Liver is the Hub of blood: its storage, cleansing, distribution to all other organs. It has a little assistant gallbladder (胆).
“Liver” opens door to outside world at “Eyes”: 肝开窍于目。
Liver & gallbladder are buddies “表里”关系 (Inner-outer relationship.)。One sick would affect the other.
Other such “表里” relationships:
Skin and Lung: before Ashma attack, skin problem worsen.
Liver patients have jaundice.