What is placenta ? Give information about hormones producing from the placenta.

After implantation, finger-like projections appear on the trophoblast called chorionic villi which are surrounded by the uterine tissue and material blood.

The chorionic villi and uterine tissue become interdigitated with each other and jointly form a structure and functional unit between developing and embryo (foetus) and maternal body called placenta.

Function of placenta : The placenta facilitate the supply of oxygen and nutrients to the embryo.

It also facilitate the removal of carbon dioxide and excretory material produced by the embryo.

The placenta is connected to the embryo through an umbilical cord which helps in the transport of substances to and from the embryo.

Hormones produced from placenta : Placenta also acts an endocrine tissue and produces several hormones like: 

$(i)$ Human chorionic gonadotropin ($hCG$)

$(ii)$ Human placental lactogen ($hPL$)

$(iii)$ Estrogens

$(iv)$ Progestogens

$(v)$ In the later phase of pregnancy a hormone called relaxin is also secreted by ovary.

$(vi)$ $hCG$, $hPL$ and relaxin are produced in women only during pregnancy.

$(vii)$ During pregnancy the levels of other hormones like estrogens, progestogens, cortisol, prolactin, thyroxine etc. are increased.

These hormones are essential for supporting the fetal growth, metabolic changes in the mother and maintenance of pregnancy.