physiological barriers

Physiological barriers are natural body defenses that prevent harmful substances, like pathogens or toxins, from entering or causing damage. Examples include the skin, which acts as a tough outer layer stopping microbes from entering the body; mucus membranes, which trap and remove invaders; and stomach acids that kill bacteria swallowed with food. These barriers work together to maintain health by stopping potential threats before they reach sensitive areas, forming an essential part of the immune defense system.