explain what neurons are
A neuron is a nerve cell. The brain is made up of approximately 100 billion neurons. Neurons are similar to other cells in the body in some ways such as: 1  Neurons are surrounded by a membrane.2  Neurons have a nucleus that contains genes.3  Neurons contain cytoplasm, mitochondria and other organelles.he brain is made up of approximately 100 billion neurons. Neurons are similar to other cells in the body in some ways such as: 1  Neurons are surrounded by a membrane. 2  Neurons have a nucleus that contains genes.