Placental Function

Question 1

What are the main functions of the placenta?

Answer 1

To replace function of adult:
	Lungs (delivery of gases)
	Gut (delivery of nutrients)
	Kidney (excretion of waste products)
	Liver (storage/reservoir of energy)
Endocrine (placental derived hormones)
Protective (toxic substances)

Question 2

Does the placenta grow as much as the fetus?

Why?

Answer 2

No, this means that placental efficiency must increase with gestation to support fetal growth
Answer lies in the exponential increase in cotyledonary microvascular density (fetal side of placenta) which matches, and is highly related, to the increase in fetal growth

Question 3

Diffusion of substances across the placenta is …………

Answer 3

Passive

Question 4

Which type of foetal-maternal interface is most efficent?

Answer 4

Epitheliochorial is least and haemochorial is the most

Question 5

The polarity of the fetal extracellular fluid is ……………. compared to the maternal in order to aid transport

Answer 5

More negative

Question 6

What are the primary glucose transporters?

Answer 6

GLUT1 and then later GLUT3

Question 7

Reduced amino acid transport is associated with ……………….

Answer 7

Growth retardation

Question 8

Anastomosis of which vessels most commonly produces freemartins?

Answer 8

Anastomosis of allantoic vessels (90% of cases)

Usually a single chorionic cavity

Question 9

In sheep what happens if the allantochorions of adjacent fetuses to fuse?
Can this happen to cats and dogs?

Answer 9

They share a single chorionic cavity

No as their allantochorions is relatively avascular

Question 10

What is IUGR?

Answer 10

Impaired growth and development of the mammalian embryo/fetus or its organs during pregnancy

Question 11

What can cause IGUR?

Answer 11

Maternal nutrition and/or nutrient imbalance
Maternal intestinal malabsorption
Ingestion of toxic substances
Environmental temperature and stress
Disturbances in maternal or fetal metabolic and homeostatic mechanisms
Insufficiency or dysfunction of the uterus endometrium, or placenta
Poor management
Multiple fetuses impact on the placenta

Overfeeding can also cause IUGR

Question 12

What is the problem with twinning?

Answer 12

Cows: reduces fetal growth and calf birth weight
Sheep: increased fetal number results in relative placental insufficiency and low birth weights
Mares: Reduced surface area for placental nutrient exchange.

Question 13

What is pre-eclampsia?

Answer 13

Not enough invasive action of the cells so the mother needs to work harder to supply. The foetus heart works harder