Question

In the first and second trimester of pregnancy the uterus is relatively unresponsive to oxytocin but during the last weeks of pregnancy becomes increasingly responsive (meaning it will cause contractions). With your understanding of how cells respond to hormones, explain why this is the case. You must include in general how the cells change as well as the specific hormone(s) that trigger the change.

Answer 1

Oxytocin is a hormone secreated by pituitary gland and produced by hypothalamus.This hormone stimulate teh utrine muscles to contract during labour.

When the cells express a specific receptor for the hormone, the cell responds to the hormones.There will be an activation of a signal transduction mechanism that leads to cell type specific response happens when a hormone binds to the receptor protein.Hormones activate target cells by diffusing through the plasma membrane of the target cells.Not all the cells will respond to the hormoneswhile all are exposed in the blood stream.Only target cells of that hormone will only respond to its signal.

Oxytocin are effected by the myoepithelial cells of the mammary alveoli.Contraction of the myoepithelial cells will occur due to the stimulation of oxytocin and causes the milk to eject into the ducts.Stimulation of uterine smooth muscle causes the contraction at the time of birth.