Which process occurs when applying heat to an injured area?

When heat is applied to an injured area, it causes dilation of blood vessels. This process is important because dilation increases blood flow to the affected area, which can help relieve pain and promote healing. When blood vessels dilate, they allow more blood to reach the area, which provides essential nutrients and oxygen while also helping to clear away waste products. This increased circulation is crucial for the inflammatory response in healing tissues, aiding in the recovery process.

In contrast, constriction of blood vessels would reduce blood flow, which is counterproductive when treating an injury with heat. Similarly, an increase in nerve sensitivity might occur with certain types of stimuli but does not specifically relate to the physiological response of heat application. Lastly, a reduction of blood flow contradicts the healing benefits that heat application aims to achieve by bringing more blood to the area.