What is NOT a function of the hair bulb?

The hair bulb is a critical component of the hair follicle, responsible for several important functions related to hair growth and health. Among its primary roles are providing nutrients to the hair through dermal papillae, which supply blood flow and nourishment essential for hair development. Additionally, the hair bulb plays a significant role in anchoring the hair follicle within the dermis, ensuring that the hair remains securely in place as it grows.

The initiation of hair growth is another key function of the hair bulb, as it is where the hair matrix is located. This matrix produces new hair cells, which push older cells upward, leading to hair elongation. The processes of nourishment, anchoring, and hair growth initiation are well-documented roles of the hair bulb.

In contrast, while hair itself can respond to environmental stimuli (such as movement or changes in temperature), the hair bulb does not function as a sensory receptor. Therefore, the detection of environmental changes is not a function performed by the hair bulb. This discernment highlights why "detects environmental changes" stands out as the correct answer, as this function is associated more with the skin's sensory receptors rather than the hair bulb itself.