1 results
9 - Hyperhidrosis
-
- By DeeAnna Glaser, Department of Dermatology, Saint Louis University School of Medicine, St Louis, MO, USA, Stephanie Benson, University of Colorado, School of Medicine, Denver
- Edited by Anthony B. Ward, Michael P. Barnes
-
- Book:
- Clinical Uses of Botulinum Toxins
- Published online:
- 02 December 2009
- Print publication:
- 22 March 2007, pp 175-200
-
- Chapter
- Export citation
-
Summary
Introduction
Sweating is a normal physiological response to increasing body temperature and is an important mechanism in releasing heat produced from endogenous and exogenous sources. The heat regulatory center is located in the brain within the hypothalamus, particularly involving the pre-optic and anterior nuclei. These sections of the brain monitor core body temperature through the blood stream, and the body's response to increasing temperature is to release heat through sweat.
Sweating is controlled by the sympathetic nervous system through its preganglionic and postganglionic pathways. Nerve fibers exit the pre-optic or anterior nuclei and descend ipsilaterally through the spinal cord until they reach the intermediolateral column, where they leave the cord and enter the sympathetic chain. The postganglionic fibers leave the chain and join the peripheral nerves until they reach the sweat gland. The neurotransmitter for the sympathetic nervous system is generally norepinephrine; however, the neurotransmitter mainly involved in the sweating process is acetylcholine. Other chemical mediators found in the neuromuscular junction during sweating include vasoactive intestinal peptide, atrial natriuretic peptide, galanin, and calcitonin gene related peptide.
Three glands are important in the creation of sweat: the eccrine, apo-eccrine, and apocrine glands. They are located superiorly in the subcutaneous fat at the junction of the dermis and subcutaneous fat. Between two and four million eccrine glands are found within the skin, and their function is to secrete water while conserving sodium chloride for electrolyte maintenance. The eccrine gland consists of a secretory coil and a duct.