Theme C lecture 6 Flashcards

1
Q

What is the function of the placenta?

A

It is the interface between the mother and the fetus responsible for exchange of gas and nutrients.

Placenta acts as a barrier

Immune function

Hormone production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How are nutrients and important gasses transmitted to the fetus?

A

Passive transport (diffusion)

Facilitated Diffusion

Active transport

Vesicular transport

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What stuff passes through the placenta via passive transport?

A

O2

Steroid hormones

Fetal waste - Uric acid, Urea, creatinine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What stuff passes through the placenta via active transport?

A

Amino acids

Folate

Micronutrients

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What stuff pass through the placenta via facilitated diffusion?

A

GLUT transporters transport glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What kind of molecules are transported by vesicular transport?

A

Large molecules (eg immunoglobulins)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How does the placenta act as a barrier?

A

Placenta metabolizes compounds as they pass through

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How does the placenta prevent the higher concentration of glucocorticoids in the mother from reaching the fetus?

A

Placenta expresses 11beta-HSD2 to convert active glucocorticoids into inactive metabolites

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What immune function does the placenta perform?

A

Placenta modulates maternal immune system to prevent rejection.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How does the placenta carry out its immune function?

A

Placenta secretes neurokinin B which binds to phosphocholines which parasites use to evade the immune system.

Placenta inhibits maternal T-cells via lymphocytic suppressors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Which antibodies cross the placenta and provide immunity for the fetus in early life?

A

IgG

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Can diseases pass through the placenta?

A

Several conditions can pass from the mother to the fetus via the placenta but not all.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the placenta’s endocrine function?

A

Produces Growth factors such as , Lactogen, IGF2, Prolactin, Growth Hormone

Produces progesterone which maintains endometrial lining, and prevents preterm labour.

Produces hunger regulating hormones to regulate mother’s eating. (leptin/ghrelin)

Many other factors are produced by the placenta which include VEGF (family of growth factors) and Corticotropin releasing hormone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the function of placental lactogen?

A

Regulates maternal insulin levels (increases fatty acids and glucose in the blood)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the function of placental progesterone?

A

Maintains endometrial lining, prevents preterm labor.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the function of leptin/ghrelin?

A

Peptide hormones that regulate maternal hunger/appetite

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Where does the placenta originally develop and how does this happen?

A

Placenta starts developing early in pregnancy and is important for implantation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Where is the embryological origin of the placenta?

A

Trophoblast forms the placenta as it thickens at the point it connects to the uterus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How does the placenta anchor the fetus to the wall of the uterus?

A

Trophoblasts invade through the endometrial wall and arteries are produced which provide blood supply to the placenta.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is placentation?

A

The development of specialised regions of fetal and maternal origin. When maternal cells and zygote-derived fetal cells come together within close proximity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

When does placentation complete itself during pregnancy in humans?

A

by the end of the 1st trimester of pregnancy.

*Placenta is the first organ to develop during pregnancy and the largest organ to be produced during gestation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is required for a normal pregnancy?

A

The placenta needs to develop at the correct position

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is placenta previa?

A

As the placenta grows it covers the cervix such that the fetus has no passage to pass out through which would cause the death of the mother.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How is placenta previa treated?

A

C-section is the best and safest method.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is placenta accrecia?

A

The fetus invades far beyond that depth that is considered normal and grows through the uterus and hurts structures such as the bladder.

When the placenta comes out it often causes severe blood loss because it tears much of the uterus and the bladder.

26
Q

What are some other conditions that influence placental development?

A

Pre-eclampsia

Gestational hypertension

Diabetes/Gestational diabetes

Over- undernutrition

Chronic stress

Asthma

27
Q

What effect do maternal conditions have on fetal development?

A

Maternal conditions can affect blood flow, nutrient availability, and endocrine function of the placenta causing altered fetal development.

28
Q

How are placentas classified?

A

classified based on the number of placental layers.

29
Q

Which maternal layer do humans have?

A

Hemochorial

30
Q

What happens at the hemochorial layer of the placenta?

A

Blood comes in from mother and forms a bath of blood in which the placental capillaries sit.

