IMMUNOLOGY

Detailed explanation-1: -Specific immune system cells release substances into the immediate area that make the blood vessels wider and more permeable. This causes the area around the infection to swell, heat up and redden, and inflammation results. A fever may develop as well.

Detailed explanation-2: -(b) Histamine increases blood flow to the wound site, and increased vascular permeability allows fluid, proteins, phagocytes, and other immune cells to enter infected tissue. These events result in the swelling and reddening of the injured site, and the increased blood flow to the injured site causes it to feel warm.

Detailed explanation-3: -At the tissue level, inflammation is characterized by redness, swelling, heat, pain, and loss of tissue function, which result from local immune, vascular and inflammatory cell responses to infection or injury [5].

Detailed explanation-4: -When inflammation happens, chemicals from your body’s white blood cells enter your blood or tissues to protect your body from invaders. This raises the blood flow to the area of injury or infection. It can cause redness and warmth. Some of the chemicals cause fluid to leak into your tissues, resulting in swelling.

Detailed explanation-5: -When a pathogen invades a tissue, it almost always elicits an inflammatory response. This response is characterized by pain, redness, heat, and swelling at the site of infection, all caused by changes in local blood vessels.

Detailed explanation-6: -Your immune system sends out its first responders: inflammatory cells and cytokines (substances that stimulate more inflammatory cells). These cells begin an inflammatory response to trap bacteria and other offending agents or start healing injured tissue. The result can be pain, swelling, bruising or redness.