X hits on this document

106 views

0 shares

0 downloads

0 comments

26 / 34

CHAPTER 22: THE REPRODUCTIVE SYSTEMS

VII.HORMONES OF PREGNANCYSee Fig 22.37 and 22.38, page 917.

A.Estrogens and Progesterones:

1.from corpus luteum through month 3:

a.relatively low levels;

b.maintain uterine lining during pregnancy (i.e essentially needed for the continued attachment of the embryo/fetus.)

c.prepare mammary glands to secrete milk.

2.from placenta (chorion) from month 3 until birth:

a.extremely high levels;

b.maintain pregnancy;

c.develop mammary glands for lactation.

2.Human Chorionic Gonadotropin (hCG) from chorion of placenta:

1.stimulates continued secretion of estrogens and progesterones by the corpus luteum (mimics LH);

2.can be detected by Day 8;

3.peaks at about Week 9;

4.decreases sharply during fourth and fifth month;

5.may be the cause of "morning sickness".

C.Human Chorionic Somatomammotropin (hCS) or Human Placental Lactogen (hPL) from chorion:

1.secretion starts about Day 8;

2.Levels increase as size of placenta increases;

3.peaks at Week 32 and remains at that level;

4.Effects include:

a.development of breast tissue for lactation;

b.deposition of protein in tissues;

c.regulation of metabolism:

decreases use of glucose by mother, leaving more available to fetus;

releases fatty acids from fat deposits, providing an alternative source of energy for the mother's metabolism.

D.Relaxin from the placenta and ovaries assists in delivery.

1.relaxes pubic symphysis and ligaments;

2.dilates uterine cervix.

E.Inhibin from the ovaries:

1.inhibits secretion of FSH.

Document info
Document views106
Page views106
Page last viewedSat Dec 10 08:04:54 UTC 2016
Pages34
Paragraphs725
Words5435

Comments