Surface Barriers,such as Cutaneous and Mucous Membranes,serve the Immune System

question 21

Multiple Choice

Surface barriers,such as cutaneous and mucous membranes,serve the immune system as the:

• A)first line of defense.
• B)second line of defense.
• C)third line of defense.
• D)fourth line of defense.

---

Definitions:

Tinnitus

The hearing of sound when no external sound is present, often described as ringing in the ears, but may also sound like clicking, hissing, or roaring.

Objective Tinnitus

A rare form of tinnitus that can be heard by others, typically caused by vascular anomalies or involuntary muscle contractions near the ear.

Intermittent

Occurring at irregular intervals; not continuous or steady.

Auditory Frequency

Auditory frequency refers to the number of sound vibrations or cycles per second, perceived as the pitch of a sound, measured in hertz (Hz).