- The Central Nervous System (CNS) includes the brain and spinal cord.
- The Peripheral Nervous System (PNS) connects the CNS to other parts of the body, and is composed of nerves(bundles of neurons)
The Neuron
Nervous tissue is composed of two main cell types: neurons and glial cells.
Neurons transmit nerve messages. Glial cells are in direct contact with neurons and often surround them.
The neuron is the functional unit of the nervous system.
Humans have about 100 billion neurons in their brain alone.
Functions of the three parts of a neuron:
- Axon: It conducts messages away from the cell body.
- Dendrite: It receives information from axon of another cell and conducts the messages towards the cell body.
- Cell body: It contains nucleus, mitochondria, and other organelles. It is mainly concerned with the maintenance and growth.
Synapses
- The junction between a nerve cell and another cell is called a Synapse.
- The space between two cells is known as the synaptic cleft.
- The function between two neurons is called a ‘ganglion’.
