What biological system does tuberculosis affect?

Lungs mostly but...: Tuberculosis spreads by inhalation of droplets containing mycobacterium tuberculosis that were coughed out by an infected person. It enters the lungs, starts to multiply there, travels to regional lymph nodes & can also later spread to any organ system in the body. The initial infection (called primary focus) is almost always in lungs, but reactivation disease can involve any organ.

Extrapulmonary TB: Besides causing infection in the lungs, TB can also cause infection in the spine (potts), central nervous system (meningitis), urinary tract, liver, skin, joints, heart, GI tract and abdomen.