Final answer:
Macrophages are the cells that extend the inflammatory response and are typically found at chronic bacterial infection sites. They can both phagocytize pathogens and produce chemicals that promote inflammation.
Step-by-step explanation:
The cells that are responsible for extending the inflammatory response and are often found at sites of chronic bacterial infection are macrophages. Macrophages are derived from monocytes that leave the bloodstream and enter tissues. These cells are not only phagocytic, meaning they can engulf and digest pathogens, but they also produce chemicals that promote inflammation, further supporting the immune response during the extension of an infection.
Neutrophils are also important in the acute phase of infection, as the first responders, but they are typically more associated with the initial responses to bacterial infections rather than the chronic phase. Mast cells contribute to inflammation by releasing histamine which helps increase the permeability of capillaries to allow immune cells into the tissue. However, in the context of chronic bacterial infections, it is the macrophages that are particularly key in perpetuating the inflammation and defense against the pathogen.
The cells responsible for extending the inflammatory response and found at chronic bacterial infection sites are macrophages. Macrophages are phagocytic immune cells that engulf and digest pathogens. They also release chemicals to promote inflammation, such as cytokines, which recruit other immune cells to the site of infection. Mast cells, neutrophils, and lymphocytes are not typically involved in the prolonged inflammatory response seen in chronic bacterial infections.