What is the name of the appendage to the hair follicle that causes goosebumps?

The appendage to the hair follicle that causes goosebumps is called the arrector pili. This small muscle is attached to the base of the hair follicle and is responsible for the involuntary action of contracting when the body experiences certain stimuli, such as cold temperatures or strong emotions. When the arrector pili muscles contract, they pull the hair upright, leading to the formation of goosebumps on the surface of the skin.

This natural response can serve various purposes, including insulation by trapping air against the skin when cold or making an animal appear larger in response to fear. Understanding the function of the arrector pili helps in grasping how our body reacts to environmental changes and emotional states. Other terms, like stratum corneum, vellus pili, and cuticle, refer to different parts or types of hair and skin structures, but they do not play a role in generating goosebumps.