Physiology of Pregnancy and Lactation

Question 1

What does the fertilised ovum do?

Answer 1

Progressively divides and differentiates into a blastocyst

Question 2

Where does the fertilised ovum move to?

Answer 2

Site of fertilisation in the upper oviduct (ampulla to the site of implantation in the uterus

Question 3

What sweeps the ovum into the oviduct?

Answer 3

Fimbrae

Question 4

What happens at day 1?

Answer 4

Fertilisation occurs in the ampulla of the fallopian tube

Question 5

What happens at days 3-5?

Answer 5

Transport of blastocyst into the uterus

Question 6

What happens at days 5-8?

Answer 6

Blastocyst attaches to lining of uterus

Question 7

What happens to the blastocyst?

Answer 7

Inner cells develop into embryo

Outer cells burrow into uterine wall and become placenta

Question 8

What does the placenta do?

Answer 8

Produce several hormones to maintain pregnancy

Question 9

What happens when the blastocyst adheres to the endometrial lining?

Answer 9

Cords of trophoblastic cells begin to penetrate the endometrium

Question 10

What happens by day 12?

Answer 10

Implantation is completed and the blastocyte is buried in the uterine lining

Question 11

What is the placenta derived from?

Answer 11

Trophoblast and decidual tissue

Question 12

What happens to trophoblastic cells (Chorion)?

Answer 12

Differentiates into multinucleated cells (Syncytiotrophoblasts) which invade decidua and break down capillaries to form cavities filled with maternal blood

Question 13

How are placental villi formed?

Answer 13

Embryo sends capillaries into the syncytiotrophoblast projections

Question 14

What does each villus contain?

Answer 14

Foetal capillaries separated by maternal blood by a thin layer of tissue

Question 15

Is there any direct contact between foetal and maternal blood?

Answer 15

No

Question 16

What is functional by week 5 of the pregnancy>

Answer 16

Placenta

Foetal heart

Question 17

What helps with embryo nutrition?

Answer 17

Invasion of trophoblastic cells into the decidua

Question 18

What does Human chorionic gonadotrophin (HCG) do?

Answer 18

Signals the corpus luteum to continue secreting progesterone - stimulating decidual cells to concentrate glycogen, proteins and lipids

Question 19

What acts as an arteriovenous shunt?

Answer 19

Circulation within the intervillous space

Question 20

What does the placenta play the role of?

Answer 20

The foetal lungs

Question 21

What 3 factors facilitate the oxygen supply to the foetus?

Answer 21

Fetal Hb (increased ability to carry O2)
Higher Hb (concentration in fetal blood 50% more than in adults)
Bohr effects (fetal Hb can carry more O2 in low pCO2 than in higher pCO2)

Question 22

Water diffusion increases until which week?

Answer 22

35th (3.5l/day)

Question 23

When is a higher concentration of glucose required?

Answer 23

3rd trimester

Question 24

Describe Human Chorionic Somatomammotrophin (HCS)

Answer 24

Produced from week 5
Growth hormone effect
Decreases insulin sensitivity in mother
Involved in breast development

Question 25

What does changes in progesterone cause?

Answer 25

Development of decidual cells Decreased uterus contractibility Preparation for lactation

Question 26

What does changes in estrogens cause?

Answer 26

Enlargement of uterus Breast development Relaxation of ligaments Estriol level - indicator of vitality of foetus

Question 27

Cardiac output increases by what until when?

Answer 27

Up by 30-50% until last 8 weeks

Question 28

How high is the heart rate to accomodate the increased CO?

Answer 28

90/min

Question 29

When does the BP drop?

Answer 29

2nd trimester

Question 30

What happens to the CO and BP if the mother is carrying twins?

Answer 30

CO increases more | BP drops more

Question 31

What happens to the plasma volume?

Answer 31

Increases proportionally with CO (50%)

Question 32

What happens to Hb?

Answer 32

Decreases by dilution (Decreases blood viscosity)

Question 33

What respiratory changes happen to lower CO2 levels?

Answer 33

Respiratory rate increases Tidal volume and minute volume increase (50%) pCO2 decreases slightly Vital capacity and pO2 don't change

Question 34

What happens to the Glomerular Filtration Rate and Renal Plasma Flow?

Answer 34

Increases up to 30-50%, peaking at 16-24 weeks

Question 35

What are features of pre-aclampsia?

Answer 35

Oedema Hypertension Proteinuria GFR and renal plasma flow decreases

Question 36

What happens in eclampsia?

Answer 36

``` Vascular spasms Severe hypertension Chronic seizures Coma Death ```

Question 37

What is the treatment of eclampsia?

Answer 37

Vasodilators | Cesarean section

Question 38

How much extra kcal/day should be consumed by the mother?

Answer 38

250-300

Question 39

How much extra protein should the mother consume?

Answer 39

30g/day

Question 40

Describe the 1st metabolic phase of pregnancy?

Answer 40

1st-20th week Mother's anabolic phase Anabolic metabolism of the mother Quite small nutritional demands of the conceptus

Question 41

Describe the 2nd metabolic phase of pregnancy?

Answer 41

21-40th week (esp. last trimester) high metabolic demands of fetus Accelerated starvation of mother

Question 42

What happens in the mothers anabolic phase?

Answer 42

Normal or increased sensitivity to insulin Lower plasmatic glucose level Lipogenesis, glycogen stores increase Growth of breasts, uterus, weight gain

Question 43

What happens in the catabolic phase?

Answer 43

Maternal insulin resistance Increased transport of nutrients through placental membrane lipolysis

Question 44

What causes insulin resistance?

Answer 44

HCS Cortisol Growth hormone

Question 45

What is the purpose of taking folic acid (folate) during pregnancy?

Answer 45

Reduces risk of neural tube defects

Question 46

What is the purpose of taking vitamin K and when should it be taken?

Answer 46

Prevention of intercranial bleeding during labour | Before parturition

Question 47

What is erythropoesis?

Answer 47

making red blood cells

Question 48

What does cervical stretching cause?

Answer 48

Oxytocin release

Question 49

What are the 3 stages of labour?

Answer 49

1st: Cervical dilation (8-24 hrs) 2nd: Passage through birth canal (few to 30 mins) 3rd: Expulsion of placenta

Question 50

What does estrogen do to the breasts?

Answer 50

Growth of ductile system

Question 51

What does prgesterone help develop?

Answer 51

Lobule-alveolar system

Question 52

What do estrogen and progesterone inhibit?

Answer 52

Milk production

Question 53

What does prolactin stimulate?

Answer 53

Milk production