Questions Flashcards
Hormone production is by the?
placenta, foetus and pregnant person continue to change throughout the pregnancy
What are the 6 hormones in pregnancy?
- produce
- function
- what does it inhibit?
- Human Chorionic Gonadotropin
- is produced by the placenta after implantation.
- It supports the function of the corpus luteum, a temporary structure in the ovaries essential in early pregnancy.
- It’s the hormone detected by pregnancy tests. - Progesterone
- helps establish the placenta
- stimulates the growth of blood vessels that supply the womb and inhibits contraction of the uterus so it grows as the body does
- strengthens pelvic wall muscles for labour - Oestrogen
- helps the uterus grow, maintains its lining, and helps foetal organs develop
- activates and regulates the production of other hormones
- with progesterone stimulates breast growth and milk duct development - Prolactin
- is the main hormone needed to produce breast milk
- it contributes to enlargement of the mammary glands and prepares them for milk production
- inhibits lactation during pregnancy - Relaxin
- inhibits uterus contraction to prevent premature birth
- it relaxes blood vessels, increasing blood flow to the placenta and kidneys
- it relaxes the joints of the pelvis and softens and lengthens the cervix during birth - Oxytocin
- levels rise at the start of labour, stimulating contractions of uterine muscle
- it triggers the production of prostaglandins, which increases contractions further
- labour doesn’t start naturally, it can be used to induce it
what expands during pregnancy?
not just the uterus, but the entire abdominopelvic cavity must expand (and reorganize) to accommodate
What are the other pregnancy-related strains?
- they are mainly physiological, mainly based on increased metabolic requirement
- Maternal respiratory rate and tidal volume increases
- Mammary glands are fully developed nu the end of the sixth month of pregnancy
- Maternal glomerular filtration rate (GFR) increases by nearly 50%
- Bc/ the volume of urine produced increases and the weight of the uterus presses down on the urinary bladder, reg women need to urinate frequently
- Maternal blood volume increased by almost 50% by the end of gestation
- Maternal requirements for nutrients increase by up 30% above normal
- The uterus expands from 7-5 cm to 30 cm in length from 30 - 40g in weight to 1100g. this expansion occurs through hypertrophy of existing cells
Labour and delivery involve?
dilation of the cervix and propulsion of the foetus into the birth canal (vagina)
What happens during late pregnancy (specifically the uterine smooth muscle cells)?
-How?
- Why?
- switch to single-unit (gap junction-coupled) organization
- Begin to express oxytocin receptors
How?
- these changes are due to prolonged exposure to elevated estrogen (secreted by the placenta)
Why?
- single-unit organization enables the entire myometrium to contract and relax in synchronized waves
What happens during true labour?
- what does it center around?
- Why?
- Analogy
True labour: every part of the uterus is contracting
- true labour centers around the initiation of regular rhythmic contraction of the uterine myometrial layer
- Synchronised wave contractions are stronger and more effective at producing pressure on the cervix
- tug-a-war you create more force when everyone is pulling together and affectively more things
Labour is initiated by placental and foetal factors (test yourself on the red boxes on the chart).
lecture #24 slide 14
Labour is enhanced by maternal factors, including..?
oxytocin (good at making contraction but not starting rhythmic contraction), in a positive feedback loop
What happens during a positive feedback loop?
Mechanical stimulation of cervical tactile neurons triggers maternal oxytocin release = further enhances contractions = pressure on the cervix = increasing cervical dilation
What are the steps of a positive feedback loop?
- The head of the baby pushes against the cervix
- Nerve impulses from cervix transmitted to the brain
- The brain stimulates pituitary gland to secrete oxytocin
- Oxyocin carried in the bloodstream to the uterus
- Oxytocin stimulates uterine contractions and pushes the baby towards the cervix
What methods are there to induce or accelerate labour?
- medical induction methods
- Labour Enhancement/Acceleration
-> intravenous oxytocin (only given after regular contractions have begun)
What are the 3 phases, resulting in parturition (delivery)
- Dilation stage:
->Cervix dilates to about 10cm in diameter
-> In order for the baby’s head to get through - Expulsion Stage
-> Uterine contractions, supplemented by voluntary pelvic and abdominal contraction
-> You can now push - Placental Stage
-> Continued uterine contractions dislodge the placenta
-> The placenta needs to come out
What happens to the hormone milieu of any ex-pregnant person changes rapidly after parturition?
Without the placenta (removed after labour), estrogen and progesterone levels in a recently pregnant person decline precipitously. This change usually is noticeable around day 3 post-partum (3 days after the notice of the loss of hormone)
Rapid loss of placental hormones has physiological consequences, such as?
- onset of lactation
- in late pregnancy, progesterone inhibits the rise in prolactin from stimulating milk production
