The nervous system is complex and made up of billions and billions of nerve cellsThe nervous system is complex and made up of billions and billions of nerve cells

The nervous system is complex and made up of billions and billions of nerve cells. This unit takes in signals from your senses and processes the information, leading to a reaction response by muscles and glands. For instance, if you scrape your arm, nerve cells will send a signal to the muscles in your arm and make you feel pain if you get hurt. The human brain has about a hundred billion nerve cells known as neurons. There are two parts of the nervous system; the central and the peripheral nervous system. The central nervous system oversees the brain and spinal cord. The peripheral nervous system is made up of nerve fibers that extend from the spinal cord to other parts of the body.
Some functions in the nervous system are involuntary, which means that you do not consciously control them. The involuntary system regulates your breathing, heartbeat and other processes, that just means it is constantly operating. When your bladder is full, and you must use the bathroom, it is the involuntary system that lets our brain recognize these signals. The cerebral cortex has three main activities: mental, sensory, initiation, and control. The mental activities are involved in thinking, memory, intelligence, reasoning, learning, sense of responsibility, and moral sense. Sensory perception includes the perception of temperature, pain, sight, hearing, touch, smell, and taste. Lastly, the initiation and control process is to induct and control voluntary muscle contraction.
There are four groups of nerves that come from the thoracic, lumbar, sacral, and cervical regions of the spinal cord which is the peripheral nerves. The peripheral nervous system is subdivided into a motor division and a sensory division. The motor neurons will transmit impulses from the central nervous system into the peripheral organs to cause an effect or action. Sensory neurons will transmit impulses from the peripheral organs to the central nervous system. Interneurons are the most multipolar, they connect sensory and motor neurons together. The sympathetic division mobilizes the body systems during any activity and the parasympathetic division conserves energy.
The brain is the source of all thoughts, feelings, and behavior. It is divided into three parts, the hindbrain, midbrain, and the forebrain. Therefore, this has a lot to do with most of the controls of the body such as; analysis of sensory data, reinforce motor impulses, and all the muscle and gland activity. The spinal cord is made up of nerve fibers that send information to the brain to process and interpret it.