The effects of thermal stimulation on the ultrastructure of the fundus and duct of the equine sweat gland.
Abstract: Sweating in the horse had little effect on the ultrastructure of the glandular duct, other than on the lumen which enlarged. The fundus secretory cells, which in the resting gland were packed with vesicles, gradually lost them as sweating progressed until, after 4 hours of activity, few remained. Sweat appeared to be largely the product of secretion (a) by fluid transport, probably involving a region of complex cellular interdigitations adjacent to the basement membrane and (b) by exocytosis of vesicles, although a secondary mechanism of vesicle loss by micro-apocrine secretion may occur. However, the products of cell death also contribute to sweat formation. The myoepithelium appeared contracted throughout. The function of the lower duct body, where complex basal infoldings of the luminal cells penetrated to the basement membrane, may differ from that of the upper portion. Dendritic Langerhans cells were found between the epithelia throughout the duct and fundus.
Publication Date: 1982-08-01 PubMed ID: 7130047PubMed Central: PMC1168125
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- Journal Article
Summary
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This research evaluates how thermal stimulation, or heat, affects the structure and function of sweat glands in horses, highlighting the role of sweat glands in heat regulation, with particular emphasis on fluid transport and exocytosis in the secretion process.
Overview of the Research Study
- The research was conducted on horses with particular focus on their sweat glands. The sweat glands of a horse are mainly divided into two parts: the fundus (the part that produces sweat) and the glandular duct (the tube that carries the sweat to the skin surface).
- The study primarily investigated the ultrastructure (or detailed structure visible only with high-powered microscopes) of these regions of the sweat gland to understand their functional changes when the horse starts to sweat.
Effects of Sweating on the Sweat Gland
- Upon thermal stimulation that causes the horse to sweat, the glandular duct’s lumen (the inside space of a tubular structure) enlarges.
- Simultaneously, the secretory cells of the fundus undergo noticeable changes. At rest, these cells are densely packed with vesicles (small sac-like structures that store and transport substances). However, as the horse sweats, these vesicles gradually deplete. After about 4 hours of sweating, only a few remain.
Secretion Process and Fluid Transport
- Sweat is considered to be predominately the product of two primary mechanisms: fluid transport and exocytosis of vesicles.
- Fluid transport likely involves a complex network of cellular structures close to the basement membrane (a thin layer of cells at the bottom forming the base of the tissue).
- In addition to these primary mechanisms, the study suggests the occurrence of a possible secondary mechanism, known as micro-apocrine secretion, which could contribute to the loss of vesicles.
Additional Observations
- The study also suggests that products resulting from cell death may contribute to the formation of sweat.
- Throughout the whole process, a structure called the myoepithelium (a type of muscle layer found in some glands) appears to remain contracted.
- There is a change in function in the lower part of the duct, indicated by complex inward folds of the luminal cells penetrating the basement membrane.
- The presence of dendritic Langerhans cells (a type of immune cell) was observed throughout the duct and fundus (gland’s body).
Implications
- Findings from this study shed light on how horse sweat glands respond to heat and help to better understand the mechanism behind sweat production and secretion in horses.
- These insights could be vital in developing strategies to manage horses in hot environments, potentially improving their comfort and performance.
Cite This Article
APA
Montgomery I, Jenkinson DM, Elder HY.
(1982).
The effects of thermal stimulation on the ultrastructure of the fundus and duct of the equine sweat gland.
J Anat, 135(Pt 1), 13-28.
Publication
Researcher Affiliations
MeSH Terms
- Animals
- Female
- Horses / anatomy & histology
- Hot Temperature
- Male
- Microscopy, Electron
- Sweat Glands / metabolism
- Sweat Glands / ultrastructure
- Sweating
- Vacuoles / ultrastructure
References
This article includes 19 references
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Citations
This article has been cited 1 times.- McDonald RE, Fleming RI, Beeley JG, Bovell DL, Lu JR, Zhao X, Cooper A, Kennedy MW. Latherin: a surfactant protein of horse sweat and saliva. PLoS One 2009 May 29;4(5):e5726.
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