The Nervous System
The nervous system is an organized group of cells specialized for the conduction of electrochemical stimuli from sensory receptors through a network. (1) Every living thing has a nervous system and can be able to detect changes around by the help of the six senses which are connected to the nervous system. The nervous system also determines the position of organs. The survival of organisms depends on the efficiency of the working of the nervous system. (1) Normally, nerves transmit impulses electrically in one direction—from the impulse-sending axon of one nerve cell (also called a neuron) to the impulse-receiving dendrites of the next nerve cell (1)
In vertebrates it consists of two main parts, the central nervous system (CNS) and the peripheral nervous system (PNS). The peripheral system is one of the key parts that make up the nervous system of an animal’s brain. (2) Its main function is to connect the central nervous system to the limbs and organs hence creating a connection between the brain and the spinal cord and the rest of the body. The PNS can further be divided into the somatic system and the visceral nervous system. (2)
The central nervous system is the part of the nervous system consisting of the brain and the spinal cord. It can also be called the brain. The transmission of a nerve impulse along a neuron (Neurons are the structural and functional unit of the nervous system) from one end to the other occurs as a result of electrical changes across the membrane of the neuron (3). The membrane of an unstimulated neuron is polarized—that is, there is a difference in electrical charge between the outside and inside of the membrane. (3)
The nervous system enables people to form words, speak, and communicate, understand and manipulate numbers, compose and appreciate music, recognize and understand geometric shapes, plan ahead, and even to imagine and fantasias. All this happens by help of transmission of impulses. When you are holding a glass and it slips by mistake, signals from the hand are sent to the brain at roughly speed of a few meters per second, then they are sent back, and the hand reacts by grabbing the glass. Nerves send impulses through a process called action potential. Action potential is a rapid change in the membrane of a neuron resulting in the transmission of signals along the length of the neuron. (4) A neuronal action potential has three main stages: depolarization, repolarization, and hyperpolarization. The initial depolarization is determined by the cell’s threshold voltage. (4)
The brain’s functions are both mysterious and remarkable, relying on billions of nerve cells and the internal communication between them. All thoughts, beliefs, memories, behaviors, and moods arise within the brain. The brain is the site of thought and intelligence, and the control center for the entire body. The brain coordinates the abilities to move, touch, smell, taste, hear, and see.
In my next round of research, I will look at how Parkinson’s Disease affects the nervous system and the person with the illness.
