Growth cone

Growth Cone

The Growth Cone is a dynamic, actin-supported extension of a developing or regenerating neurite seeking its synaptic target. Its existence was originally proposed by Spanish histologist, Santiago Ramón y Cajal, based on static images he observed under the microscope. He compared the growth cone shape to an "axoplasmic fountain" or a "spray of protoplasmic drops" and proposed that it was responsible for the growth of the axon.

Structure

The growth cone has a flat, sheet-like body called the lamellipodium which contains protrusions called filopodia. The lamellipodium is the main body of the growth cone and contains a dense network of actin filaments. The filopodia, which are long, finger-like extensions that come out of the growth cone, also contain actin filaments. The actin filaments in both the lamellipodium and filopodia are constantly being assembled and disassembled, which allows the growth cone to move.

Function

The growth cone plays a critical role in the development of the nervous system by guiding the axon to its target location. It does this by sensing and responding to molecular cues in its environment. These cues can be either attractive or repulsive, and they guide the growth cone by binding to receptors on its surface and triggering intracellular signaling pathways that regulate the assembly and disassembly of the actin cytoskeleton.

Clinical Significance

Understanding the mechanisms of growth cone guidance is important for developing therapies for neurological disorders and injuries. For example, after a spinal cord injury, the growth cones of damaged neurons often fail to regenerate and reconnect with their targets. By understanding how growth cones navigate, scientists may be able to develop treatments that promote regeneration and recovery after spinal cord injury.

See Also

• Neuron
• Axon
• Actin
• Spinal cord injury

References

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