Circulatory changes that occur in inflammation include Select one: a. decreased blood flow to the area. b. decreased vascular permeability. c. increased viscosity of the blood. d. increased vascular permeability. e. vasoconstriction.
The correct answer and explanation is:
Correct answer: d. increased vascular permeability
During inflammation, several circulatory changes occur as part of the body’s defense mechanism to respond to injury, infection, or harmful stimuli. One of the key features of the inflammatory response is increased vascular permeability.
When tissues are injured or infected, chemical mediators like histamine, bradykinin, and prostaglandins are released from cells such as mast cells, basophils, and damaged tissue cells. These mediators cause the endothelial cells that line blood vessels to contract and separate slightly. This change leads to increased permeability of the blood vessel walls, allowing plasma proteins and white blood cells to leave the bloodstream and enter the tissue spaces. The movement of these components helps fight infection and facilitate healing.
This increased permeability allows essential immune components such as antibodies, complement proteins, and neutrophils to reach the site of injury or infection. The fluid that leaks out of the capillaries also contributes to the swelling or edema commonly observed in inflamed tissues.
Other circulatory changes occur as well, but they support rather than oppose this response. For instance, vasodilation occurs rather than vasoconstriction. Vasodilation increases blood flow to the area, which is why the affected area becomes red and warm. Blood viscosity may change slightly due to fluid loss, but the main driver of the inflammatory process remains the increased permeability and blood flow.
In summary, increased vascular permeability is a hallmark of inflammation. It ensures that immune cells and proteins can leave the blood vessels and reach the tissues where they are needed most, promoting an effective immune response and eventual tissue repair.