Reproduction 5: Pregnancy Flashcards Preview

FHB Block 4 > Reproduction 5: Pregnancy > Flashcards

Flashcards in Reproduction 5: Pregnancy Deck (64):
1

What is the first hormone secreted by the syncytiorophoblasts?

hCG

2

Whatdoes hCG bind to, and what does it do?

bind to LH receptors on corpus luteum and keeps it viable (rescues)

3

What do pregnancy tests detect?

hCG

4

What other cells does hCG act on?

fetal leydig cells and adrenal cortex

5

What are the feedback actions of hCG?

negative feedback on maternal HPG axis

6

What is hPL?

human placental lactogen

7

What is hPL also called?

hCS- human chorionic somatomammotropin

8

what other two hormones is hPL like?

GH and prolactin

9

How is hPL like GH?

counter-regulatory to insulin (anabolic in the fetus, lipolytic in mom)

mobilizes glucose for fetal use

stimulates fetal IGF-1

10

How is hPL like prolactin?

stimulates mammary gland development

11

What is the insulin state during pregnancy?

pregnancy is an insulin-resistant state

12

What is the result of being in an insulin resistant state?

decreased glucose use by mom allows fetal use

lipolysis and proteolysis provides fatty acids for mom and AA for fetus

13

What is gestational diabetes caused by?

anti-insulin effects of hPL, progesterone, prolactin, and cortisol

14

What are the functions of the placenta?

supportive: provides nutrients for fetal growth

immune: prevents rejection of fetus by mother

endocrine: synthesizes hormones

15

What organs does the placenta perform the functions of?

gut: supplies nutrients

lung: gas exchange

kidney: regulates fluid volume and waste disposal

endocrine

16

What can't the placenta make on its own?

cholesterol, must get it from mom - can then convert to progesterone

17

Why is the placenta considered an incomplete endocrine organ?

can't complete steroid biosynthesis - gets stuck at progesterone

18

What is unique in steroid biosynthesis in the syncytiotrophoblast?

StAR independent

19

What are the sources of cortisol to the syncytiotrophoblasts?

mother and fetal adrenal cortex

20

What is highly upregulated in the syncytiotrophoblasts, and why

11beta-HSD2, converts cortisol to cortisone, protecting the fetus from too much cortisol

21

What is relaxin?

inhibits myometrial contractions early in pregnancy

relaxes pelvic bones, ligaments, and softens cervix

involved in reversible hypertrophy of heart?

22

What produces relaxin?

corpus luteum in response to hCG and by the placenta

23

What is prolactin?

stimulates lactogenic apparatus during pregnancy

24

What is prolactin from?

not from placenta, but from maternal pituitary

25

What i prolactin essential for?

mammotrophic effects of estrogen and progesterone

26

What is significant lactation inhibited by?

high levels of estrogen and progesterone

27

What are the cardiovascular changes during pregnancy?

increased stroke volume and heart rate resulting in increased CO

catecholamines mediate chronotropic and ionotropic increases

mild cardiomegaly

28

What is the change in the MAP during pregnancy?

decreases - TPR decreases more than CO increases

29

What is the change in pulmonary pressures?

stays the same - decrease in volume offset by decrease in resistance

30

What is the change in venous pressure during pregnancy?

increases

31

What are the changes in regional blood flow during pregnancy?

uterus receives up to 30% of CO

skin blood flow increases to maintain body temp

kidney blood flow increases and GFR increases

32

What are the changes in blood during pregnancy?

increase in blood volume - up to 50% during second trimester - mediated by progesterone

plasma and RBC increase with a net decrease in Hct

33

What are the respiratory changes during pregnancy?

40% reduction in expiratory reserve due to elevation of diaphragm

increase in tidal volume with no increase in frequency

increased tidal volume results in increased alveolar ventilation - functional alkalosis

34

What are the GI changes during pregnancy?

additional 30g/day of protein required

decreased mobility which increases nutrient absorption but can result in constipation

decreased LES tone resulting in reflux

35

What are the endocrine changes during pregnancy?

