Signals for parturition originate fromA) Both placenta as well as fully developed foetusB) Oxytocin released from maternal pituitaryC) Placenta onlyD) The fully developed foetus only

The signals for parturition, or childbirth, originate from both the placenta and the fully developed fetus.

Step 1: Understanding the process of parturition Parturition is the process of childbirth. It is a complex process that involves several physiological changes and signals from both the mother's body and the developing fetus.

Step 2: Role of the placenta The placenta, an organ that connects the developing fetus to the uterine wall, plays a crucial role in parturition. It produces hormones such as progesterone which helps to maintain the pregnancy. Towards the end of the pregnancy, the level of progesterone decreases which is a signal for the onset of labor.

Step 3: Role of the fully developed fetus The fully developed fetus also plays a role in signaling the onset of labor. As the fetus matures, it produces more cortisol hormone. This increase in cortisol triggers the production of prostaglandins, which are hormones that stimulate contractions in the uterus.

Step 4: Role of oxytocin Oxytocin, a hormone released from the maternal pituitary, also plays a role in parturition. It stimulates contractions in the uterus. However, it is not the initial signal for parturition.

So, the correct answer is A) Both placenta as well as fully developed fetus.