Connecting the Feet, Spinal Cord, and Brain
The central nervous system is the brain, the brain stem, and the spinal cord. The basic functional unit in the CNS is the neuron. Electrical impulses are chemically transmitted across synapses to other neurons, creating a pathway. The CNS integrates incoming information, generates thoughts and feelings, and stores memories. The impulse for muscles to contract and glands to secrete comes from the central nervous system.
The Peripheral Nervous System (PNS)
Once the neurons move into the peripheral area of the nervous system, they become nerves. The peripheral nervous system connects the CNS to sensory vehicles, muscles, and glands. The peripheral nervous system is composed of cranial and spinal nerves. These nerves carry information in and out of the central nervous system. Sensory neurons carry information from sensory receptors in the body into the CNS, while motor neurons carry impulses out of the CNS to the muscles and glands.
Somatic and Autonomic Nervous Systems
The peripheral system can be further divided into the somatic and autonomic nervous systems. The somatic nervous system (SNS) carries information from sensory receptors in the head, body frame, and limbs to the brain. Information dealing with movement travels from the brain via motor receptors to skeletal muscles. The autonomic nervous system (ANS) conveys sensory information from the organs to the CNS while motor neurons carry information from the brain to smooth muscle, glands, and the heart muscle.
A further division occurs in the motor section of the autonomic nervous system. These two areas are the sympathetic and the parasympathetic sections of the nervous system. The sympathetic section expends energy, speeding up activities, such as increasing the heartbeat. The parasympathetic component conserves energy, slowing down the heartbeat.
The nerves of the spinal cord connect the central nervous system to the operations of the body. Remember, these nerves are part of the peripheral nervous system. There are 31 pairs of spinal nerves emerging out of the bones that house the spinal cord. (The bones form a column called the vertebral column.) These nerves travel out over the entire body, connecting with all the operating systems.
One branch of the nerves found in the feet stems from the largest nerve in our body, the sciatic nerve. The sciatic nerve consists of two nerves, the tibial and the common peroneal. These nerves are tied together by connective tissue. The sciatic nerve sends its two branches down the leg into the foot. In the foot these nerves branch out again, with many divisions nourishing the entire area.