what is the function of 

1) Eustachian valve,2) Thebesian valve

3) Foramen of ovalis 4)Blue baby

• The inferior vena cava returns the blood from the lower half of the body and opens into the lowest part of the atrium and guarded by a rudimentary valve - Eustachian Valve.

• The coronary sinus opens into the atrium and returns blood from the substance of the heart and is protected by a semicircular valve – the Valve of Thebesius.

• The Foramina Ovale is a hole between the left and right atriums. Through the Foramina ovale, the blood from the inferior vena cava passed directly to the left atrium.  It closes at birth and then the blood no longer passes through the fetal foramen ovale. 

• If a foramen ovale remains open, it allows unoxygenated blood to mingle with oxygenated blood and one of several types of "blue baby" results. A blue baby is an infant born with a type of congenital heart disease that induces a bluish tinge to the skin.

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