Final answer:
The 5th stage of the host response to TB is the rupture of the caseous granuloma. Tubercles formed in the lungs become walled off, creating a caseous center where the bacteria can grow. The rupture of the tubercles facilitates transmission of the bacteria.
Step-by-step explanation:
The 5th stage of the host response to TB is the rupture of the caseous granuloma. When the tubercles formed in the lungs become walled off, a caseous center is created where the M. tuberculosis bacteria can grow and multiply. Over time, these tubercles may rupture, releasing the bacteria into the pulmonary capillaries and spreading them through the bloodstream to other organs, causing miliary tuberculosis. The rupture of the tubercles also facilitates the transmission of the bacteria to other individuals through coughs.