what is one major function of arrector pili muscle contraction
Arrector pili muscle Contraction of the muscles has a number of different purposes. Its principal function in the majority of mammals is to provide insulation: air becomes trapped between the erect hairs, helping the animal retain heat. Erection of the porcupine's long, thick hairs causes the animal to become more intimidating, scaring predators. Pressure exerted by the muscle may cause sebum to be forced along the hair follicle towards the surface, protecting the hair.
Muscle contraction Length-tension relationship relates the strength of an isometric contraction to the length of the muscle at which the contraction occurs. Muscles operate with greatest active tension when close to an ideal length (often their resting length). When stretched or shortened beyond this (whether due to the action of the muscle itself or by an outside force), the maximum active tension generated decreases.[28] This decrease is minimal for small deviations, but the tension drops off rapidly as the length deviates further from the ideal. Due to the presence of elastic proteins within a muscle cell (such as titin) and extracellular matrix, as the muscle is stretched beyond a given length, there is an entirely passive tension, which opposes lengthening. Combined together, there is a strong resistance to lengthening an active muscle far beyond the peak of active tension.