myoepithelialen

Myoepithelial cells are a type of epithelial cell found in various organs, including the mammary glands, salivary glands, sweat glands, and lacrimal glands. They are characterized by their contractile properties, which allow them to regulate the secretion and flow of fluids from these glands. Myoepithelial cells are derived from the ectoderm during embryonic development and are distinct from other epithelial cells due to their ability to contract and relax in response to various stimuli.

In the mammary glands, myoepithelial cells surround the mammary alveoli and ducts, forming a layer between the epithelial cells and the basement membrane. They play a crucial role in milk ejection during lactation by contracting in response to hormonal signals, such as oxytocin. This contraction helps to expel milk from the alveoli and ducts into the lactiferous ducts, which then transport the milk to the nipple.

Myoepithelial cells are also found in salivary glands, where they help to regulate the flow of saliva. In sweat glands, myoepithelial cells contribute to the regulation of sweat secretion. In the lacrimal glands, myoepithelial cells help to control the flow of tears.

The contractile properties of myoepithelial cells are mediated by the presence of smooth muscle-like actin and myosin filaments, which allow them to generate force and regulate fluid flow. This unique combination of epithelial and contractile properties makes myoepithelial cells essential for the proper functioning of various exocrine glands.