The papilla is the productive organ of the hair. Its proper function depends on nourishment and oxygen from the blood stream. Hair grows as a result of mitosis and the multiplication of the soft cells in the papilla. The bulb and root are formed from these cells. These cells also cover the papilla.
Hair cells originate in the portion of the bulb that fits over the top and sides of the papilla. Growth starts at the top of the papilla. This process forms the medulla. the sloping sides of the papilla give birth to the cortex. The cuticle originates where the outer rim of the bulb lies along the base of the papilla. Cells just above the papilla are the youngest. THe cells at the point of the hair shaft are the oldest
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