What is the anatomy of tuberculosis?

Answer 1

Tuberculosis is caused by mycobacterium tuberculosis.

It is an acid-fast bacilli which means that it is rod-shaped and acid-fast because it retains the fuschin (pink) dye even after acid-alcohol decoloration. Histologically it will appear blue because as said it retains the fuschin stain and not the counterstain methylene blue.

The pathophysiology is due to the chronic activation of T helper and macrophages.

1. Inhalation of the MTB into the alveoli

2. Alveolar macrophage phagocytosis but NOT activated because the phagosome does not fuse with the lysosome (-> no phagolysosome formed!) This means that the MTB can continue to replicate intracellularly

3. DTH is initiated (Th1 recognize MHC of alveolar macrophage -> Th1 activation -> Release IFN-gamma -> Activate macrophage to kill it intracellularly) -> PPD test becomes positive

4. But still many inactivated - continue to replicate and the chronic activation of macrophage and Th1. Specifically, the macrophage differntiates to become epitheloid cells which walls off the pathogen

5. Now there is necrosis within the granuloma

6. When immunity is low, the tubercle liquifies and this releases MTB and its antigens, resulting to miliary TB

Answer 2

Mycobacterium is rod-shaped

Answer 3

It is just round, man.

Answer 4

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