Lecture 13 - Placenta III

Question 1

Human chorionic Gonadotrophin (hCG)?

Answer 1

two chain hormone, shares alpha chain with TSH, LH and FSH, all hormones have unique beta chain, produced by pre-implantation zygot and placenta, detectable in mothers blood days after implantation

Question 2

hCG concentration progression?

Answer 2

major rise following LMP, peaks around ned of 1st trimester where it flattens and then declines slightly

Question 3

hCG functions?

Answer 3

stimulate the production of progesterone and oestrogen by ovary during first 6-8wk pregnancy, doubles size of corpus luteum - essentially preventing uterus’s normal cycle and causing CL to continually secrete p and oe to maintain endometrium into duodenal form

Question 4

hCG and LH?

Answer 4

share same receptor, similar signalling pathway

Question 5

Proof of importance of hCG in pregnancy?

Answer 5

vaccine of beta-hCG antibodies induces infertility

Question 6

hCG and male fetuses?

Answer 6

LH-like activity stimulating testosterone synthesis by Leydig cells of fetal testis

Question 7

Progesterone from placenta?

Answer 7

produces by syncytiotrophoblasts using LDL-cholesterol (no ovary dependence)

Question 8

Functions of progesterone?

Answer 8

bind to receptors on glands and stromal cells in endometrium/decidua, maintain uterine inactivity (w oestrogen) for pregnancy environment

Question 9

Oestrogen from placents?

Answer 9

cannot produce from scratch, modifies testosterone and other androgens, fetus produce these androgens but cannot convert, anencephalic pregnancies have low oestrogen

Question 10

Primary maternal adaptations?

Answer 10

CVS, haemotological, immunity, genitals

Question 11

Preeclampsia?

Answer 11

dangerously elevated maternal blood pressure and protein in urine, exaggerated inflammatory response preventing normal vascular adaptation to pregnancy

Question 12

CVS adaptation?

Answer 12

increased stroke volume and pulse rate, decreased peripheral resistance (abnormally high in preeclampsia) - changes most important for first 9 weeks gestation

Question 13

Oestrogen and CV changes?

Answer 13

reduce vascular resistance (mainly reproductive), alter type I:type II ratio of collagen in vessel wall - spiked levels not reached until 9wk where fetal adrenals form

Question 14

Angiotensin II?

Answer 14

levels increase in pregnancy, but effects appear blunted (likely due to receptor changes)

Question 15

haemotological changes?

Answer 15

increase in blood volume, plasma faster than cells therefore reducing haematocrit

Question 16

Blood loss during birth?

Answer 16

half litre (full in c section and twins), but hypervolaemia means loss leads to restoration of haemotocrit

Question 17

Infections of increase severity in pregnancy?

Answer 17

listeriosis, leprosy

Question 18

Neutrophils?

Answer 18

increase in luteal phase and remainduring pregnancy, peak @ 30 weeks then rise again @ labour

Question 19

Lymphocytes?

Answer 19

th2 increase that support antibody imunity rather than th1 driven cell immunity

Question 20

Presence of T cells in decidua?

Answer 20

not high, higher in repeated miscarraige, potentially attacks placenta

Question 21

Abdominal wall and skin?

Answer 21

increased blood flow to hands and feet, pigmentation changes of skin (nipples), likely linked to melanocyte stimulating hormone