(Solved): Case \#1: A woman is in labor. Positive Feedback Mechanism The slze of the fetus combined with the ...

Case \#1: A woman is in labor. Positive Feedback Mechanism The slze of the fetus combined with the contractions of the uterine muscular layer stretches the uterine wall, stimulating stretch receptors in the cervix. Signals from these receptors are conducted through nerves to the hypothalamus/posterior pituitary. The hypothalamus/posterior pituitary releases oxytocin. The oxytocin travels through the blood and stimulates the smooth muscle layer of the uterus. Oxytocin has two effects on the uferine smooth muscle: 1. It directly stimulates the smooth muscle to contract more frequently and more forcefully. 2. It causes the uterine wall to release prostaglandins, which increase the frequency and force of the contraction even more. These effects push the fotus more forcefully into the cervix, stimulating the stretch receptors further. The receptors send additional impulses to the hypothalamus/posterior pituitary. The increased activation of the hypothalamus/posterior pituitary stimulates release of additional oxytocin, which further stimulates the uterus. This cycle of activation continues until the fetus is expelled from the uterus. 1. What is the stimulus of this control loop? The pressure or stretch felt at the uterus. As when pressure is there oxytocin is released and when pressure decreases oxytocin decreases. 2. What is the sensor (receptors)? 3. What is the control center? The hypothalamus or brain 4. What is the effector? Muscles of the uterus that contract 5. This is an example of (positive / negative) feedback. How could you tell? Positive feedback because as more pressure is felt the more the baby is expelled from the uterus. 6. Is this mechanism beneficial or harmful? 7. Is the process solf-terminated or not? Explain. 8. Why this type of mechanism is rarely beneficial in our body? Why does this make sense?