What structure contains capillaries that nourish the hair follicle?

The answer is the papilla, which is a small, cone-shaped structure located at the base of the hair follicle. It is composed of connective tissue and contains a network of capillaries that play a vital role in nourishing the hair follicle. These capillaries supply essential nutrients and oxygen to the growing hair, which is critical for healthy hair development. As the hair grows, the cells from the papilla help to support the hair's production by providing the necessary resources.

The follicular bulb contains the hair root and is where the cells multiply and keratinize to form hair, but it does not contain capillaries itself. The dermal sheath surrounds the hair follicle and provides some structural support but, similarly, does not have direct vascular supply for nourishment. The hair shaft is the part of the hair that is visible above the skin's surface and is comprised of dead keratinized cells, which means it does not require nourishment from the capillaries. Understanding the role of the papilla is crucial in grasping how hair growth is supported at a cellular level.