What is the function of sweat glands?

Sweat glands play a crucial role in regulating body temperature through the process of perspiration. When the body heats up—due to exercise, environmental temperatures, or other factors—sweat glands secrete sweat, which is primarily made up of water and some salts. As sweat evaporates from the surface of the skin, it dissipates heat, thereby cooling the body down. This thermoregulatory function is vital for maintaining homeostasis, especially in warm conditions or during physical exertion.

The other functions listed in the question pertain to different biological processes. While glands in the body do produce hormones, sweat glands are specifically adapted for thermoregulation, not endocrine functions. Vitamin D synthesis occurs primarily in the skin in response to sunlight exposure but is not a role of sweat glands. Lastly, hair follicles are connected to sebaceous glands, which produce oil, but they do not have a relationship with the function of sweat secretion. Thus, the primary and most significant role of sweat glands is indeed the regulation of body temperature through perspiration.