0Final answer:
Sputum is a substance coughed up from the respiratory tract that can indicate a bacterial infection. Bacterial infections can cause inflammation, dilation, and thickening of mucus in the respiratory tract.
Step-by-step explanation:
Sputum is a substance that is coughed up from the respiratory tract and can be examined to determine the presence of microorganisms or other abnormalities. It is often produced in response to a bacterial infection, such as in the case of bronchitis. Bacterial infections can cause inflammation in the respiratory tract, leading to symptoms like coughing and thickening of mucus. Dilation refers to the widening of blood vessels, which can occur as a result of an immune response to infection. Thickening of mucus can also occur as a protective response to help trap and remove pathogens from the respiratory system.