PyArrow, an open-source Python package, is an integral component that bridges the Python ecosystem with Apache Arrow. This package opens up a fast data interchange capability, beneficial for memory-intensive tasks. With PyArrow, data scientists and engineers can effectively handle pandas dataframes or NumPy arrays, along with integration to vast data systems like Hadoop and Parquet. Its serialization abilities and efficient streaming with no copying make it a great tool for constructing scalable data processing systems.