Answer:
The oxygen enters the bloodstream from the alveoli, which are tiny sacs in the lungs where gas exchange takes place. The transfer of oxygen into the blood is through simple diffusion. While oxygen moves from the capillaries and into body cells, carbon dioxide moves from the cells into the capillaries and starts with high concentration but fades to low concentration.
Explanation:
When the body is exposed to allergens or irritants, it will trigger the immune systems through different mechanism. However, the common pathway would result to multi-cellular inflammation, enhanced bronchial responsiveness, airflow obstruction and activation of immunological cell infiltration. Here, the inflammatory cell infiltrate are composed of varying amounts of eosinophils, neutrophils, and lymphocytes.
Moreover, T cells in the lung appear to orchestrate an immune response with a strong T helper type 2 (Th2) component when allergens drive the process.
