Physiology - Pregnancy and Lactation Flashcards

1
Q

what does the fertilised ovum divide and become?

A

a blastocyst

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2
Q

what occurs in the first 3-5 days following fertilisation?

A

transport of the blastocyst into the uterus

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3
Q

what happens 5-8 days post fertilisation?

A

the blastocyst attaches to the lining of the uterus

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4
Q

what do the inner cells of the blastocyst become?

A

the embryo

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5
Q

what do the outer cells of the blastocyst become?

A

the placenta

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6
Q

what happens when the blastocyst adheres to the endometrium?

A

cords of trophoblastic cells begin to penetrate the endometrium

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7
Q

when is implantation of the blastocyst completed?

A

by day 12

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8
Q

what is the placenta derived from?

A

trophoblasts

decidual tissue

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9
Q

what is another name for the trophoblast cells?

A

chorion

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10
Q

what do the trophoblast cells differentiate into?

A

multinucleate cells called synctiotrophoblasts

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11
Q

what do the syncytiotrophoblast cells do?

A

invade the decider and break down capillaries, forming cavities filled with maternal blood

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12
Q

what forms the placental villi?

A

capillaries from the developing embryo entering the syncytiotrophoblast projections in the decider

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13
Q

what do placental villi contain?

A

foetal capillaries separated from maternal blood by a thin layer of tissue

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14
Q

when are the placenta and foetal heart functional?

A

by the fifth week of pregnancy

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15
Q

what provides early nutrition to the embryo?

A

trophoblastic cells that have invaded into the decidua

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16
Q

what takes over providing nutrition to the embryo later in the pregnancy?

A

the placenta

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17
Q

what effect does HCG have on the corpus luteum?

A

signals it to keep secreting progesterone

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18
Q

what effect does progesterone have on the decidual cells?

A

stimulates them to concentrate glycogen, proteins and lipids

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19
Q

what is the outcome of the placental villi extending into the uterine wall?

A

increases contact area between the uterus and placenta allowing gate exchange of nutrients and waste

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20
Q

what plays the role of the foetal lungs?

A

the placenta - allows supply of oxygen and removal of CO2 from the foetus

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21
Q

which has higher oxygen concentration - maternal or foetal blood?

A

maternal

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22
Q

in which direction does oxygen diffusion in the placenta occur?

A

from the maternal circulation to the foetal circulation

PO2 maternal > PO2 foetal

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23
Q

in which direction does CO2 diffusion occur in the placenta?

A

from the foetal circulation to the maternal circulation

maternal CO2 < foetal CO2

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24
Q

where does foetal blood go after getting oxygen from the placenta?

A

returns to the foetus via the umbilical vein

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25
Q

where does maternal blood go after giving oxygen to the placenta?

A

back into the uterine veins

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26
Q

what three factors facilitate the supply of the foetus with oxygen?

A

foetal Hb
higher Hb concentration in foetal blood
Bohr effect

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27
Q

how is foetal Hb different from adult Hb?

A

has an increased ability to carry oxygen

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28
Q

which has a higher Hb concentration - foetal blood or maternal blood?

A

foetal

this enables greater oxygen transport

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29
Q

how does the Bohr effect facilitate oxygen transport in the foetus?

A

foetal Hb can carry more oxygen in low pCO2 than in high pCO2

this is good because foetal CO2 < maternal CO2

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30
Q

in which direction does water travel across the placenta and via what mechanism?

A

from mother to foetus

via osmosis

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31
Q

what amount of water is exchanged across the placenta in pregnancy?

A

increases up to the 35th week where it is around 3.5L per day

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32
Q

how do electrolytes cross the placenta?

A

follow the water that moves via osmosis

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33
Q

which electrolytes go ONLY from mother to child across the placenta?

A

iron and calcium

need to ensure mothers have adequate levels of these substances

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34
Q

how does glucose pass across the placenta?

A

via simplified transport

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35
Q

what is the foetuses main source of energy?

A

glucose

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36
Q

at which point in pregnancy is most glucose required?

A

in the third trimester

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37
Q

how do fatty acids move across the placenta?

A

via free diffusion

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38
Q

name four hormones that change throughout pregnancy

A

HCG
HCS/HPL
oestrogen
progesterone

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39
Q

what does HCG stand for?

A

human chorionic gonadotrophin

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40
Q

what does HCG do?

A

prevents involution of the corpus luteum

this stimulates progesterone and oestrogen production

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41
Q

what effect does HCG have on male foetuses?

