Respiratory System & Its Key Partners: Cardiovascular & Musculoskeletal Systems

1. Cardiovascular system: The respiratory system works closely with the cardiovascular system to supply oxygen to the body's tissues and remove carbon dioxide. The heart pumps oxygenated blood from the lungs to the rest of the body, while the respiratory system brings in oxygen and removes carbon dioxide from the blood.

2. Musculoskeletal system: The respiratory system also works with the musculoskeletal system to facilitate breathing. The muscles of the chest and diaphragm contract and relax to move air in and out of the lungs.