Hormones involved in birth and lactationDiscover the hormones involved in birth and lactation. For each, indicate where it is secreted from and what its effects are. Describe whether the mechanisms involved are negative or positive. There are several different hormones that influence the female reproductive system and the two most basic hormones are progesterone and estrogen. Progesterone is a steroid hormone and has a number of physiological effects on the body, such as normalization of blood clotting and vascular tone, zinc and copper levels, oxygen levels in cells and l use of fat reserves for energy. It also contributes to thyroid function. It is usually necessary to normalize or restore changes caused by estrogen. It affects all aspects of pregnancy, preparing the breasts for lactation and the relaxation of joints and ligaments in preparation for childbirth. It can affect bowel movements, usually causing constipation and back pain and increasing body temperature. Estrogens are a group of steroid compounds that function as the primary female sex hormone. Developing follicles in the ovaries, corpus luteum and placenta primarily produce them and some secondary sources in smaller quantities can be found in the liver, adrenal glands and breasts. Although estrogen is present in both men and women, it is significantly higher in women and is involved in controlling the menstrual cycle. Like progesterone, estrogen also affects all aspects of pregnancy and is especially important for maintaining the health of the genital tract, reproductive organs, and breasts. because breastfeeding is no longer necessary, lactation will usually cease after one to two weeks. High levels of prolactin also tend to suppress the ovulatory cycle by inhibiting FSH. Oxytocin also plays a role in lactation, as it is this hormone that stimulates myoepithelial cells causing the ejection of milk into the ducts of the mammary glands. Sucking on the nipple by the baby again will stimulate the release of oxytocin. In this case, the release of oxytocin and prolactin are controlled by negative feedback, unlike the release of oxytocin during childbirth. Based on information from: 1. Biology, a functional approach by MBV Roberts, 4th edition2. http://en.wikipedia.org/wiki/lactation3. Pregnancy and Birth by Miriam Stoppard published 1986* * * * *