Mammalian cells are the basic building blocks of mammals, including humans. They are eukaryotic cells, meaning they have a defined nucleus and organelles. These cells can be found in various tissues and perform essential functions such as growth, metabolism, and reproduction. Mammalian cells can be classified into different types, such as muscle cells, nerve cells, and blood cells, each specialized for specific roles. They are also used in scientific research and biotechnology, often cultured in laboratories to study diseases or develop new treatments.