Flashcards in Physiology of Pregnancy and Labour Deck (57)
List the cell stages a fertilised ovum goes through before implantation
Cleavage (4-cell/8-cell stages)
During which days following fertilisation does the blastocyst enter the uterus?
During which days following fertilisation does the blastocyst attach to the lining of the uterus?
Which surface cells help the blastocyst penetrate and adhere to the endometrium?
By what day following fertilisation does the blastocyst become fully buried in the endometrium?
Which tissue is the placenta derived from?
Trophoblast and decidual tissue
How is the placental cavity formed?
Trophoblastic cells differentiate into syncitotrophoblasts which invade the decidua of the endometrium to form cavities filled with maternal blood
How does the embryo communicate with the placenta?
Placental villi containing capillaries
There is no direct contact between foetal and maternal blood. True/False?
By which week of pregnancy are the foetal heart and placenta fully functional?
HCG stimulates the corpus luteum to secrete what hormone?
Oxygen-saturated blood goes to the foetus via which vessel?
Oxygen-poor blood goes from the foetus to the mother via which vessels?
What 3 factors increase the supply of O2 to a foetus?
Foetal Hb has increases carrying capacity
Higher Hb concn in foetal blood
Foetal Hb can carry more O2 in low PCO2 (Bohr effect)
Drugs can cross the placental barrier - list some teratogens
What is the effect of human chorionic somatomammotropin (HCS)?
Decreases insulin sensitivity of mother
Protein tissue formation
What effect does progesterone have on uterine contractility?
What effect does oestrogen have on the uterus?
Increases size of uterus
Relaxation of ligaments
What happens to the cardiac output during pregnancy?
Increases to cope with demands of uteroplacental circulation
Can be up to 50% above normal around 24wks!
When does cardiac output typically decrease in pregnancy?
Last 8 weeks due to uterus compressing vena cava
What happens to Hb levels during pregnancy? What is the consequence?
Decrease due to dilution of blood
Require iron supplements
What effect does progesterone have on CO2 levels?
Stimulates brain to lower CO2 levels by increasing respiratory rate
What is pre-eclampsia?
Pregnancy-induced hypertension and proteinuria
Taking folic acid during pregnancy reduces the risk of what?
Neural tube defects
Taking vitamin B during pregnancy helps what?
Make red blood cells (erythropoeisis)
Taking vitamin K before birthing prevents what?
Intracranial bleeding during labour
Towards the end of pregnancy, how does the ratio of oestrogen:progesterone change?
Ratio increases - oestrogen promotes contractility
Which hormone secreted from the posterior pituitary helps stimulate contractions in labour?
Give an example of positive feedback from the foetus that increases contractility during labour
Cervical stretch due to foetus head
N.B. also increases oxytocin release