In the modern Western medical science, a spleen is the largest immune organ and the storage of blood. But in the traditional Chinese medical science, the spleen is closer to the digestive system, and secondly it is related to the circulatory system.
The active substance of a spleen is called “spleen-Qi” (脾气). The functions of a spleen, which also can be called the functions of the spleen-Qi, include: promoting the digestion and absorption of food and water, transmitting upwards nutrient substances and water, keeping the normal positions of viscera, and keeping blood in vessels.
The first function of a spleen is to promote digestion and absorption of food. The spleen can promote the stomach and the small intestine to digest and absorb nutrient substances and water. So the spleen-Qi acts as an activator of the process of digestion.
The second function of a spleen is to transmit upwards nutrient substances and water. The spleen-Qi cause nutrient substances and water to be carried to the heart and the lungs. The nutrient substances and water form blood in the heart and form Qi (气) in the lungs. Qi is the basic active substance that promotes many physiological processes of a body. If the spleen-Qi is deficient, the function of transmitting upwards will be abnormal, so the Qi and blood will be deficient, and the body will be weak.
The third function of a spleen is to keep the normal positions of viscera. The lift of the spleen-Qi can keep viscera being in their normal positions and avoid the ptosis or prolapsed of viscera. If the spleen-Qi is very deficient, it can cause gastroptosis, nephroptosis, hysteroptosis，hernia or rectocele. So in the traditional Chinese medical science, patients suffering from visceral ptosis are generally treated with the medicines of invigorating the spleen-Qi.
The fourth function of a spleen is to keep blood in vessels. The spleen-Qi can keep blood circulating in vessels and avoid hemorrhage. If the spleen-Qi is very deficient, the blood will flow out of vessels, and it will cause purpura, hematuria, intestinal hemorrhage or metrorrhagia. These types of hemorrhages also are brought by other causes such as pathological heat (also called “fire”). So it is very necessary to treat different types of hemorrhages according to syndrome differentiation. If a patient with hemorrhage is anorectic, languid and even faint, the cause of hemorrhage is the deficiency of the spleen-Qi. If a patient with hemorrhage is testy and he wants to drink cool water very much, the cause of hemorrhage is pathological heat.
Because the spleen-Qi can promote the digestion and absorption of food and transmit nutrient substances, a spleen is connected with the growth of muscle and the functions of arms and legs. If the spleen-Qi is ample, muscle will be nourished, so arms and legs will be strong. But if the spleen-Qi is deficient, muscle will lack nutrition, so arms and legs will be weak. Even the serious deficiency of the spleen-Qi can cause flaccid paralysis. Because the spleen is very important to the growth of muscle and the functions of arms and legs, the spleen is called “the maintainer of muscle” and “the maintainer of four limbs”.
The gustatory sensation is related to the spleen. If the spleen-Qi is ample, the gustatory sensation is normal, and the appetite is good. If the spleen-Qi is deficient, the gustatory sensation will be abnormal, and the appetite will be lost. Because everyone tastes food by mouth, the book “Ling Shu” (灵枢) which is one of traditional Chinese medical classics says, “The spleen-Qi opens into the mouth. So if the functions of a spleen are harmonious, the mouth can correctly distinguish the taste of different food”. The lips are also related to the spleen. If the functions of the spleen are normal, the Qi and blood are ample, so the lips are ruddy. If the functions of the spleen are weakened, the Qi and blood will be deficient, so the lips will be pallid. Because the mouth and lips are all related to the spleen, so the book “Ling Shu” says, “The mouth and lips are the organs of the spleen.”
The traditional Chinese medical science distinguishes saliva into two kinds. The thin saliva which is secreted by the parotid gland is from the spleen, and the thick saliva which is secreted by the sublingual gland is from the kidneys. The functions of the thin saliva are to moisten the oral cavity for protecting oral mucosa, to wet food for chewing and deglutition and to promote digestion. Generally the spleen-Qi is ample, and the forming and distributing of thin saliva is normal, so the thin saliva doesn’t flow out over mouth. If the spleen-Qi is deficient, the thin saliva will increase pathologically and flow out over mouth, and this is pathological salivation.
In the traditional Chinese medical science, the feelings of worry and anxiety are related to the spleen. If a person is worried too much or anxiety-ridden, his spleen-Qi will stagnate and lose activity, and the functions of the spleen will be disordered, so he will be anorectic and suffer from flatulence and vertigo.
In the ancient Western medical science, the spleen is also related to some feelings. According to the Wikipedia Encyclopedia, in French the spleen is related to the feelings of pensive sadness and melancholy. The connection between the spleen and melancholy is from the humoral theory of ancient Greek medical science. The black bile, one of the humors, is secreted by the spleen and is associated with melancholy.
The spleen is a very important organ in the traditional Chinese medical science, so the traditional doctors always advise people to take good care of the health of the spleen all along. But in the modern Western medical science, the spleen can be even removed surgically. So don’t confuse the spleen in the traditional Chinese medical science and the spleen in the modern Western medical science.