Neural Tissue: Neurons, Glial Cells and Their Functions
Your brain can think, remember and control the body because of neural tissue (nervous tissue). It forms the brain, spinal cord and nerves, acting like the body's control and communication network.
Neural tissue matters because it receives information from sense organs, processes it quickly and sends commands to muscles and glands. Without it, we could not feel, learn or respond.
Key Concepts
The main cell is the neuron, specialised to carry electrical signals called nerve impulses. A neuron has a cell body (cyton) with nucleus, dendrites that receive signals, and a long axon that carries signals away. Many axons are covered by a fatty myelin sheath that speeds conduction and is made by Schwann cells or oligodendrocytes. Glial cells (neuroglia) support, nourish, protect and insulate neurons; they do not carry impulses like neurons. A synapse is the junction where signal passes from one neuron to the next using chemicals called neurotransmitters.
How It Works
- Dendrites receive stimulus from receptors or another neuron.
- Signal travels through cell body to axon as an electrical impulse.
- Myelin sheath allows faster, jumping conduction between nodes of Ranvier.
- At axon ending, neurotransmitter is released into synapse.
- Next neuron or muscle receives it and responds. Glial cells maintain ion balance, remove waste and protect neurons throughout.
Worked Example
Imagine you touch a hot plate. Receptors in skin fire impulses. If the distance to spinal cord is about 0.8 metre and conduction speed in myelinated fibre is about 80 metres per second, time = distance / speed = 0.8 / 80 = 0.01 second. The spinal cord quickly sends command back to arm muscles, and you withdraw your hand in a reflex. This calculation shows why myelin makes responses so fast.
Common Misconceptions
- Glial cells carry nerve impulses. Glial cells support and protect; neurons carry impulses.
- Neurons keep dividing like skin cells. Most neurons do not divide after birth, so brain injury heals poorly.
- Signal jumps across synapse as electricity only. At most synapses, chemicals (neurotransmitters) carry the message across the gap.
Real-World Applications
Understanding neural tissue helps treat paralysis, epilepsy, Parkinson's and Alzheimer's diseases. Anaesthesia blocks nerve impulses. Brain-computer interfaces use neuron signals to control devices. Reflex testing by doctors checks neural pathways.
Neural tissue is the body's fast messaging system. Neurons transmit signals, while glial cells keep the network healthy and efficient.