Changes

===Foetal Circulation===

===Foetal Circulation===

Prior to birth the foetus is not capable of cadiovascular function and thus is relies on the maternal circulation to carry out gas, nutirent and waste exchange. The foetal and maternal blood never mix, instead they interface at the [[Gestation -Placenta - Anatomy & Physiology|placenta]]. Consequently the liver and the lungs are not required function either and a series of shunts exist in the foetal circulation so that these organs are almost completely bipased  

Prior to birth the foetus is not capable of respiratory function and thus relies on the maternal circulation to carry out gas, nutrient and waste exchange. The foetal and maternal blood never mix, instead they interface at the [[Gestation -Placenta - Anatomy & Physiology|placenta]]. Consequently the liver and the lungs are non-functioninal, and a series of shunts exist in the foetal circulation so that these organs are almost completely by-passed.  

====Shunt 1: The Ductus Venosus====

====Shunt 1: The Ductus Venosus====

Oxygenated blood travels from the placenta via the umbilical vein and most of it bypasses the [[Liver - Anatomy & Physiology|liver]] by way of the ductus venosus. The ductus venosus links the umbilical vein to the caudal vena cava and the flow of blood is controlled by a sphincter, enabling the proportion travelling to the heart versus the [[Liver - Anatomy & Physiology|liver]] to be altered.

Oxygenated blood travels from the placenta via the umbilical vein and most of it bypasses the [[Liver - Anatomy & Physiology|liver]] by way of the ductus venosus. The ductus venosus links the umbilical vein to the caudal vena cava and the flow of blood is controlled by a sphincter, enabling the proportion travelling to the heart via the [[Liver - Anatomy & Physiology|liver]] to be altered.

====Shunt 2: The Foramen Ovale====

====Shunt 2: The Foramen Ovale====