Placenta Flashcards
What are some features of the placenta
- Extensive exposure of maternal blood to non-maternal tissue (the trophoblast)
- Gaseous exchange, transport of nutrients, excretion, hormone and protein
What carries the oxygenated and deoxygenated blood.
Umbilical arteries - Carry deoxygenated blood to the placental
Umbilical veins - Carry oxygenated blood to the foetus
What produces HCG
The syncitiotrophoblast
What is the function of HCG
It maintains the Corpus Luteum, which in turn secretes progesterone.
What does the placenta produce in the second trimester
Progesterone and Estriol which stimulates uterine growth and mammary gland development.
What is the decidual reaction
Consists of:
- Increased vascular permeability
- Oedema in intercellular matrix
- Swelling of stroma cells and accumulation of glycogen granules
- Progressive sprouting and ingrowth of capillaries
What induces the decidula reaction?
Progesterone
How does maternal blood get into the trophoblast system?
The syncytiotrophoblast erodes the endothelial lining of maternal sinusoids
What happens on day 13
The cytotrophoblast begins to proliferate and penetrate the syncytiotrophoblast forming primary villi. Uteroplacental circulation begins.
What does the umbilical cord consist of?
- A vein that carries oxygenated blood to the foetus
- Two arteries that carry deoxygenated blood to the placenta
- Wharton’s jelly
What is replaced due to the formation of the umbilical cord?
The yolk sac
Where are the decidua basalis and chorion frondosum, and what are they
in notes
Decidua basalis - Maternal component
Chorion frondosum - Fetal component
Describe the structure of the placenta
in book
When do primary chorionic villi become secondary chorionic villi and tertiary chorionic villi
When they acquire mesenchymal cores they are secondary and then when capillaries develop they’re tertiary.
What are the four types of placental pathologies? and describe them
Placenta accrete - the placenta implants too deeply all the way to the muscle.
Placenta Praevia - When the placenta is to close to or blocks the cervix
Placental abruption - When the placental lining separates form the mother prior to birth
Pre-eclampsia - Abnormal development of the placenta leads to poor placental perfusion
