Multiple Choice
Which portal of entry is the most commonly used by pathogens in the human body?
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21. The Immune System
Introduction to First-Line Defenses
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Which of the following is not an example of a portal of entry for microorganisms?
A
Gastrointestinal tract
B
Respiratory tract
C
Lymph nodes
D
Skin
Verified step by step guidance1
Understand the concept of 'portal of entry': A portal of entry is a site through which microorganisms enter the host's body. Common portals of entry include mucous membranes, skin, and parenteral routes.
Identify the common portals of entry: The gastrointestinal tract and respiratory tract are both common portals of entry for pathogens. The skin can also serve as a portal of entry, especially when there are cuts or abrasions.
Consider the function of lymph nodes: Lymph nodes are part of the immune system and are involved in filtering lymphatic fluid and trapping pathogens. They are not a site where pathogens typically enter the body.
Compare the options: Gastrointestinal tract, respiratory tract, and skin are all potential entry points for microorganisms. Lymph nodes, however, are not an entry point but rather a part of the body's defense system.
Conclude which option is not a portal of entry: Based on the understanding of the function of lymph nodes, determine that they are not a portal of entry for microorganisms.
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