ScienceVerseLearning path: Neurons
The concepts to learn before Neurons, in order. Each step links to its page and, where one exists, its quiz.
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Your path
- CellDirect prerequisite
The basic structural and functional unit of all known living organisms. Every living thing is made of one or more cells, each bounded by a membrane and containing the machinery needed to grow, respond to its environment, and reproduce. Cells fall into two broad types: prokaryotic cells (such as bacteria), which lack a nucleus, and eukaryotic cells (such as those in plants, animals and fungi), which organise their DNA inside a membrane-bound nucleus.
- NeuronsYour goal
Neurons are nerve cells specialised to carry signals. A neuron receives input on its dendrites, adds it up at the axon hillock and, if the input reaches threshold, fires an all-or-nothing electrical impulse — an action potential — along its axon. At most synapses the signal crosses to the next cell as a chemical neurotransmitter. The adult human brain holds about 86 billion neurons and a similar number of non-neuronal cells.