Human cells are the basic building blocks of the body. Each cell has a specific function, such as muscle cells that help with movement and nerve cells that transmit signals. Cells contain various components, including the nucleus, which houses genetic material, and mitochondria, which produce energy. There are over 200 different types of human cells, each specialized for particular tasks. For example, red blood cells carry oxygen, while white blood cells are essential for the immune system. Together, these cells work in harmony to maintain the body's overall health and function.