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20 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What is myometrium?
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the smooth muscle which surrounds the uterus (also contains collagen)
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What is involved in cervical ripening?
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- Breakdown of collagen in myometrium
- cervix becomes thin and begins to dilate |
occurs during labour alongside contractions
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What are the 4 stages of pregnancy?
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- quiescence
- activation - stimulation - involution |
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A rise in oestrogen causes what to OTRs?
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increase in the number of
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OTRs: oxytocin receptors
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Changes in myometrium in late pregnancy?
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increase in CAPs (contraction associated proteins)
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- increase in OT, gap junctions (imp for contractions), prostaglandin receptors
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What dos involution involve?
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shrinking of the uterus (OT does this)
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What is the function of IP3?
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Acts on SR to release Ca2+
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What is the mechanism of myometrial contraction?
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- [Ca2+]i increases and binds to calmodulin
- which activates MLCK enzyme which phosphorylates myosin which interacts with actin --> contraction |
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OT causes?
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smooth muscle contaction in uterus, milk production
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what other hormone causes milk production?
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prolactin
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What type of receptors are OTRs?
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GPCRs
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What are the 2nd messenger involved with OTRs?
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IP3 and DAg
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Prostaglandins are important for?
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contraction and relaxation
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Name 3 prostaglandins and their receptors
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PGE2, PGF2alpha, PGI2
EP, FP, IP |
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Which PGs cause contraction?
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PGF2alpha (produce IP3 increasing Ca2+) and PGE2 (decrease cAMP increasing Ca2+)
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What do oxytocics do?
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stimulate uterine contractions
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What do tocolytics do?
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inhibit uterine contractions
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MOA of oxytocics
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Binds to OTRs production of IP3/DAG --> ca2+ released from SR thus contractions
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Other than to induce contractions why else are oxytocics used?
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To keep uterus contracting after child birth to prevent blood loss (ie. post partum haemorrhage)
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Suggest some tocolytic MOAs
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- Antagonist of OTR (prevents increase in Ca2+)
- B2 agonist (increases cAMP, ca2+ reuptake into SR and inactivates MLCK) -calcium channel blockers |
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