SUSHUMNA NADI (SPINAL CORD)

 

In addition to chakras, there are three important nadis i.e. Sushumna Nadi (spinal cord), Ida Nadi and Pingala Nadi. The sushumna nadi is located in backbone and it ensures the circulation of energy in the body through cerebrospinal fluid. The Ida Nadi symbolises Chandra (moon) and is located to the left of Sushumna Nadi while Pingala Nadi symbolises surya (sun) and is located to the right. The Ida represents negative and Pingala positive character. While the Sushumna acts as a balancing factor. The Chakras absorb the universal life force while the Nadis ensure circulation of energy in the body. The nervous system is an organ system containing a network of specialized cells called neurons that coordinate the actions of an animal and transmit signals between different parts of its body.

In most animals, the nervous system consists of two parts, central and peripheral. The central nervous system of vertebrates (such as humans) contains the brain, spinal cord and retina. The peripheral nervous system consists of sensory neurons, clusters of neurons called ganglia and nerves connecting them to each other and to the central nervous system. These regions are all interconnected by means of complex neural pathways. The vertebrate nervous system can also be divided into areas called grey matter and white matter. Grey matter contains a high proportion of cell bodies of neurons. Grey matter is found in clusters of neurons in the brain and spinal cord and in cortical layers that line their surfaces. White matter includes all of the nerves and much of the interior of the brain and spinal cord. Sensory neurons are activated by physical stimuli impinging on them, and send signals that inform the central nervous system of the state of the body and the external environment. Motor neurons situated either in the central nervous system or in peripheral ganglia, connect the nervous system to muscles or other effecter organs. Central neurons, which in vertebrates greatly outnumber the other types, make all of their input and output connections with other neurons. The interactions of all these types of neurons form neural circuits that generate an organism's perception of the world and determine its behaviour.

The spinal cord is a long, thin, tubular bundle of nervous tissue. The brain and spinal cord together make up the central nervous system (CNS). The length of the spinal cord is much shorter than the length of the bony spinal column. The spinal cord is connected to the brain and is about the diameter of a human finger. From the brain the spinal cord descends down the middle of the back and is surrounded and protected by the bony vertebral column. The spinal cord is surrounded by a clear fluid called Cerebral Spinal Fluid (CSF), that acts as a cushion to protect the delicate nerve tissues against damage from banging against the inside of the vertebrae. The spinal cord is about 45 cm (18 in) long in men and around 43 cm (17 in) in women, ovoid-shaped, and is enlarged in the cervical and lumbar regions.

The spinal cord is the main pathway for information connecting the brain and peripheral nervous system. The spinal cord functions primarily in the transmission of neural signals between the brain and the rest of the body but also contains neural circuits that can separately control numerous reflexes and central pattern generators. The spinal cord has three major functions: as a conduit for motor information, which travels down the spinal cord, as a conduit for sensory information in the reverse direction, and finally as a centre for coordinating certain reflexes. The anatomy of the spinal cord itself consists of millions of nerve fibres which transmit electrical information to and from the limbs, trunk and organs of the body, back to and from the brain. The brain and spinal cord are referred to as the Central Nervous System, whilst the nerves connecting the spinal cord to the body are referred to as the Peripheral Nervous System. The nerves which carry information from the brain to muscles are called Motor Neurones. The nerves which carry information from the body back to the brain are called Sensory Neurones. Sensory neurones carry information to the brain about skin temperature, touch, pain and joint position. Nerves called the spinal nerves or nerve roots, these nerves carry information from the spinal cord to the rest of the body and from the body back up to the brain.

There are four main groups of spinal nerves, which exit different levels of the spinal cord. These are in descending order down the vertebral column. Cervical Nerves (nerves in the neck) supply movement and feeling to the arms, neck and upper trunk, also control breathing. There are 31 pairs of spinal nerves which branch off from the spinal cord. The peripheral region of the cord contains neuronal white matter tracts containing sensory and motor neurons. Internal to this peripheral region is the gray, butterfly-shaped central region made up of nerve cell bodies. This central region surrounds the central canal, which is an anatomic extension of the spaces in the brain known as the ventricles and, like the ventricles, contains cerebrospinal fluid. The gray matter, in the centre of the cord, is shaped like a butterfly and consists of cell bodies of inter neurons and motor neurons. The white matter is located outside of the gray matter. “Columns” of white matter carry information either up or down the spinal cord.