A

aids in the development of the sex organs

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42
Q

describe the levels of HCG throughout pregnancy

A

highest in early pregnancy

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43
Q

what is another name for human placental lactogen (HPL)?

A

human chorionic somatomammotropin

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44
Q

when is HPL produced?

A

from around week 5 in pregnancy

continues to rise throughout pregnancy

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45
Q

what are the three main effects of HPL?

A

growth hormone like effects - protein tissue formation

decreases maternal insulin sensitivity

involved in breast development

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46
Q

what effect does decreasing insulin sensitivity in the mother have on the foetus?

A

allows more glucose to be provided for the foetus

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47
Q

what three effects does progesterone have throughout pregnancy?

A

development of decidual cells

decreases uterine contractility

prepares the body for lactation

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48
Q

describe levels of progesterone and oestrogen throughout pregnancy

A

rise throughout pregnancy

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49
Q

what three effects do oestrogen have during pregnancy?

A

enlargement of the uterus

breast development

relaxation of the pelvic ligaments

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50
Q

what happens to serum HCG levels in early singleton pregnancy?

A

double every 48 hours

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51
Q

what are HCG levels like in an ectopic pregnancy?

A

static or slow rising

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52
Q

what are HCG levels like in a failing pregnancy?

A

reducing

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53
Q

what side effects can HCG cause?

A

nausea and vomiting

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54
Q

when can HCG levels be higher than normal?

A

multiple pregnancies

molar pregnancy

55
Q

when do HCG levels start to fall?

A

from 12-14 weeks

56
Q

what effect does placental CRH have on the mother?

A

increased ACTH resulting in increased aldosterone and cortisol

57
Q

what effect can increased aldosterone have in a pregnant mother?

A

hypertension

58
Q

what effect can increased cortisol have in a pregnant mother?

A

oedema

insulin resistance = gestational diabetes

59
Q

what possible effect can HCG have on a pregnant mother?

A

hyperthyroidism

60
Q

what possible effect can increased calcium demands in pregnancy have on the mother?

A

hyperparathyroidism

61
Q

what happens to CO during pregnancy?

A

rises to 30-50% above normal

62
Q

what causes the increase in CO during pregnancy?

A

the demands of the uteroplacental circulation

63
Q

describe the CO throughout pregnancy?

A

begins to rise at 6 weeks
peaks around 24 weeks
decreases in the last 8 weeks
increases again during labour

64
Q

what change in heart rate occurs during pregnancy?

A

increases up to 90/min to increase CO

65
Q

what change in blood pressure occurs during pregnancy?

A

does during the second trimester

66
Q

what causes the drop in BP in the second trimester?

A

the uteroplacental circulation expands and peripheral resistance decreases

67
Q

how are the cardiovascular changes in pregnancy different when it is a multiple pregnancy?

A

CO increases more

BP drops more

68
Q

is average pregnancy BP usually higher or lower than pre-pregnancy BP?

A

lower - usually by 15mmHg

69
Q

what are BP levels like by the time the baby reaches term?

A

back to pre-pregnancy levels

70
Q

what three haematological changes happen in the mother during pregnancy?

A

plasma volume increases

erythropoiesis increases

Hb is decreased by dilution

71
Q

what happens to iron requirements during pregnancy and what can be done for this?

A

they increase significantly

iron supplements are often needed to prevent anaemia

72
Q

what is the definition of anaemia in the first trimester?

A

Hb <110g/L

73
Q

what is the definition of anaemia in the second and third trimesters?

A

<105g/L

74
Q

what is the normal definition of anaemia?

A

Hb 120-160g/L

75
Q

what causes respiratory changes during pregnancy in the mother?

A

progesterone increases

enlarging uterus interferes with lung function

76
Q

what happens to the GFR and renal plasma flow in a pregnant mother?

A

increase

peaks at 16-24 weeks

77
Q

what drives the increased re-absorption of ions and water in pregnancy?

A

placental steroids

aldosterone

78
Q

what effect does an upright position have on renal function in pregnancy?

A

decreases

79
Q

what effect does an supine position have on renal function in pregnancy?

A

increases

80
Q

what effect does a lateral position during sleep have on renal function in pregnancy?

A

increases LOTS

81
Q

what is the reference range for ALT in a pregnant individual?

A

<30

82
Q

what is the reference range for urea in a pregnant individual?

A

<3.5

83
Q

what is the reference range for creatinine in a pregnant individual?

A

<50

84
Q

what is the reference range for albumin in a pregnant individual?

A

20-40

85
Q

what change occurs to maternal coagulation during pregnancy?

A

hyper coagulable state

86
Q

what effects does the maternal hypercoagulable state have?

