What are desmosomes, and what is their function?

Desmosomes are a type of cell junction found in animal cells that act like 'spot welds' or rivets, fastening cells together into strong sheets. They consist of protein plaques on the cytoplasmic side of the plasma membrane, with intermediate filaments extending into the cytoplasm and cadherin proteins extending into the extracellular space to link adjacent cells. Their primary function is to provide strong adhesion and mechanical stability to tissues that experience significant mechanical stress, such as skin and heart muscle.