| Growth Cone |
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| developmental neuroscience | |
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A growth cone is a dynamic, Actin -supported extension of a developing Axon seeking its Synaptic target. Their existence was originally proposed by Spanish Histologist Santiago Ramón Y Cajal based upon stationary images he observed under the Microscope . STRUCTURE The morphology of the growth cone can be easily described by using the hand as an analogy. The fine extensions of the growth cone are known as "filopodia". The filopodia are like the "fingers" of the growth cone; they contain actin filaments that give them shape and support. In between filopodia--much like the webbing of the hands--are the "lamellipodia". The filopodia contain Receptors that are important for Axon Guidance . MOVEMENT The growth cones are continually being built up through construction of the actin microfilaments and extension of the Plasma Membrane via Vesicle fusion. Laminin s of the Basal Membrane interact with the Integrin s of the growth cone to promote the forward movement of the growth cone. AXON GUIDANCE Growth cone receptors detect the presence of chemical gradients of axon guidance molecules such as Ephrin s and Semaphorin s. These gradients will either attract or repel the growth cone, thus helping to guide the axon away from certain paths and attracting them to their proper target destinations. This mechanism is what underlies the initial wiring of the nervous system. REFERENCE
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