Repro 8 Flashcards Preview

ESA 4 - 2017 - Incomplete/Some errors > Repro 8 > Flashcards

Flashcards in Repro 8 Deck (43)
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1
Q

The human placenta is haemomonochorial, what does this mean?

A

There is only one layer of trophoblast separating maternal blood from foetal capillary wall

2
Q

What is placenta praevia?

A

Implantation in lower uterine segment, requires C-section and can cause haemorrhage

3
Q

How is the endometrium prepared for implantation?

A

“Pre-decidual” cells in preparation for decidualisation

Elaboration of spiral arterial supply

4
Q

What is decidualisation?

A

A reaction balancing the force of invasion of the trophoblast. can occur in ectopic pregnancy

5
Q

How are the spiral arteries remodelled?

A

Low resistance vascular bed created

Maintains high flow

6
Q

Describe the development of the foetal membranes?

A

Initially chorion has villi all round (wk5)
Villi are lost leaving them only in decidua basalis (wk12)
Amnion joins chorion to become one membrane

7
Q

What is twinning?

A

The degree to which membranes are shared in monozygotic twins

8
Q

What are the three degrees of twinning?

A

Share both amnion and chorion
Share neither
Share just chorion

9
Q

Describe the placenta in 1st trimester

A

Established
Barrier still thick
Complete cytotrophoblast layer beneath syncytiotrophoblast

10
Q

Describe the placenta at term

A

SA for exchange increased lots
Placental barrier thin
Cytotrophoblast layer lost

11
Q

How many umbilical arteries are there? What is their function?

A

2 - carry deoxygenated blood foetus -> placenta

12
Q

How many umbilical veins are there? What is their function?

A

1 - carries oxygenated blood placenta -> foetus

13
Q

What are the three main functions of the placenta?

A

Metabolism
Endocrine
Transport

14
Q

What are the metabolic functions of the placenta?

A

Synthesis of glycogen, cholesterol and FAs

15
Q

What are the endocrine functions of the placenta?

A

Production of; hCG, hC Somatomammotrophin, hC thyrotrophin, hC corticotrophin, progesterone and oestrogen

16
Q

What are the functions of human chorioni gonadotrophin?

A

Supports secretion by corpus luteum
Pregnancy specific and excreted in maternal urine so can be test
Reduces risk of trophoblast disease

17
Q

At what point does the corpus luteum stop producing progesterone and oestrogen? Why?

A

11th week - placenta takes over

18
Q

How do placental hormones influence maternal metabolism?

A

Progesterone increases appetite

hCS/hPL increase glucose availability to foetus

19
Q

How is gas exchange limited in the foetus?

A

Flow-limited i.e. foetal stores are small

20
Q

How is active transport carried out between foetus and mother?

A

“Transporters” expressed by syncytiotrophoblast; AAs, iron, vitamins

21
Q

How is passive immunity established initially in the foetus?

A

IgG only - conc. higher in foetal plasma than maternal circulation

22
Q

What is a teratogen?

A

An agent or factor causing malformation of an embryo

23
Q

List some common teratogens

A

Thalidomide
Alcohol
Cigarette smoke

24
Q

Why are teratogens significant to the placenta?

A

As it is not a “true” barrier they can access foetus through it

25
Q

List some infectious agents relevant to the placenta

A

Varicella zoster
Cytomegalovirus
Treponema pallidum
Rubella

26
Q

How does the maternal cardiovasuclar system change during pregnancy?

A

Blood volume increase
CO, SV and HR increase
BP drops T1-2, normal in T3

27
Q

What caues low BP in pregnancy?

A

Progesterone reduces sytemic vascular resistance

28
Q

What casues the return to normal BP in T3 of pregnancy?

A

Aortocaval compression by gravid uterus

29
Q

what is the role of the endothelium in pregnancy?

A

Controls vascular permeability

Contributes to control of vascular tone

30
Q

What is pre-eclampsia?

A

A defect in placentation; vasoconstriction causing high BP with contracted plasma

31
Q

Which aspects of the maternal urinary system increase during pregnancy?

A

Renal plasma flow
GFR
Creatinine clearance
Protein excretion

32
Q

Which aspects of the maternal urinary system decrease in pregnancy?

A

Urea
Uric acid
Bicarbonate
Creatinine

33
Q

What are the consequences of changes to the maternal urinary system in pregnancy?

A

Progesterone causes hydroureter

Possible pyelonephritis

34
Q

What changes occur in the respiratory system of pregnant women?

A
Diaphragm displaced 
Diameters of thorax increase
Increased ventilation
Increased tidal volume
Decreased functional residual capacity
35
Q

What problems can occur in the respiratory system of pregnant women?

A

Physiological hyperventialtion; increased CO2 production, progesterone increases respiratory drive

36
Q

How does pregnancy alter carbohydrate metabolism?

A

Increased maternal peripheral insulin resistance due to action of hPL, switch to alternative fuels

37
Q

What is gestational diabetes?

A

Carbohydrate intolerance first recognised in pregnancy but not persisting after delivery

38
Q

List some risk factors of gestational diabetes

A

Prediabetes
Hypertension
FH of it or type II DM

39
Q

How is lipid metabolism altered in pregnancy?

A

Increase in lipolysis from T2

Increased plasma FFAs on fasting

40
Q

How is the thyroid gland alterd in pregnancy?

A

Thyroid binding globulin production increased
T3&4 increased
hCG directly affects TSH (can lower it)

41
Q

How does pregnancy alter the haematological state of the mother?

A

Pro-thrombotic state
++ fibrin at implantation site
More fibrinogen & clotting factors
Reduced fibrinolysis

42
Q

Why can warfarin not be used in thromboembolic disease during pregnancy?

A

Crosses the placenta and is teratogenic

43
Q

How can physiological anaemia occur in pregnancy?

A

Blood volume increase not met with sufficient red cell mass increase