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 different tasks. For example, red blood cells carry oxygen, while white blood cells are part of the immune system, helping to fight infections. Together, these cells work in harmony to maintain the body's overall health and function.