Placental and Fetal Flashcards
What happens during the first trimester to spiral arteries?
They become blocked. No maternal blood flowing so foetus rely on nutritional material in spaces between fetal tissue and maternal tissue.
What sort of placenta is found in humans?
Discoid placenta (placenta arranged in a circular shape).
Why do humans have a discoid placenta?
Increases in oxidative stress, increase in apoptosis and a decrease in proliferation result in placenta regressing.
When do the spinal arteries unplug?
During the second trimester.
Give 2 functions of the placenta.
Respiratory organ. Nutrient transfer. Excretion of fetal waste. Hormone synthesis.
What is the difference between the cytotrophoblast and the syncytiotrophoblast.
Cytotrophoblasts contain mononucleated cells. Syncytiotrophoblasts contain multinucleated cells.
What is the decida basalis?
Area of endometrium between the implanted chorionic vesicle and the myometrium, which becomes the maternal part of the placenta.
Empty spaces of the primary villi are known as…
Lacunae.
The syncytiotrophoblast penetrate what to develop the placenta.
Decida basalis
Define macrosomia.
Overweight at birth. Causes problems during labour, and increases the risk of a still birth.
How many arteries and veins are found within the umbilical cord?
2 arteries. 1 vein.
Are fetal arteries deoxygenated or oxygenated?
De-oxygenated.
Are fetal veins deoxygenated or oxygenated?
Oxygenated.
What are the three structures of the umbilical cord?
Body stalk. Vitelline duct. Allantois.
The endoderm develops the gut tube, which divides into 3 layers. What are these 3 layers?
Foregut. Mindgut. Hindgut.
What is the Vitelline duct? :
Open connection between the yolk sac, midgut at week 3.
What is the Allantois?
Small hindgut outpocketing that grows into umbilical cord at week 3.
Give 2 contents of the amniotic fluid.
Urine. Amniotic membrane secretions. Fetal lung secretions. Salivary secretions. Fetal epithelial cells.
When do uterine spiral arteries do?
They play a vital role in supplying nutrients to the placenta and fetus from the second trimester.
Give 2 adaptations of a fetal circulatory system.
Umbilical vein and artery. Ductus venosus. Foramen ovule. Ductus artiosus.
Give 2 differences between pre and postnatal circulation.
Prescence of placental circulation. Lack of circulation to lungs.
What is a ductus venosus?
It shunts a portion of the left umbilical vein blood flow directly to the inferior vena cava. Thus, it allows oxygenated blood from the placenta to bypass the liver.
What is a foramen ovale?
Hole between right and left atria. Allows blood to bypasss pulmonary circulation.
What is a ductus arteriosus?
Shunt connecting the pulmonary artery to the aorta, therefore blood can ignore the lungs (inactive).
Name 1 of the 3 changes at delivery.
Closure of the foramen ovale, ductus arteriosus and ductus venosus.
