What are the four cardinal signs of inflammation?

The four cardinal signs of inflammation are swelling, heat, redness, and pain. These signs are essential indicators of the inflammatory response, which occurs when tissue is damaged or infected.

Redness, also known as erythema, occurs due to increased blood flow to the affected area, resulting from the dilation of blood vessels. Heat is another cardinal sign that accompanies redness and is caused by the increased blood flow as well; the inflamed area becomes warmer than surrounding tissues. Pain arises from the release of chemical mediators that sensitize nerve endings, signaling the body that there is injury or infection that needs attention.

Swelling is the result of increased permeability of blood vessels allowing fluid, proteins, and immune cells to escape into the tissues, contributing to the inflammatory process. Together, these four signs of inflammation provide a comprehensive picture of the body's response to injury or infection and serve to mobilize immune cells to the site of damage, promoting healing and defense against pathogens.

Other options listed may contain misleading or incorrect information about inflammation signs, such as fever or tachycardia, which can accompany inflammation but are not classified as the cardinal signs.