Chakras do indeed exist. There are many human names for what is perceived to be a biophysical connection to the spirit. These connections exist in that the soul, or spirit, is immersed in the physical body and mingles throughout. An incarnation is not a superficial matter. During an Out-of-Body experience the soul separates from the physical body, and the human left behind is quiescent, as though without emotion or much thought. This is a time spent quietly contemplating or doing mundane tasks. As the soul, during incarnation, is diffused throughout the body, it aligns itself to embrace the world. The soul communicates with its extensions, the human arms and legs, as this is not a natural position for the soul. Incarnations in life forms that do not have arms and legs would, understandably, have different chakras.
The chakras are related to the functions of the incarnated spirit, not to the human form. The spirit centers itself, and thus the heart chakra, and concerns itself with communicating to the mind, and thus the third eye, but the other organs of the human body are incidental to the spirit, which is not concerned with digestion or locomotion or such functions. Spirits that are more entranced with physical activities, such as sex or drug use, may be more diffuse within the physical body, however. A central chakra, both in the human body and in chakra action, is the heart chakra. There are several reasons for this. First, the heart is centralized in the human body in order to serve the body well in its task as circulation central. Second, the heart responds to emotions, invariably, beating fast during fright or joy, being regular or irregular in pace with the life situation. Third, the spiritual centering of the soul within the physical body of a human must for similar reasons be centered. As the soul fills the being of whatever it incarnates, it is distended into the human limbs and digits. To work as a unit, the soul indeed utilizes parts of itself to maintain unity and cohesive action. The heart chakra, while not circulating fluids, has a similar importance and function.