VGO-0141
QUESTION
In the parturition process?
OPTIONS
(A) The oxytocin increase is followed by prostaglandin increase
(B) The oxytocin increase is preceded by prostaglandin increase
(C) Oxytocin and prostaglandin act simultaneously
(D) None of the above
ANSWER
(A) The oxytocin increase is followed by prostaglandin increase
EXPLANATION
During parturition in large ruminants, stretching of the cervix and vagina by the fetus activates the Ferguson reflex, causing release of oxytocin from the posterior pituitary. Oxytocin strengthens myometrial contractions and also stimulates the uterus to release prostaglandins, especially PGF₂α, which further augment uterine contractions. Thus, in this positive-feedback phase of parturition, the rise in oxytocin is followed by an increase in prostaglandin release. Therefore, option (A) is correct. Option (B) reverses this sequence in the context intended by the question, while option (C) does not describe the sequential hormonal response emphasized in parturition.
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Veterinary Gynaecology and Obstetrics · 240 Questions