Control of pregnancy and birth

Question 1

what does hCG stand for?

Answer 1

Human chorionic Gonadotrophin

Question 2

what is hCG produced by?

Answer 2

trophoblast

Question 3

what is the trophoblast?

Answer 3

cells that form the otter layer of a blastocyst (inner cell mass)

Question 4

what does hCG do?

Answer 4

supports the CL to keep producing oestrogen and progesterone, preventing menstruation

Question 5

when does hCG production peak?

Answer 5

10 weeks

Question 6

what happens at the 10 week point to hCG production?

Answer 6

peaks and then the placenta takes over

Question 7

Where are oestrogen and progesterone produced from during pregnancy?

Answer 7

-1st 3 months from the CL (driven by hCG) and then after from the placenta-linked to foetus

Question 8

What does oestrogen do during pregnancy?

Answer 8

stimulates uterine growth, prepares the uterus for labour and promotes breast duct development

Question 9

what controls oestrogen during pregnancy?

Answer 9

placental CRH (corticotropin=ACTH… adrenocorticotrophic hormone)

Question 10

What does progesterone do during pregnancy?

Answer 10

relaxes the uterus, promotes a cervical plug and stimulates milk gland development in breast

Question 11

what is progesterone synthesised from and where?

Answer 11

Synthesised in the placenta from cholesterol

Question 12

4 main things oestrogen does during pregnancy.

Answer 12

-promotes connections (gap junctions) between the myometrial cells
-makes the myometrium more sensitive to ooxytocin
increases prostaglandin production
-promotes mamary duct development

Question 13

Oestrogen, by making the myometrium more sensitive to oxytocin and promoting gap junction formation in myometrium what does this do?

Answer 13

increases the uterine contractility

Question 14

what does an increase in prostaglandin production due to oestrogen do?

Answer 14

softens the cervix

Question 15

why does HPL stand for?

Answer 15

Human placental location (aka human chorionic somatotropin)

Question 16

what does HPL do?

Answer 16

Anti-insulin action in mother boosts available nutritional substrate…
its a placental derived peptide hormone, supports foetal well being

Question 17

describe what the uterine is like in each trimester during pregnancy.

Answer 17

1+2 trimester= quiet uterus (progesterone effect)

3 trimester= generally increasing uterine excitability, mild contractions

Question 18

what is relaxin, what produces it and what does it do?

Answer 18

Hormone produced by the CL and the placenta. Causes the softening of the cervix and pelvis ligaments

Question 19

what does the increase in uterine contractions cause?

Answer 19

• foetus to press on the cervix
• dilation of cervix
• +ve feedback involving oxytocin
• foetus forced out through birth control

Question 20

what does oxytocin do?

Answer 20

-promotes uterine contractions in the final stages via positive feedback through various pathways

Question 21

what is the positive feedback cycle during labour that causes birth eventually

Answer 21

uterine contractions
foetus pushes on cervix
increase in oxytocin from maternal pituitary via nervous reflex… positive feedback causes more uterine contractions..

Question 22

how do progesterone contraception pills work?

Answer 22

high levels of progesterone cause negative feedback so hypothalamus produces less GnRH and A.pit less FSH and LH … stop ovulation

Question 23

Wild card… Male puberty… explain.

Answer 23

Hypothalamus produces GnRH, A.pit produces FSH and LH… in testes sertoli cells perform spermatogenesis and leydig cells produce testosterone