What substance primarily composes sweat secreted by eccrine glands?

Sweat secreted by eccrine glands is primarily composed of water, sodium chloride (NaCl), and small amounts of other substances like vitamin C. The primary role of eccrine glands is to regulate body temperature through perspiration, which is primarily water. Sodium chloride is included as it helps with the maintenance of electrolyte balance in the body. Vitamin C, although present in smaller quantities, plays a role in skin health and protection against ultraviolet light.

Eccrine glands, found all over the body, are particularly important for thermoregulation. When the body overheats, these glands produce sweat that evaporates off the skin surface, allowing the body to cool down. The specific composition of sweat from these glands reflects their physiological function in temperature regulation and ion balance.