Human Body's Defense Mechanisms Quiz

Chemical Barriers to Infection

• Chemical barriers include substances that inhibit microbial growth or kill pathogens.
• Lysozyme is an example, found in various bodily secretions such as tears and saliva, which breaks down bacterial cell walls.

Lysozyme Function

• Lysozyme's primary function is to enzymatically target and destroy bacteria, aiding in the immune response.
• It contributes to the creation of a hostile environment for pathogens at mucosal surfaces.

Role of Mucous Membranes

• Mucous membranes trap pathogens and particulates, preventing their entry into the body.
• They secrete mucus, which contains antimicrobial substances that help neutralize infections.

Intact Skin as a Barrier

• Intact skin forms a strong mechanical barrier that protects against pathogen penetration and infection.
• It provides the first line of defense by physically blocking entry points.

Lactoferrin Presence

• Lactoferrin is an iron-binding protein present in tears and saliva, which deprives bacteria of iron necessary for their growth.
• This function enhances the body’s ability to combat infections by limiting microbial replication.

Peristaltic Movement

• Peristaltic movement refers to the coordinated contractions of intestinal muscles, aiding in the movement of food.
• It is not a chemical barrier; instead, it mechanically helps eliminate pathogens from the gastrointestinal tract.

Test your knowledge on the structural, mechanical, and chemical barriers that the human body employs to defend against pathogens and foreign invaders.