4. the placenta Flashcards
Which three organs does the placenta take the role of in the foetus?
Kidney, GIT and lungs.
The DNA of the placenta is comprised primarily of which individual?
The foetus.
What are the two layers the trophoblast splits into during early embryo development? How are they different?
- syncytiotrophoblast - outer layer in contact with maternal blood. involved in hormone secretion.
- cytotrophoblast - inner layer with many specialised functions.
Which artery mainly supply the uterus?
Uterine artery which is a branch of the internal iliac artery.
Describe the characteristics of the umbilical cord.
Has two arteries (deoxygenated blood) going towards the placenta and one vein (oxygenated blood) coming from the placenta.
What does placental examination post-delivery involve?
Examine the cotyledons, there should be 15-20 separations to ensure there is not any missing in the uterus.
Which drugs should we avoided during pregnancy and why?
Anti-epileptic drugs e.g. sodium valproate. Baby may have developmental issues and physical disabilities.
Which molecules diffuse across the placenta via passive diffusion? Why?
Steroids and fatty acids. Bc they’re fat soluble, quite small and unionised.
Which molecules travel across the placenta via facilitated diffusion? Why?
Glucose, needs GLUT1 and a glucose diffusion gradient. It is insulin independent.
Which molecules travel across the placenta via active transport?
Amino acids and Fe & Ca ions.
Which molecules travel across the placenta via pino/endocytosis?
Immunoglobulins such as IgG.
Give two ways foetal O2 carriage is aided.
- Increased affinity for O2 due to foetal haemoglobin.
- polycythemia which is an increased RBC conce.
How is O2 transfer mediated between foetus and mother?
Bohr Effect.
What is placenta praevia?
When the placenta covers the cervix opening which could prevent a natural birth.
What is pre-eclampsia?
The placental blood vessels fail to develop normally. This causes inadequate perfusion. This causes vasoconstriction in the mother therefore resulting in high BP during pregnancy. If left untreated, it could lead to seizures. The problems arise from the placenta.