HPG axis suppressed due to high concentrations of placental sex steroids

growth of pituitary lactotrophs and an increase in PRL secretion (GnRH suppression)

Ant. Pituitary increases in size by 30%

36

What are the metabolic changes during pregnancy?

first half of pregnancy mother is in anabolic state, second half in state of accelerated starvation

anabolic state: normal or increased sensitivity to insulin, increased fat deposition, glycogen stores, breast growth, nutrient stockpiling

accelerated starvation: mediated by hPL, increased plasma glucose and FA levels

37

What is accelerated starvation?

catabolic state characterized by insulin resistance

38

What is the first stage of labor?

activation of the uterus

39

What does activation of the uterus entail?

release from inhibitory actions of progesterone

Ferguson reflex

fetal HPA axis activated - CRH levels peak

40

What is the ferguson reflex?

stretch of the cervix from the fetus stimulates release of oxytocin

41

What are the hormones involved in the initiation and maintenance of labor and uterine evacuation?

progesterone, E2, relaxin, cortisol, oxytocin, CRH, prostaglandins, catecholamines

42

What is the most important hormone relationship in the initiation and maintenance of labor?

decrease in progesterone and an increase in estrogen

43

Where is oxytocin released from?

posterior pituitary

44

What does oxytocin binding to its receptor result in?

PLC cascade results in increased IP3, and an increase in Ca which activates calmodulin

increases uterine smooth muscle contractions

45

How does E2 influence the response to OT?

E2 increases the number of receptors to OT during pregnancy, increasing the potency of OT

uterus insensitive to OT until 29 wks, then gradually increases 200 fold in early labor

46

What is used to induce labor?

Pitocin - synthetic OT

47

What is OT important for in lactation?

not important in formation of milk, but rather for the release/ejection of milk

48

is maternal OT considered the signal that initiates labor?

No! levels do not increase prior to labor, but rather is released in bursts once labor begins, with increased frequency as labor continues

49

What is the signal that initiates labor?

Decrease in progesterone/E2 ratio leads to increased prostaglandins which results in increased myometrium Ca leading to more forceful contractions

50

What does OT stimulate release of?

prostaglandins (also stimulates contractions)

51

What stimulates lactation?

initiated after delivery by decreased progesterone and E2

52

What sustains milk secretion?

repeated transient hyperprolactinemia

53

What does suckling do?

stimulates prolactin release

54

What does prolactin do?

stimulates maternal behavior during pregnancy and after parturition

suppresses reproductive function (inhibits GnRH)

55

What is the fundamental secretory unit of the breast-alveolus?

contractile myoepithelial cells, adipose cells

56

What is the colostrum?

first milk produced, contains very little fat

57

What is essential for continued milk production?

prolactin, cortisol, insulin

58

What is oxytocin released in response to?

neural input to NTS (mother response to infant crying) via circulation to the breast

59

What does it mean that prolactin is a lactogenic hormone?

mammogenic effects: breast development

galactogenic effects: milk production

60

How does the pill work?

Acts on CNS and urogenital tract to inhibit reproductive function

Pituitary and Hypothalamus – prevents LH surge and ovulation

Basal gonadotropin levels are decreased

Ovary - follicular growth is inhibited

Fallopian tube motility is decreased (in vitro observation)

Glandular atrophy in uterine endometrium – why it is good for controlling heavy menstruation

Inhibits implantation of blastocyst

Causes thick cervical mucus – inhibits sperm motility and migration

61

What does the progestational drug in the pill do?

prevents LH secretion (including LH surge)

62

What does the estrogenic drug in the pill do?

inhibits FSH release

63

What are some non-contraceptive benefits to the pill?

Treatment of excessive menstrual bleeding

Protection for pelvic inflammatory disease

Dysmenorrhea

Hormone replacement therapy in postmenopausal women

64

What are some risks and side effects of the pill?

Contraindicated in heavy smokers over 35 and those with a history of estrogen-dependent breast carcinomas

Hypertension, myocardial infarction, stroke

Blood clots

Depression

Decreased libido