The term "arrectores pilorum" refers to the small muscles that cause goosebumps. It is pronounced as /əˈrɛktərɪz paɪˈlɔrəm/. The IPA transcription helps explain the spelling of the word by breaking it down into its individual sounds. The "a" in "arrectores" is pronounced as "uh", while the stress falls on the second syllable. In "pilorum", the "i" is pronounced as "eye" and the stress is on the first syllable. The use of IPA phonetic transcription helps accurately convey how the word is pronounced.
The term "arrectores pilorum" refers to small muscles that are responsible for causing the hairs on the skin to stand up or become erect. It is derived from Latin, where "arrectores" means "to raise" or "to erect," and "pilorum" refers to "hair."
These tiny involuntary muscles are attached to the hair follicles in mammals, including humans. When they contract, they cause the hair to stand straight up, resulting in a condition commonly known as "goosebumps" or "horripilation." This phenomenon occurs as a response to various stimuli such as cold temperature, fear, anger, or excitement.
The arrectores pilorum muscles are controlled by the sympathetic nervous system, which is responsible for regulating the body's involuntary responses. When the sympathetic nervous system is activated, it stimulates the contraction of these muscles. This activation occurs through the release of neurotransmitters like norepinephrine, which binds to receptors on the muscle cells, triggering the contraction.
While the arrectores pilorum muscles were once more significant in our evolutionary history, serving to help insulate and protect our ancestors' fur-covered bodies in response to external threats, their role in humans today is more limited. Despite their diminished significance, the phenomenon of hairs standing on end due to muscle contraction remains an intriguing physiological response in humans and other mammals.
Unstriped muscular fibers in the skin inserted into the bases of the hair-follicles, contraction of which, under the stimulus of cold or of fright, causes the hairs to stand erect, at the same time pulling them outward so as to raise the skin at their base into papillae; the condition so produced is called goose flesh or cutis anserina.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.
The term arrectores pilorum has Latin origins. Arrectores comes from the Latin word arrectus, which means raised or erected. Pilorum is derived from pilus, meaning hair.
Together, arrectores pilorum translates to the muscles that raise the hair. It refers to tiny muscles known as piloerector muscles, which are attached to hair follicles in mammals. When these muscles contract, it causes the hair to stand erect, resulting in the phenomenon commonly referred to as goosebumps or horripilation.