An internal bus system is a communication pathway within a computer that transfers data between different components, such as the CPU, memory, and input/output devices. It allows these components to share information efficiently, ensuring that tasks are completed quickly and accurately. The internal bus consists of multiple lines, including data, address, and control lines. The data bus carries the actual data being transferred, while the address bus specifies the location of the data. The control bus manages the signals that coordinate the operations of the various components, making the internal bus system essential for a computer's functionality.