Hormones Involved in Birth and Lactation

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Hormones Involved in Birth and Lactation

Find out about the hormones involved in Birth & Lactation. For each

one, state where it is secreted from and what its effects are.

Describe whether the mechanisms involved are negative or positive

feedback.

There are several different hormones that influence the female

reproductive system and the two most fundamental hormones are

progesterone and oestrogen. Progesterone is a steroid hormone and has

a number of physiological effects on the body such as normalising

blood clotting and vascular tone, zinc and copper levels, cell oxygen

levels, and the use of fat stores for energy and it also assists in

the thyroid function. It is usually required to normalise or restore

changes caused by oestrogen. It affects all aspects of pregnancy,

prepares breasts for lactation and the relaxation of joints and

ligaments in preparation of childbirth. It can affect bowel movements

usually causing constipation and back pain and raises the body

temperature.

Oestrogens are a group of steroid compounds that function as the

primary female sex hormone. Developing follicles in the ovaries, the

corpus luteum and the placenta primarily produces them and some

secondary sources in smaller amounts can be found in the liver,

adrenal glands and breasts. Although oestrogen is present in both male

and females, it is found to be significantly higher in women and is

involved in controlling the menstrual cycle. As does progesterone,

oestrogen also affects all aspects of the pregnancy and is

particularly important in maintaining the health of the genital track,

the reproductive organs and the breasts.

Throughout ...

... middle of paper ...

...en the demand for breastfeeding is no more the

lactation will usually cease with one to two weeks. High prolactin

levels also tend to suppress the ovulatory cycle by inhibiting FSH.

Oxytocin also plays a role in lactating, as it is this hormone that

stimulates the myoepithelial cells causing the milk to be ejected into

the ducts of the mammary glands. Suckling by the baby on the nipple

again will stimulate oxytocin release. The release of oxytocin in this

instance, and prolactin are controlled by negative feedback unlike the

release of oxytocin during childbirth.

Based on information taken from:

1. Biology a Functional Approach by MBV Roberts, 4th Edition

2. http://en.wikipedia.org/wiki/lactation

3. Pregnancy and Birth by Miriam Stoppard Published 1986

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