No physician who enters into a practice agreement with a licensed physician assistant in accordance with and within the terms of any permission granted by the commission is considered as aiding and abetting an unlicensed person to practice medicine. The supervising physician and physician assistant shall each retain professional and personal responsibility for any act which constitutes the practice of medicine as defined in RCW
18.71.011 or the practice of osteopathic medicine and surgery as defined in RCW
18.57.001 when performed by the physician assistant.