Enteroendocrine cells of the intestine are the most numerous endocrine cells of the body. In a sense they are known to act as chemoreceptors, initiating digestive actions and detecting harmful substances and initiating protective responses.
The typical manufacturer's warranty on a solar panel is 25 to 30 years, but panels can last up to 40 years with care and attention.
Some panels have been known to still be more than 80% efficient by the end of their life. With care and attention, solar panels could potentially last over forty years after installation, although their performance will have deteriorated marginally over that time. The 40-50 year life expectancy goes for both monocrystalline and polycrystalline solar panels. Less is known about the lifespan of thin film panels at the moment but, as they also have 25 year warranties as standard, they are expected to match the long life of crystalline panels.