Placenta Flashcards
What are the parts of the placenta?
What are the properties of the placenta?
- Discoidal
- Maternal aspect is divided into 15-20 cotyledons
What are the properties of placental blood?
- Enters cotyledons via 80-10p spiral aa and leaves via uterine vv tributaries
- Maternal blood space surrounds villus trees and holds 150ml blood
- Foetal blood is separated from maternal blood
What is placental abruption?
- Placenta peels away from uterine wall before delivery
- Can cause poor foetal growth as deprived of oxygen and nutrients
- Can cause maternal bleeding
- Can cause premature and stillbirth
- Occurs in 1/100 pregnancies
What is placenta previa?
- Low-lying placenta which covers most or all of cervix opening
- Block babies exit from uterus
- Potential tearing of blood vessels connecting to placenta, causing bleeding during labour
- Can cause premature birth
- Occurs in 1/200 pregnancies
What is placenta accreta?
- Placenta implants too deeply and firmly to uterine wall
- May cause excessive bleeding during delivery
- Occurs in 1/2500 births
What are some placenta-mediated conditions?
- IUGR
- Pre-eclampsia
- Diabetic pregnancy (cause malformation)
- Smokers pregnancy (cause small size)
- Pregnancy at altitude
What does the intraembryonic coelom form?
Pericardial cavity
Pleural cavity
Peritoneal cavity
What are the 3 longitudinal columns formed by the intraembryonic mesoderm?
Paraxial
Intermediate
Lateral plate
What does the prochordal plate form?
What does the neural tube form?
What does the cloacal plate form?
Mouth
Brain and spinal cord
Anus
What does the medial, intermediate and lateral somites form?
Skeleton
Muscle
Skin
What does the somatopleuric mesoderma and sphlanchopleuric mesoderm form?
Striated muscle
Gut smooth muscle
What is the chorion composed of?
Trophoblast and extraembryonic mesoderm
