Physiology- Pregnancy and Lactation Flashcards Preview

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Flashcards in Physiology- Pregnancy and Lactation Deck (78)
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1

Describe the process from fertilisation to implantation

Fertilisation
Zygote
Morula
Blastocyst
Implantation

2

How many days after fertilisation does the blastocyst transport into the uterus?

3-5 days

3

How many days after fertilisation does the blastocyst attach to the lining of the uterus?

5-8 days

4

What happens to the inner cells of the blastocyst?

Develop into the embryo

5

What happens to the outer cells of the blastocyst?

Burrow into uterine wall and become placenta

6

What happens when the blastocysts adheres to the endometrial lining?

Cords of trophoblastic cells begin to penetrate the endometrium

7

What is the trophoblast?

Surface layer of cells of the blastocyst

8

What do the cords of trophoblastic cells do after endometrium penetration?

Tunnel deeper, carving out a hole for the blastocyst. Boundaries between cells in the advancing trophoblastic tissue disintegrate

9

Where is the blastocyst when implantation is finished?

Completely buried in endometrium

10

By what day will the blastocyst be buried in the uterine lining?

Day 12

11

What is the placenta derived from?

Trophoblast and decidual tissue

12

Describe how cavities filled with maternal blood are formed from trophoblast cells

Cells (chorion) differentiate into multinucleate cells (syncytiotrophoblasts) which invade decidua and break down capillaries to form cavities

13

Describe what happens to the broken down capillaries in the forming of cavities

Developing embryo sends capillaries into the syncytiotrophoblast projections to form placental villi

14

Describe a placental villus

Each contains foetal capillaries separated from maternal blood by a thin layer of tissue- no direct contact between foetal and maternal blood

15

What type of exchange exists between mother and foetus?

2 way exchange of resp gases, nutrients, metabolites etc-largely down diffusion gradient

16

When are the placenta and foetal heart functional by?

5th week of pregnancy

17

What provides early nutrition to the embryo?

Invasion of trophoblastic cells into decidua

18

What does HCG signal the corpus luteum to continue secreting?

Progesterone- stimulates decidual cells to concentrate glycogen, proteins and lipids

19

Where do placental villi extend into?

The uterine wall

20

What is the purpose of placental villi?

Increases contact area between uterus and placenta & more nutrients and waste materials can be exchanged

21

What does circulation within the intervillous space of the placenta act as?

An arteriovenous shunt

22

What plays the role of the foetal lungs?

Placenta

23

What is contained within umbilical blood?

Mix of arterial and venous blood

24

What does the exchange of CO2 follow from mother to foetus?

Reversed gradient to oxygen
Partial pressure elevated in foetal blood

25

What does foetal, oxygen saturated blood return to the foetus via?

The umbilical vein

26

What does maternal, oxygen poor blood return to the mother via?

Uterine veins

27

What 3 factors facilitate the supply of oxygen to the foetus?

Foetal Hb: increased ability to carry O2
Higher Hb concentration in foetal blood (50% more than adults)
Bohr effect: Foetal Hb can carry more oxygen in low pCO2 than higher pCO2

28

What transport mechanisms do the placental exchange processes occur via?

Passive transport (without energy consumption)
Simple diffusion
Osmosis
Simplified transport
Active transport

29

Describe water diffusion into placenta

Osmotic gradient
Exchange increases during pregnancy up to 35th week (3.5l/day)

30

Describe electrolyte transport into placenta

Follow water
Iron and Ca2+ only go from mother to child