Every neuron is made of a cell body (also called a soma), dendrites and an axon. Dendrites and axons are nerve fibres. There are about 100 billion neurons in the human brain, which comprises roughly 10% of all brain cells. The neurons are supported by glial cells and astrocytes.
Neurons are connected to one another and tissues. They do not touch and instead form synapses. These gaps can be chemical synapses or electrical synapses and pass the signal from one neuron to the next.
Types of neurons[change | edit source]
By connection[change | edit source]
There are three classes of neurons: afferent neurons, efferent neurons, and interneurons.
- Afferent neurons carry information from tissues and organs into the central nervous system.
- Efferent neurons transport signals from the central nervous system to the effector cells.
- Interneurons connect neurons within the central nervous system.
By function[change | edit source]
Sensory neurons carry signals from sense organs to the spinal cord and brain.
Relay neurons carry messages from one part of the CNS.
Motor neurons carry signals from the CNS to muscles, motor neurons are connected to the relay neurons. The signal passes between the neurons via synapses. Synapses are microscopic voids between cells where chemicals are released from the axon terminal of one cell to specialized chemical receptors on the dendrite of the receiving cell.
References[change | edit source]
Other websites[change | edit source]
- Fibrinogen found to inhibit EGFR in neuronal cells Blood clotting protein may inhibit spinal cord regeneration
- Cell Centered Database UC San Diego images of neurons.
- High Resolution Neuroanatomical Images of Primate and Non-Primate Brains.