What Is the Body's First Line of Defense Against Infection

question 21

Multiple Choice

What is the body's first line of defense against infection?

• A)Skin and mucous membranes
• B)Fever
• C)Leukocytes
• D)None of the above

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Definitions:

Interstitial Fluid

Fluid that surrounds the body’s cells; consists of dissolved substances that leave the blood capillaries by filtration and diffusion.

Metabolism

The set of life-sustaining chemical reactions in organisms to convert food into energy, and build or maintain their cells.

First Messenger

Chemical signal, such as a peptide hormone, that binds to a plasma membrane receptor protein and alters the metabolism of a cell because a second messenger is activated.

Second Messenger

Chemical signal, such as cyclic AMP, that causes the cell to respond to the first messenger—a hormone bound to a plasma membrane receptor protein.