Electrolysis Practice Exam

The bulb of the hair surrounds which of the following structures?

1. Hair shaft

2. Dermal papilla

3. Hair follicle

4. Arrector pili muscle

The correct answer is: Dermal papilla

The bulb of the hair is the enlarged base of the hair follicle located beneath the skin's surface. It is specifically associated with the dermal papilla, which plays a vital role in hair growth and health. The dermal papilla is a small, capillary-rich structure that supplies nutrients and signals to the hair follicle, stimulating growth and ensuring that the hair remains healthy. While the hair shaft is the part of the hair that emerges from the skin, it does not surround the bulb itself. The hair follicle is the overall structure that includes the bulb and the papilla among other components, but it is broader than just the bulb. The arrector pili muscle is a tiny muscle attached to the follicle that causes hair to stand up when you are cold or frightened, but it does not encase or directly surround the bulb. Thus, the correct association of the bulb of the hair is with the dermal papilla, as this relationship is crucial for understanding hair biology and growth.