An irregularly shaped thickening at the end of the developing process of the nerve cell, which makes its way through the surrounding tissue. It consists of a flattened part of the process of a nerve cell with many thin spines. Microspines have a thickness of 0.1 to 0.2 μm and can reach 50 μm in length, the wide and flat area of the growth cone is about 5 μm wide and long, although its shape can vary. The spaces between the microspines of the growth cone are covered with a folded membrane. Microspines are in constant motion – some are retracted into the growth cone, others lengthen, deviate in different directions, touch the substrate and can stick to it. The growth cone is filled with small, sometimes connected to each other, membrane vesicles of irregular shape. Directly under the folded areas of the membrane and in the spines there is a dense mass of entangled actin filaments. The growth cone also contains mitochondria, microtubules, and neurofilaments present in the body of the neuron. It is likely that microtubules and neurofilaments are elongated mainly by the addition of newly synthesized subunits at the base of the neuronal process. They move at a speed of about a millimeter per day, which corresponds to the speed of slow axon transport in a mature neuron.