The Brain, Marrow and Womb
Besides the main organs and the gut, we also have special organs like the brain, marrow, and womb. These are known as the "odd and constant" organs, different from the main organs and the gut. Each kind of organ does its own job but also connects and influences the others.
In the group of odd and constant organs, you also find bone, blood vessels, and the gallbladder. The gallbladder is unique because it is considered both a part of the gut, as we talked about before, and an odd and constant organ.
The brain is the most important of these six special organs. It's the place where all thinking happens. We call it "the organ of original spirit." The paths that marrow takes go up to the brain and down to the tailbone area. This idea is kind of like what modern Western medicine says about the central nervous system.
The brain and marrow have a strong link to the kidneys. The kidneys help the bones, the bones make marrow, and the marrow moves through the brain, which is like a "sea of marrow." So, when your kidneys are full of good energy, your brain's marrow will be full too, making you feel lively and happy. The womb in women is another word for the uterus. It's there for monthly cycles and for growing a baby. How well the uterus works relies a lot on the good energy from the kidneys.