Which system is primarily responsible for the protection and regulation of body temperature?

The integumentary system is primarily responsible for the protection and regulation of body temperature. This system includes the skin, hair, nails, and associated glands. The skin acts as a barrier against environmental hazards, while also playing a crucial role in thermoregulation. Through processes such as sweating and vasodilation (widening of blood vessels), the integumentary system helps dissipate heat when the body temperature rises. Conversely, when the body is cold, vasoconstriction (narrowing of blood vessels) occurs to retain heat.

Additionally, sweat glands and blood vessels in the skin can adjust their activity based on temperature changes, further assisting in maintaining homeostasis. Other systems, while connected to temperature regulation, do not directly control it as the integumentary system does. The muscular system contributes to heat production through muscle activity, the nervous system helps signal these processes, and the endocrine system releases hormones that can affect metabolism and heat production, but the primary means of protection and temperature regulation lies with the integumentary system.