The nervous system includes:sensory organs, spinal cord, and nerves that connect to the rest of the body.It has two main parts, the central nervous system and the peripheral nervous system.It sends messages back and forth between the brain and body.It contains specialized cells called neurons that make up nerves.Also regulates internal organs and various body processes, such as blood pressure. There are 1 billion neurons in the spinal cord, the brain uses 20% of the body’s energy. Parts of the neurons are the Axon, Cell Body, Dendrite and the synapse.The brain takes up half of the inside of the head.It is also well protected from knocks and bumps by the curved bones of the skull.There are 12 pairs of nerves that join directly to the brain that are called crainial nerves. They branch out mainly to the head, face, and neck. The spinal cord is the brains main link with the rest of the body. From the cord, 31 pairs of spinal nerves branch outward, into the body.The spinal nerves break up into branches as well.The two main parts of the nervous system are the Central nervous system and the Peripheral nervous system.The central nervous system does many things like: receiving the information and it also makes the decisions in the body as well as transmitting the instructions to all the parts in the body.This is also a network of nerves connecting to the central nervous system to all the sensing receptors all over the body.The body parts are all a speaking to each other but it doesn’t make decisions for the body.This is also a network of nerves connecting to the central nervous system to all the sensing receptors all over the body. In my opinion I think it is a speaking system that talks to everyone but it doesn’t make decisions for the body.The cranial nerves are the 12 pair of nerves that are : optic nerve, oculomotor, trochlear, trigeminal, abducens, facial, vestibulocochlear, glossopharyngeal, vagus, accessory, hypoglossal, olfactory.The olfactory nerve conveys sensory information to the brainThe optic nerve brings visual information to the brainThe oculomotor, trochlear, and abducens nerves take over the extraocular muscles, basically the muscles that move your eyesThe trigeminal nerve carries somatosensory information from the face and head to the brain.The facial nerve: it carries or sends taste information from the front of the tongue and the floor of the mouthThe vestibulocochlear nerve:a sensing nerve that consists of two places that control hearing and balance.The glossopharyngeal nerve:also takes taste information.The vagus nerve: is the only cranial nerve that reaches beyond the head and neckThe spinal accessory and hypoglossal nerves: are both motor nerves that control.The body is made up of billions of little cells of many different shape and sizes. Bone cells make bones, muscle cells form muscles, and liver cells make the brain and the nerves. The nerve cells are also called neurons,the main part though of the nerve cell is the cell body but it is also similar to the other cells, when it is seen under the microscope. It has tiny parts inside it, such as the nucleus, which is the control center,and the mitochondria to provide the energy.They usually also around the cell body are lots of spidery-looking parts which are called dendrites which are the nerve fiber.