Physiology of Pregnancy and Lactation Flashcards Preview

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Flashcards in Physiology of Pregnancy and Lactation Deck (45)
1

At what stage does the embryo implant into the uterus

Blastocyst- inner cells become embryo. Outer cell burrow into uterine wall and become placenta

2

What is the stage before blastocyst

Morula

3

When does the blastocyst attach to the lining of the uterus

Day 5-8

4

What are the surface layer cells of the blastocyst called

trophoblast

5

By what day does the blastocyst become buried in the uterine lining

day 12

6

What is the placenta made from

Trophoblast and decidual tissue

7

When is the placenta and foetal heart functional

by week 5 of the pregnancy

8

How is the placental developed

Invasion of trophoblastic cells into the decidua
HCG is secreated which signals to the corpus luteum to continue to secret progesterone - this stimulate decidual cells to concentrated glycogenm proteins and lipids to help placental development

9

How does fetal, oxygenated blood return to the fetus

via the umbilical vein

10

how does maternal, now oxygen poor blood flow from the intervillous space back to the maternal circulation

via the uterine arteries

11

What is different about fetal Hb

increased ability to carry oxygen
higher Hb conc in fetal blood
Fetal Hb can carry more oxygen in low PCO2 than high pCO2

12

What is the function of HCG

prevents involution of the corpus luteum (progesterone production maintained)
effect on testes of mall fetus - helps develop sex organs

13

What is human chorionic somatomammotropin (HCS)

Growth hormone like effects - protein tissue formation
Decreases insulin sensitivity in the mother - more glucose available for the fetus
Involved in breast development and possibly lactation (?)

14

When is HCS produced

from week 5

15

what is the function of progesterone

development of decidual cels
decreases uterus contractility
preparation for lactation

16

What is the purpose of oestrogens

enlargement of uterus
breast development
relaxation of ligaments

17

what does the estriol level indicate

the vitality of the fetus

18

What conditions can result as a consequence of hormonal changes in pregnancy

Hypertension
Diabetes
Hyperthyroidism
Hyperparathyroidism

19

Why can hypertension and diabetes occur

CRH is increased -- ACTH increases -- aldosterone increases = HYPERTENSION
Increased ACTH -- increased cortisol -- insulin resistance and oedema = gestational diabetes.

20

Why can hyperthyroidism occyr

HCG can causes increase thyroxin

21

Why can hyperparathyroidism occur

increased calcium demands

22

how much does the cardiac output increase in pregnancy

30-50 percent beginning week 6 and peaking at wk 24

23

Why is the CO increased in pregnancy

demands of uteroplacental circulation
increases metabolism
renal circulation
thermoregulation

24

when does the CO decrease in pregnancy and why is this

the last 8 weeks - the uterus compresses vena cava
but increases again in labour

25

How are the heart rate and BP affected by pregnancy

Hr- increased up to 90/min
BP- drops during second trimester

26

What are the haematological changes in pregnancy

Plasma volume increases
Erythropoeiss increased by 1/4
Hv is decreased by dilutsion and this decreases blood viscosity
Iron requirements increase to 6-7mg/day in 2nd half

27

Why do lung changes occur

Progesterone increase - progesterone signals the brain to lower CO2 levels
enlarging uterus interferes with lung function
O2 consumption increases

28

How are CO2 levels lowered

increased resp rate
tidal and minute volume increases
PCO2 decreases

no change on PO2 or vital capacity

29

What changes occur in the urinary system

glomerular filtration rate and renal plasma flow increase up to 30-50 percent
increased reabsorption of ions and water
slight increase in urine formation

30

why is there more reabsorption of ions and water

because of increased aldosterone
and increased placental steroids

31

how do postural changes affect renal function

upright position - decreased
supine- increased
lateral position during sleep - very increased

32

How much weight does a mother typicaly gain

11kgs
5- fetus
6- mother

33

how many extra calories should be ingested a day in pregnancy

250-300
30g extra protein

34

When does the fetus have high metabolic demands

wks 21-40

35

What special nutritional needs are there in pregnancy

high protein diet
iron supplements 300mg
B vitamins for erythropoesis
folic acid
vit D3 and calcium supplements
vitamin K before parturition

36

What happens to the oestrogen:progesterone ratio in parturition

Oestrogen increases as it increases contractility while progesterone inhibits it

37

What other factors increase contractility

Maternal and fetal oxytocin
mechanical stretch of uterine muscle fibres
stretch of the cervix

38

what does prostaglandidn fo

control timing of labour

39

What effect does oestrogen and progesterone do in terms of lactation

Oestrogen - growth of ductile system
Progesterone- development of lobule alveolar system

Both inhibit milk production so their levels drop suddenly at birth

40

What does prolactin do

stimulates milk production
stimulates colostrum

41

describe the milk let down reflex

receptors in nipples stimulated- impulses propagates to spinal cord- stimulation of hypothalamic nuclei- oxytocin released- contraction- milk ejected

42

where is oxytocin released from

the posterior pituitary gland

43

describe the mothers nutritional status throughout pregnancy

wks 1-20 = anabolic
wks 21-40= catabolic ie fetus has high demands, mother experiences accelerated starvation

44

what happens in the anabolic phase

normal or increases insulin sensitivity
lower plasmatic glucose level
lipogeneis, glycogen stores
growth of breasts, uterus, weight gain

45

what causes insulin resistance in pregnancy

HCS
cortisol
growth hormone