A

reduces risk of haemorrhage

increases risk of VTE

87
Q

what happens to factor II levels in pregnancy?

A

no change

88
Q

what happens to factor VII, IX, X and XII levels in pregnancy?

A

increase

89
Q

what happens to fibrinogen levels in pregnancy?

A

increases

90
Q

what happens to factor XI levels in pregnancy?

A

reduce

91
Q

what happens to protein S levels in pregnancy?

A

reduce

92
Q

what happens to protein C levels in pregnancy?

A

no change

93
Q

what happens to antithrombin levels in pregnancy?

A

no change

94
Q

what happens to plasminogen levels in pregnancy?

A

increase

95
Q

what happens to D-dimer levels in pregnancy?

A

increase

96
Q

what happens to vWF levels in pregnancy?

A

increase

97
Q

what weight change is normal during pregnancy?

A

average weight gain of around 11kg

can sometimes be up to 30kg

98
Q

how many extra calories per day should be ingested by a pregnant mother?

A

200

99
Q

what should the protein intake of a pregnant mother be?

A

extra intake of 30g/day

100
Q

what are the two phases of pregnancy as defined by the mothers metabolism?

A

mothers anabolic phase in 1st - 20th week

21-40 week - catabolic phase

101
Q

describe the metabolic needs of the mother and foetus during weeks 1-20

A

anabolic metabolism of the mother

quite small nutritional demands of the foetus

102
Q

describe the metabolic needs of the mother and foetus during weeks 21-40

A

high metabolic demands of the foetus

results in accelerated starvation of the mother

103
Q

what causes maternal insulin resistance?

A

HPL
cortisol
growth hormone

104
Q

what effect does folic acid have in pregnancy?

A

reduces the risk of neural tube defects

105
Q

how much folic acid should be taken throughout pregnancy?

A

400mcg per day in the first 12 weeks

ideally also for three months prior to conception

106
Q

what dose of vitamin D supplements should be taken during pregnancy?

A

10mcgs a day

20mcgs if BMI > 30

107
Q

what happens to the uterus towards the end of pregnancy?

A

it becomes progressively more excitable

108
Q

what effect do progesterone and oestrogen have on uterine contractility?

A
progesterone = inhibits 
oestrogen = promotes
109
Q

what happens to progesterone levels towards term and when labour starts?

A

levels fall

110
Q

what is parturition?

A

the birth of the baby

111
Q

what are prostaglandins produced by during parturition?

A

placenta
myometrium
decidua
membranes

112
Q

what do prostaglandins do during parturition?

A

help to ripen the cervix

play a role in the onset of labour

113
Q

what produces oxytocin?

A

the maternal posterior pituitary gland

114
Q

what does oxytocin do during parturition?

A

increases contractions and excitability

115
Q

what effect does increasing foetal size have on parturition?

A

stretches uterine muscles, increasing contractility

116
Q

what substances are given to induce labour and how do they work?

A

prostaglandins - ripen the cervix

oxytocin when membranes have ruptured - increase contractions of the uterus

117
Q

when do Braxton Hicks contractions increase?

A

towards the end of pregnancy

118
Q

what are Braxton Hicks contractions?

A

sometimes called practice contractions

mild, irregular, don’t require pain relief

119
Q

when does cervical ripening occur?

A

just before the onset of labour

120
Q

what is cervical ripening?

A

the softening of the cervix ti allow duration

121
Q

what causes cervical ripening?

A

oestrogen
relax
prostaglandins

122
Q

what hormone is released in response to cervical stretching in labour?

A

further oxytocin release

123
Q

what causes intense abdominal muscle contractions in labour?

A

strong uterine contractions + pain cause neurogenic reflexes from the spinal cord, that have an impact on the abdominal muscles

124
Q

what is the first stage of labour?

A

cervical dilation

125
Q

how long does the first stage of labour take?

A

8-24 hours

126
Q

what is the second stage of labour?

A

passage of the foetus through the birth canal

127
Q

how long does the second stage of labour take?

A

from a few minutes to two hours

128
Q

what is the third stage of labour?

A

expulsion of the placenta

129
Q

what effect does oestrogen have on lactation?

A

stimulates growth of the ductile system

130
Q

what effect does progesterone have on lactation?

A

development of the lobule alveolar system

131
Q

overall, what effect do oestrogen and progesterone have on milk production?

A

INHIBITION

levels drop at birth

132
Q

what hormone stimulates milk production in lactation?

A

prolactin

133
Q

what hormone triggers the “milk let down” reflex?

A

oxytocin