The Second Trimester

The Second Trimester - of oxytocin and prostaglandins ,...

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The Second Trimester The fetus increases in size during this trimester, and bony parts of the skeleton begin to form. Fetal movements can be felt by the mother. The Last Trimester During this trimester the fetus increases in size. Circulatory and respiratory systems mature in preparation for air breathing. Fetal growth during this time uses large parts of its mother's protein and calcium intake. Maternal antibodies pass to the fetus during the last month, conferring temporary immunity. Birth Birth is a positive feedback hormonal mechanism. During birth the cervix dilates to allow passage of the fetus. Uterine contractions propel the fetus through the birth canal, usually head first. Hormonal control of the birth process involves the release
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Unformatted text preview: of oxytocin and prostaglandins , which are stimulated by uterine contractions, which stimulate more hormones that cause more contractions. ...etc. First Stage The first stage of birth lasts from beginning of contractions to the full (10 cm) dilation of the cervix . Membranes of the amniotic fluid rupture, lubricating the vagina. Second Stage Strong uterine contractions of a minute in duration separated by two to three minute intervals propel the fetus down the birth canal. Abdominal muscles relax in synchrony with the uterine contractions. Third Stage After delivery of the baby, the umbilical cord is clipped and cut. The placenta (or afterbirth) in expelled through the vagina....
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This note was uploaded on 11/29/2011 for the course BIO BSC1010 taught by Professor Gwenhauner during the Fall '10 term at Broward College.

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