Lecture 11 Flashcards
(18 cards)
What are the 3 stages of parutrition
Stage I: preparation of the birth canal
Stage II: delivery of foetus
Stage III: delivery of the placenta
How is parturition timed
By foetus via cortisol form adrenals
What ration does cortisol increase
Oestrogen:progesterone ratio which stimulates the release of prostaglandins
What do prostaglandins influence (3)
Parturition, myometial contraction and cervical ripening
What changes occur in the lungs as parturition approaches
- Surfactant enables alveoli of the lungs to remain open
What stimulates synthesis of surfactant
Rising foetal corticosteroids
What is surfactant
A phospholipid attached to an apoprotein
What is the cervix made up of
CT and smooth muscle
What ripens the cervix
Oestrogen, prostaglandins and relaxin
What are inflammatory cytokines produced by
Placenta and cervial fibrocytes
What do inflammatory cytokines attract and activated neutrophils to release (3)
- Metalloproteinases
- Collagenases
- Elastase
What do enzymes and PGE2 act to do?
Soften collagen fibres and dilate cervix
What does myometrial contractions and the foetus pushing against the cervix lead to
Further dilation
What effect does relaxin have of the cervix (3)
- Causes cervical softening and relaxation of pelvic ligaments and maternal pubic symphysis
- Promotes growth and development of mammary tissue
- Inhibition of myocetrial contractions
What plays an important part in uterine contractions
Prostaglandins
Oxytocin
What do contractions of the myocetrial cells depend on
Movement of calcium into the cells
What does oxytocin directly increase
Influx extracellular calcium
How does preparation for birth occur (2)
- initiation of uterine contractions
2. Dilation of the cervix
