Yang collaterals: Branches of channels that move upward in the shallow of the body.
Yin collaterals: Branches of channels that move downward in the depths of the body.

1. Gluttony produces fullness of the stomach and intestines and is associated with irregular habits.
2. The strain of excessive labor causes injury to the collaterals.
3. If the yang collaterals are hurt, blood flows outward.
4. Inward flowing blood, due to injury of the yin collateral will beget symptoms such as bleeding stools. Doctor, there's blood in my stools.
5. Blood flows to the outside of the intestines when harm is done to the collaterals of the stomach and intestines. Oh, my belly aches!
6. It then condenses with the body secretion. When the cold evil intrudes and remains there, the stagnant mass grows with time.
More information, please read Eight Extraordinary Vessels.