3) Placental Metabolism Flashcards Preview

Nutrition through life Val > 3) Placental Metabolism > Flashcards

Flashcards in 3) Placental Metabolism Deck (145)
Loading flashcards...
1

When does the fastest growth of the placenta occur? Why?

- During the first half of pregnancy
- To prepare for the fetal growth spurt during the second half of pregnancy

2

What is the placenta?

The interface between the microcirculatory systems of the mother and fetus

3

What are functions of the placenta?

- Exchange of nutrients, respiratory gases, and metabolic waste
- Protection of the fetus from xenobiotics
- Acting as a source of hormones

4

When is there mixing of the maternal and fetal blood?

- There is NEVER any direct mixing of the maternal and fetal blood
- The placenta is composed of a maternal and fetal portion

5

Where does the majority of amniotic fluid come from?

The maternal blood via diffusion from the intervillus spaces of the placenta

6

What are functions of amniotic fluid?

- Acts as a shock absorber
- Prevents desiccation of the fetus
- Provides room for fetal movements
- Assists in body temperature regulation

7

The ________ plate forms the fetal surface of the placenta.

chorionic

8

______________ are cells from the placenta that connect the mother and fetus.

Cytotrophoblasts

9

What components form the large area for exchange of fetal and maternal material?

- Cytotrophoblastic shell
- Anchoring villi

10

Where does the exchange between maternal and fetal material occur?

Within the intervillus spaces, as maternal blood flows around the villi

11

What is the major functioning unit of the placenta?

Chorionic villus

12

What placental defects do IUGR infants display?

They have microscopically less branching of the villi

13

What is the function of the villi within the placenta?

Enhances the surface area, allowing for greater exchange of gases and nutrients

14

The placenta uses 50% of _______ and 65% of _______ from the maternal blood supply.

oxygen
glucose

15

What substances does the placenta synthesize for fetal use?

- Glycogen
- Lactate
- Cholesterol

16

What substances cannot cross the placental membrane?

Compounds possessing a large molecular weight

17

What substances are transported across the placental membrane via passive diffusion?

- Oxygen and carbon dioxide
- Fatty acids
- Steroids
- Electrolytes
- Fat-soluble vitamins

18

How does fetal hemoglobin differ from regular hemoglobin?

Fetal hemoglobin has a greater binding capacity for oxygen

19

How are fatty acids transported through the placental membrane?

- Passive diffusion
- Carrier-mediated transport for long-chain FAs (enhancement of PUFA transport)
- The fetus depends on a supply of EFAs

20

Of the substances that are transported via passive diffusion, there is a poor transfer of which one?

Fat-soluble vitamins

21

How are sugars transported through the placental membrane?

Carrier-mediated facilitated diffusion

22

What is the importance of glucose transporters within the placenta?

- Glycation is a mechanism of teratogenesis
- Glucose transporters are used to protect the fetus from high glucose levels

23

If a mother experiences hyperglycemia, is a fetus exposed to a hyperglycemic environment as well? Why or why not?

- No, the fetus experiences a lower glucose level
- Because of the use of glucose transporters

24

What substances require energy-dependent active transporters to cross the placental membrane?

- Amino acids
- Certain cations
- Water-soluble vitamins

25

What do iron and folate require to cross the placental membrane?

Pinocytosis

26

What do water and solutes use to cross the placental membrane?

Solvent drag

27

The fetal size is proportional to the _______ size.

placental

28

How may maternal malnutrition, such as iron deficiency, affect placental size and fetal growth retardation?

- Reduced blood volume expansion
- Decreases cardiac output and placental blood flow
- Decrease in placental size, reduced nutrient transfer, and subsequent fetal growth retardation

29

What conditions may decrease uterine blood flow and affect placental transport?

- Hypotension
- Renal disease
- Placental infarction

30

During the third trimester, how does the fetal weight and the placental weight change?

- The fetal weight more than doubles at the last 10 weeks
- The placental weight only increases by 50%