Physiology of Parturition - Dr. da Silva Flashcards
What is essential for the maintenance of pregnancy?
Progesterone
What 2 species don’t have the P4 fall prior to parturition?
Primate and Guinea Pig
In what species is the placenta the progesterone source?
Sheep, Cow, Mare, Primate, Guinea Pig
(T/F) Most studies of parturition is in sheep, primates, lab animals
True
What are the Three functions of P4?
- Development/function of the placenta through gestation
- Myometrial quiescence, keeps uterine “quiet”
- Closure of cervix, keeps it tight
(T/F) Fetus triggers parturition
True
What is the stress that the fetus undergoes, that then triggers the hypothalamic-pituitary-adrenal axis?
hypoxia
Events of Parturition
Increased Cortisol increases __________ and __________
Estrogen and PGF2alpha
- Increase Oxytocin receptors
- Increase GAP junctions uterus
- Relax cervix
Increased estrogen
- Luteolysis
- Stimulate Relaxin synthesis
- Cervix/ Ligaments - Myometrial contractions
Increased PGF2alpha
What is the most common cause of equine dystocia?
Fetal malposture
Fill in the blanks:
Events of Parturition
- Increased pressure + open cervix
- Rupture of ________________
- Release of ____________ fluid
- Further lubrication of the birth canal
- Fetus enters the birth canal
- Stretch of cervix / cranial vagina
- Increase oxytocin release
- Fergusson’s Reflex
chorioallantois, allantoic fluid
What stage of parturition is this?
- Myometrial contractions begin
- Cervical relaxation
- Fetus adopts birth posture / position
- Chorioallantois rupture
Stage I
What stage of parturition is this?
- Fetus enters the birth canal
- Strong uterine / abdominal contractions
- Fetus is delivered
Stage II
What stage of parturition is this?
- Placental expulsion
Stage III
(T/F) During parturition, stretching of the cervix stimulated Ferguson’s reflex and causes a major release of prostaglandin from the uterus
False
What event determine the end of the first stage of parturition and the initiation of the second stage?
Rupture of the allantochorion and release of allantoic fluid
During parturition, fetal stress causes the secretion of cortisol by the fetal adrenal glands. The increased cortisol causes:
- Increased secretion of PGF2alpha
- Decrease in progesterone and increase in estradiol secretion by the placenta
- Maturation of fetal lungs, kidney,s and brain
- Increase in the reproductive tract secretion
During parturition in cows, increased levels of fetal ____________ act in the placenta and uterus resulting in a rapid decrease in _____________levels and an increase in both ________________ and _____________ levels.
cortisol, progesterone, estradiol, prostaglandin
