Anatomy & Morphology

Integumentary System

외피계

Definition

The organ system forming the outer covering of the body, including skin, scales, feathers, hair, and nails.

Detailed Explanation

The integumentary system is the body's first line of defense against pathogens, UV radiation, and dehydration. Its evolutionary diversity is remarkable: fish scales are modified from the same developmental pathway as teeth; bird feathers are highly derived reptile scales; mammalian hair traps insulating air. Skin also plays roles in communication — color-changing cephalopods and flushing primates convey social signals through integument.

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