31
Q

What is the difference between epitheliochorial and hemochorial placentas?

A

Tree of capillaries interact and form complex networks of blood vessels to transfer material

Whereas in humans the fetal blood vessels sit in a bath of maternal blood.

32
Q

What animals have hemochorial placentas?

A

The hemochorial placentas are only really found in higher order primates and rodents

33
Q

What placental shape do humans have?

A

Diacoid placenta is what humans have

34
Q

What type of shapes can the placenta have?

A

Multicotyledonary (multiple implantation points sheep have it)

Diffuse (encapsulates entire fetus)

Discoid (humans and mice have it)

Zonary (ring around the fetus found in dogs and cats)

35
Q

What is a hemomonochorial placenta?

A

Hemomonochorial placenta is a placenta with a single type of layer between maternal and fetal blood.

36
Q

What are the layers between maternal and fetal blood in a hemodichorial placenta?

A

Hemodichorial placenta contains a layer of Syncytiotrophoblast and cytotrophoblast.

37
Q

What is the kind of layer found between the maternal and fetal blood in a hememonochorial placenta?

A

Syncytiotrophoblast

38
Q

What layers exist between maternal and fetal blood in a hemotrichorial placenta?

A

hemotrichorial placenta contains 2 layers of syncytiotrophoblast and a layer of sinusoidal giant cells

39
Q

What are cytotrophoblast?

A

they are the precursor to syncytiotrophoblast

40
Q

What kind of blood

A

Rodents have more branching called a labrynth. Maternal interactions are through a blood space nevertheless.

41
Q

What is different about rodent placental function compared to humans?

A

Rodents have more cell types and each cell type does a different function.
Humans have more functions being performed by the same cells

42
Q

What is the function of the junctional zone?

A

rodents have a junctional zone which produce hormones

43
Q

What is the extravillous region?

A

The point of the maternal uterus that interacts with the placenta.

44
Q

What 2 regions can be found in the placenta?

A

Villous region

Extravillous region

45
Q

How do perturbations affect males and females?

A

Males and females are often impacted in different ways by maternal factors

46
Q

What were the effects of famine on the placenta?

A

Lighter placenta

Reduced surface area

This affected boys more than girls

47
Q

What is the result of reduced placental size and surface area?

A

Glucose intolerance

Coronary heart disease

Increased stress responsiveness

Obesity

48
Q

What is the placental ratio important for?

A

If the placenta is too large it is often inefficient.

If the placenta is too small it is poorly developed and also not effective.

The ideal ratio provides optimal growth.

49
Q

What is the placental ratio?

A

Ratio between

fetus weight:placenta weight

50
Q

What is the effect of surface area on cardiovascular disease risk?

A

If the placenta has too much or too little surface area there is an increase of cardiovascular risk with age.

51
Q

What are some conditions that are correlated with a high placental ratio?

A

Hypertension

Coronary Heart Disease in both men and women

Glucose intolerance

52
Q

What are some conditions that are correlated with a low placental ratio?

A

coronary heart disease in males.

53
Q

What are some causes of problems during fetal development caused by the placenta?

A

impaired placental structure.

Dysregulated nutrient transport

Impaired endocrine functions

dysregulated placental barrier.

54
Q

Why are male babies more prone to developmental programming of disease?

A

placenta of male fetus prioritise making baby large. Female placenta doesn’t mind.

55
Q

What does HSD11B2 break down cortisol into?

A

cortisone

56
Q

What does HSD11B2 break down corticosterone into?

A

11 deoxycorticosterone

57
Q

What does HSD11B2 break down dexamethasone (DEX) into?

A

11-ketodexamethasone

58
Q

How is HSD11B2 related to programming of disease?

A

HSD11B2 can be dysregulated by multiple perturbations in maternal physiology.

59
Q

What is the effect of ethanol on the placenta in females compared to males?

A

Placenta is better protected from ethanol in females than in males.

60
Q

What does hypoxia do to HSD11B2 expression?

A

hypoxia reduces HSD11B2

61
Q

What are the adaptations that cause males to be more likely to develop disease than females?

A

Males take more risky growth than females.