The human body is made up of trillions of cells. Cells of the nervous system, called nerve cells or neurons, are specialized to carry “messages” through an electrochemical process. The human brain has approximately 100 billion neurons. To learn how they carry messages, read about the action potential.
It is an electrically excitable cell that processes and transmits information through electrical and chemical signals. These signals between them occur via synapses, specialized connections with other cells. They can connect to each other to form neural networks. They are the core components of the brain and spinal cord of the central nervous system (CNS), and of the ganglia of the peripheral nervous system.
Anatomy of Neurons
Neurons is made up of several parts:
- Cell Body
Neurons vs Other Cells
Neurons are similar to other cells in the body because:
- They are surrounded by a cell membrane.
- They have a nucleus that contains genes.
- They contain cytoplasm, mitochondria and other organelles.
- They carry out basic cellular processes such as protein synthesis and energy production.
Neurons differ from other cells in the body because:
- They have specialize cell parts called dendrites and axons. Dendrites bring electrical signals to the cell body and axons take information away from the cell body.
- They communicate with each other through an electrochemical process.
- They contain some specialized structures (for example, synapses) and chemicals (for example, neurotransmitters).
Neurons in Brain
The number of neurons in the brain varies dramatically from species to species. One estimate (published in 1988) puts the human brain at about 100 billion (1011) neurons and 100 trillion (1014) synapses. A lower estimate (published in 2009) is 86 billion, of which 16.3 billion are in the cerebral cortex, and 69 billion in the cerebellum.By contrast, the nematode worm Caenorhabditis elegans has just 302 neurons, making it an ideal experimental subject as scientists have been able to map all of the organism’s neurons. Many of its properties, from the type of neurotransmitters used to ion channel composition, are maintained across species, allowing scientists to study processes occurring in more complex organisms in much simpler experimental systems.