Exam 4: Parturition Flashcards
(26 cards)
Parturition
Process by which uterus delivers the fetus and placenta
Labor
Associated with rhythmic contractions of the uterine smooth muscle
Stages of parturition
- Resumption of myometrial contractions and cervical maturation- triggered by release of progesterone block
- Expulsion of the fetus- abdominal muscles provide main strength of contractions
- Expulsion of placental tissues- due to myometrial contractions
Effects of fetal corticoids
Convert progesterone to estradiol
Effects of fetal stress
Increased fetal ACTH
Fetal Cortisol
Effects of fetal cortisol
Decreased Progesterone
Increased Estrogen
Effects of progesterone and estrogen in the ovary
Relaxin –>
Cervical dilation
Effects of progesterone and estrogen in the uterus
^ PGF2a
^ PGE
^ Oxytocin receptors
Effects of PGF2a
Luteolysis
Myometrial contractions
–>
Ferguson’s reflex
Effects of PGE
Cervical dilation
Effect of cervical dilation
Ferguson’s reflex
By presence of fetal head against the cervix
Effect of Ferguson’s reflex
Oxytocin release
Effects of oxytocin release
Bind oxytocin receptors
Stimulate PGF2a synthesis/release
More myometrial contractions
+
Abdominal contractions
–>
Delivery
Puerperium
Time elapsing from parturition to normal resumption of estrus cycles
4 events of uterine involution
Occurs during puerperium
Decreased uterine size & volume
Expulsion of lochia
Endometrial repair
4 phases of puerperium
- Myometrial contractions & release of lochia
- Endometrial repair
- Resumption of estrous cycles
- Expulsion of bacterial contamination
Dystocia
Difficult parturition
3 causes of dystocia
Fetus of large size
Abnormal positions of fetus
Multiple births in monotocous species
Tocolysis
Stop myometrial contractions
Drug: Terbutaline
Drugs to induce parturition
Corticosteroids- ruminants (can lead to retained placenta in cows)
PGs- mares & goats
Oxytocin- used to drop placenta and shrink uterus
4 adaptations of fetal circulation
- Complete oxygenation of blood in placenta
- Ductus venosus (in liver)
- Ductus arteriosus (aorta to pulmonary artery)
- Foramen Ovale (hole between left and right atria)
What is the major problem in all species in premature birth
What can be given to help
Inflation of the lungs
Steroids
Surfactant factor
Produced by lungs to decrease surface tension to allow lungs to inflate
What does colostrum provide
Passive immunity
