The heart is the leader of all the organs and its functions reflect a person's intellectual and spiritual activities. The dysfunction of the heart can endanger all the other organs. The circulation of the blood and the heart are very closely related. The “Nei Jing” (ancient Chinese Medical Classic) states that the blood belongs to the heart. The appearance of a persons face indicates the functions of the heart, and the tongue is the “window” which shows the function of the heart. The conical sac of membranes that encloses the heart is called the pericardium. Hence, the “evil” (vicious chi) reaches the pericardium before it reaches the heart. Pericardium dysfunction will cause dysfunction of the heart.
When the yang energy of the heart is deficient, one will be weak, nervous and memory will decline. When the yin of the heart is deficient one will feel easily excited, have insomnia and have night sweating. Mucus in the heart will cause fainting, abnormal actions, and madness. When heat is in the pericardium it may also cause delirium (incoherent speech). When the blood in the heart is deficient (anemia) one will be nervous, weak, and pale.
If there is too much fire of the heart, one will feel restless, be unable to sleep soundly, and have infections of the mouth and tongue. When the chi of the heart is very weak, one will be very nervous, short of breath, and have pain in the chest as well as sore arms. Because of the relationship of yin and yang, the dysfunction of the small intestine can affect the function of the heart and vice versa.
The liver is the largest gland in the body and is located at the right part of the abdominal cavity. Its main functions are to store and adjust the blood of the body, to nourish the tendons, help joint movements, and to normalize emotional conditions. The chi of the liver is like the spring, spreading and growing. If the chi of the liver is weak, a person can be timid and indecisive. The dysfunction of the liver can make a person easily angered, fearful, and over aggressive. The heart circulates the blood and the liver adjusts the amount of blood in the circulation. When sleeping, a lot of blood will be stored in the liver. If the liver cannot perform this function one will not sleep well and nightmares and insomnia will result.
The reflection of the liver is in one's nails. The eyes are the windows of the liver. The liver nourishes the tendons. A strong liver produces strong fingernails. A weak liver produces weak, colorless, cracked nails
The functions of the spleen are transforming and transferring the essence of food and to eliminate waste. The spleen and stomach are the foundations of life. The energy supplies of life are generated from the functions of the spleen and stomach. The spleen also helps transfer fluid, to dissolve mucus, to enable the chi to control blood flow and to feed and nourish the flesh and the four limbs. The dysfunction of the spleen will cause a shortage of energy for the body, insufficient fluid control and blood flow, loss of muscle tone, discoloring of the complexion, and sluggishness of the limbs. The window of the spleen is the mouth (lips); they reflect the condition of a healthy spleen.
The lungs main function is breathing. “Chi” begins in the lungs. We breath all the time to live, and the lungs continuously intake oxygen and output carbon dioxide. (The Tai Chi breath is an example of how this function helps us to replenish, nourish, and strengthen our lungs). If the heart and lung functions are well coordinated then all the functions of the body are normal, otherwise one is sick.
The function of the lungs is to eliminate the excess fluids of the body. The color of the skin and body hair reflects the condition of the lungs. The dysfunction of the lungs is reflected by dry, lifeless skin. The nose is the window of the lungs. The large intestine and lungs form a yin yang relationship.
The main function of the kidneys is to store the chi (dynamic energy, force, or origin of life) to produce bone marrow, fulfill the function of hearing, and balance the body fluid metabolism. The chi of the kidneys reflects the growth of a human being from childhood to old age. When one's kidney chi is maturing one will have sexual drive. The functions of the kidneys produce bone marrow to help feed and fill the bones. These functions are strong when one is young, ones hair is beautiful and one will have physical strength, flexibility, and an alert mind and strong spirit. When the hair turns white and falls, it indicates that the functions of the kidneys are declining. The dysfunction of the kidneys can cause deafness, impotence, inability to bear children and the inability to balance the metabolism of body fluids and blood poisoning.
The kidneys and urinary bladder form a yin-yang relationship. The ears are the windows of the kidneys.