Sweat is secreted by sweat glands located throughout the body. There are two main types:
1. Eccrine Glands: The Primary Sweat Producers
The majority of sweat production comes from eccrine glands. These glands are distributed widely across the skin's surface, particularly in the transdermal layer, and are crucial for thermoregulation (maintaining body temperature). Eccrine glands secrete a watery fluid, primarily composed of water, electrolytes (like sodium and chloride), and small amounts of urea and other substances. As noted in several sources, such as the Physiology of sweat gland function https://pmc.ncbi.nlm.nih.gov/articles/PMC6773238/, sweating rate is influenced by both the number of active glands and the secretion rate of each gland. The development and function of these glands are discussed extensively in Eccrine sweat gland development and sweat secretion https://pmc.ncbi.nlm.nih.gov/articles/PMC5508982/.
2. Apocrine Glands: Specific Locations & Secretions
Apocrine glands are located in specific areas such as the axilla (armpits), pubic region, and around the nipples. Unlike eccrine glands, their secretions are thicker and contain more organic compounds, contributing to body odor. While these glands also produce sweat, their contribution to overall sweating is less than that of eccrine glands. Research such as Regional variations in transepidermal water loss, eccrine sweat gland density and apocrine gland development in human skin https://extremephysiolmed.biomedcentral.com/articles/10.1186/2046-7648-2-4 highlights regional differences in sweat gland distribution and function. The article Dermcidin: a novel human antibiotic peptide secreted by sweat glands https://www.nature.com/articles/ni732 further underscores the role of sweat in innate immunity.
Stimuli for Sweat Secretion
As outlined in Neural control of sweat secretion: a review https://pubmed.ncbi.nlm.nih.gov/28714085/, acetylcholine released by sympathetic nerves is a powerful stimulator of sweat secretion. Different types of sweat (stress, heat, etc.) are mentioned by Secret Clinical Strength Antiperspirant https://secret.com/en-us/shop/clinical-strength-invisible-solid although the underlying physiological mechanisms remain the same. Cleveland Clinic's overview of exocrine glands also notes the variety of secretions from different exocrine glands, including sweat glands https://my.clevelandclinic.org/health/body/22947-exocrine-glands.
In summary, sweat glands, primarily eccrine and apocrine, secrete sweat. The type and amount of sweat produced depend on several factors, including temperature, stress, and other stimuli.
