age and gestational age?
Embryonic age is time since fertilisation, while gestational age is time since last menstruation.
What is the “germinal stage”?
Time from fertilisation to the end of the second week.
What is the “embryonic period”?
Time from third week to end of eighth week
What is the “foetal period”?
Beginning of ninth week to birth at 38 weeks.
What is the zona pellucida?
A ‘shell’ that surrounds the egg, preventing it from adhering to the oviduct. It must be lost before the blastocyst can implant.
What does the fertilised egg form when it reaches the 16-celled stage?
A morula
What forms after the morula?
Blastocyst
Where does implantation usually occur?
The posterior wall of the upper part of the body of the uterus.
What is an ectopic pregnancy?
This occurs when the blastocyst implants in the wrong place, eg the fallopian tube.