physiology of pregnancy

Question 1

what tissue is the placenta derived from

Answer 1

trophoblast and decidual tissue

Question 2

at what stage of pregnancy is the placenta and foetal heart functional

Answer 2

5th weeks of pregnancy

Question 3

what provides nutrition to the embryo in the early stages of pregnancy

Answer 3

invasion of trophoblastic cells into the decidua

Question 4

what effect does HCG have on the corpus luteum in early pregnancy

Answer 4

signals it to continue secreting progesterone

progesterone stimulates decidual cells to concentrate glycogen, proteins and lipids

Question 5

how does the placenta maximise contact area with maternal circulation

Answer 5

extends hair-like projections (villi) into the uterine wall

Question 6

what sort of blood is contained in the umbilical circulation

Answer 6

mixed arterial and venous blood

oxygen-poor

Question 7

foetal, oxygen saturated blood returns to the fetus via …..

Answer 7

the umbilical vein

Question 8

maternal, oxygen-poor blood flows back into the …..

Answer 8

uterine veins

Question 9

supply of the fetus with oxygen is facilitated by which three factors

Answer 9

fetal Hb (increased ability to carry O2)
higher Hb concentration in fatal blood
Bohr effect (fetal Hb can carry more O2 in low pCO2 than in high pCO2)

Question 10

effect of HCG

Answer 10

prevent involution of corpus luteum

effect on the testes of male fetus (development of sex organs)

Question 11

effects of HCS

Answer 11

produced week 5 of pregnancy
growth hormone-like effects (protein tissue formation)
decreases insulin sensitivity in mother (more glucose for fetus)
involved in breast development

Question 12

effects of progesterone

Answer 12

development of decidual cells
decreases uterus contractility
preparation for lactation

Question 13

effects of estrogens

Answer 13

enlargement of uterus
breast development
relaxation of ligaments

Question 14

why does CO increase during pregnancy

Answer 14

due to demands of the uteroplacental circulation

Question 15

during which trimester does BP drop

Answer 15

2nd trimester

Question 16

why might a pregnant person become faint when lying supine towards the end of the pregnancy

Answer 16

the uterus compresses the vena cava

Question 17

physiological changes to lower CO2 levels

Answer 17

respiratory rate increases 
tidal and minute volume increases 
pCO2 decreases slightly 
vital capacity and pO2 don't change 
(progesterone)

Question 18

physiological changes in urinary system

Answer 18

glomerular filtration rate and renal plasma flow increases
increased reabsorption of ions and water
slight increase in urine formation

Question 19

how do postural changes affect renal functions

Answer 19

upright position = decrease
supine position = increase
lateral position during sleep = increaseee

Question 20

what is pre-eclampsia

Answer 20

pregnancy induced hypertension and proteinuria

Question 21

signs of pre-eclampsia

Answer 21

increasing BP since 20th weeks

oedema in hands and face

Question 22

what is the single most significant risk for pre-eclampsia

Answer 22

having had pre-eclampsia before

Question 23

what causes pre-eclampsia

Answer 23

insufficient blood supply to placenta

Question 24

what are signs of eclampsia

Answer 24

vascular spasms
extreme HTN
chronic seizures
coma

Question 25

treatment of eclampsia

Answer 25

vasodilator | c-section

Question 26

what is the average weight gain during pregnancy

Answer 26

24 lbs

Question 27

what are the components that make up the weight gain during pregnancy

Answer 27

``` fetus extra-embryonic fluid/tissues uterus breasts body fluid fat accumulation ```

Question 28

how many extra calories should be consumed by the mother

Answer 28

250-300 calories a day

Question 29

what are the 2 phases of pregnancy (regarding maternal-fetal metabolism)

Answer 29

1st-20th week = mother's anabolic phase | 21st-40th weeks = mother's catabolic phase

Question 30

what happens with the mother's anabolic phase

Answer 30

normal or increased sensitivity to insulin lower plasmatic glucose level lipogenesis, glycogen stores increase growth of breasts, uterus, weight gain

Question 31

what happens during catabolic phase

Answer 31

maternal insulin resistance increased transport of nutrients through placental membrane lipolysis

Question 32

special nutritional needs in pregnancy

Answer 32

``` folic acid vit D high protein diet iron supplements b vitamins ```

Question 33

effect of oestrogen:pregesterone ratio on uterus excitability

Answer 33

progesterone inhibits contractility | oestrogen increases contractility

Question 34

where is oxytocin produced

Answer 34

maternal posterior pituitary

Question 35

what is the function of oxytocin during parturition

Answer 35

increases contractions and excitability

Question 36

which fetal hormones are involved in parturition

Answer 36

oxytocin adrenal gland prostaglandin

Question 37

mechanical factors tan increase contractility

Answer 37

mechanical stretch of uterus | stretch of cervix

Question 38

what kind of feedback is involved in the onset of labour

Answer 38

positive feedback | stretch of the cervix by fetal head increases contractions

Question 39

which hormone is released in response to cervical stretch in the initiation of labour

Answer 39

oxytocin

Question 40

which hormones are released in response to oxytocin release

Answer 40

prostaglandins

Question 41

what is the first stage of labour

Answer 41

cervical dilation (8-24 hours)

Question 42

what is the second stage of labour

Answer 42

passage through birth canal (few minutes to 120 minutes)

Question 43

3rd stage of labour

Answer 43

expulsion of placenta

Question 44

what hormones are involved in producing and releasing milk

Answer 44

oestrogen: growth of ductile system progesterone: development of lobule-alveolar system prolactin: stimulate milk production

Question 45

which hormones inhibit milk production during pregnancy

Answer 45

oestrogen and progesterone

Question 46

what are the 5 steps of the milk let-down reflex

Answer 46

``` 1 - receptors in nipple stimulated 2 - impulses propagated to spinal cord 3 - stimulation of hypothalamic nuclei 4 - oxytocin released 5 - milk ejected ```