Wherever there is an interlacing of several nerves, arteries and veins, that centre is called Plexuses. The physical gross plexuses that are known to the Vaidya Shastra are Hepatic, Cervical, Brachial, Coccygeal, Lumbar, Sacral, Cardiac, Epigastric, Esophageal, Pharyngeal, Plumonary, Lingual, Prostatic, etc. Similarly there are plexuses or centres of Sukshma Prana in the Sushumna Nadi. All the functions of the body, nervous, digestive, circulatory, respiratory, genito-urinary and all other systems of the body are under the control of these centres in Sushumna. These are subtle centres of vital energy.
These are the centres of consciousness (Chaitanya). These subtle centres of Sushumna have their corresponding centres in the physical body. For example, Anahata Chakra which is in the Sushumna Nadi has its corresponding centre in the physical body at the heart (Cardiac Plexus).
The subtle centres in the Sushumna Nadi are otherwise known as Lotuses or Chakras. A particular Tattva preponderates at every Chakra. There is a presiding deity in each Chakra. In every Chakra a certain animal is represented. It denotes that the centre has the qualities, Tattvas or Gunas of that particular animal. There are six important Chakras: Muladhara, Svadhisthana, Manipura, Anahata, Vishuddha, and Ajna. Sahasrara is the chief Chakra. It is in the head. These 7 Chakras correspond to the Lokas (Bhuh, Bhuvah, Svah, Maha, Jana, Tapa, and Satya Lokas). Muladhara to Vishuddha are the centres of Pancha Bhutas (five elements): earth, water, fire, air and ether.
When Kundalini is awakened it passes on from Muladhara to Sahasrara through all the Chakras. At every centre to which the Yogi directs the Kundalini, he experiences a special form of Ananda (Bliss) and gains special Siddhis (psychic powers) and knowledge. He enjoys the Supreme Bliss when Kundalini is taken to Sahasrara Chakra.
