02 Reproduction in Lower and Higher Animals - part 12 - Placenta

02 Reproduction in Lower and Higher Animals - part 12 - Placenta


Placenta: 

  • It is a flattened, discoidal organ in the uterus of a pregnant woman. 
  • The placenta is a temporary structural and functional connection between foetal and maternal circulation. 
  • The placenta facilitate the supply of oxygen and nutrients and also for removal of carbon dioxide and excretory wastes produced by the foetus. 
  • The placenta is attached to the wall of the uterus and to the baby's umbilical cord.
  •  Placenta is the only organ, which is formed of tissues from two different individuals- the mother and the foetus. 
  • Part of the placenta contributed by the foetus is called the foetal placenta and it is the chorionic villi. 
  • The other part which is rich in blood supply shared by the mother. It is a part of uterine wall, termed as maternal placenta. 
  • So human placenta is called haemochorial. 
  • The umbilical cord is formed of three blood vessels. Of these three blood vessels, two are small arteries which carry blood towards the placenta and one is a large vein which returns blood to the foetus. 
  • The placenta also acts as an endocrine tissue and produces hormones like hCG, progesterone, estrogen while relaxin is secreted by the ovary in the later phase of pregnancy.
  • Level of hCG increases upto the end of first trimester and then it declines. 
  • By the end of first trimester progesterone is produced by placenta. These hormones are required for foetal growth and maintenance of pregnancy.
Know The Institue : 
  • Cord blood bank, Kolkata India's first Government-run cord blood bank at Kolkata was established in 2001 and is accredited by AABB (American Association of Blood Bank). 
  • The cord blood bank functions occording to the central and state government policies, rules and guidelines. 
  • Cord blood (umbilical cord blood) is the blood that remains in the umbilical cord and placenta, post delivery. 
  • Cord blood banking is the process of collecting the cord blood, extraction and cryogenically preserving for its stem cells and other cells of the immune system for future potential medical use. 
  • Cord blood is rich in stem cells that can transform into all sorts of blood cells. 
  • They can be used to treat diseases that harm the blood and immune system e.g. leukemia, certain cancers, sickle cell anemia and some metabolic disorders.


Always Remember :

  •  hCG, HPL (Human placental Lactogen), relaxin are produced in women only during pregnancy.



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