Chronic bronchitis can be caused by flu viruses, bacterial infections, inhaling dust, etc. These things can irritate your airway and make them swell up. This is why we usually feel congested and short of breath when we have bronchitis (lots of coughing too).
Stroke can be caused by a rupture or clot in a blood vessel in the brain. Blood vessels carry oxygen and other vital nutrients. So when the vessel is damaged, parts of the brain might not be receiving oxygen and nutrients. This can cause brain tissue to start dying.
