THE LIVER STORES BLOOD: The liver is the most important organ for storing blood in TCM. It regulates the volume of blood in the whole body at any one time. There are three aspects to the Liver function of storing blood.
1. //THE LIVER REGULATES THE VOLUME OF BLOOD IN THE BODY// This is in respect to physical activity. When the body is active the blood flows to the muscles and ligaments; when the body is at rest the blood flows back to the liver. When the blood returns to the Liver at rest, it contributes to restoring the person's energy; when it flows to the muscles and ligaments, it nourishes and moistens them. When the Livers function of storing and regulating blood volume is impaired a person can become easily tired, their muscles will not be well nourished and moisturized therefore making them liable to attack by exterior pathogenic factors outside the body.
2. //LIVER BLOOD REGULATES MENSTRUATION// If the Liver stores blood normally, then menstruation will be normal. If the Liver is deficient there will be amenorrhoea or scanty periods. If there is too much blood or heat, the periods may be heavy. If the Liver blood is stagnate the periods will be painful and clotted.
3. //LIVER BLOOD MOISTENS EYES & LIGAMENTS// Liver blood moistens and brightens the eyes. If it's deficient the person may suffer from dry eyes or blurred vision. If it's deficient it there may be muscle cramps and tendon strains.

source: Foundations of Chinese Medicine