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Medicine LibreTexts

5: The Skin

The skin is the first of the eleven body systems to be described. Each chapter from now on will cover one body system. The skin, sometimes known as the Integumentary System is, in fact, the largest organ of the body. It has a complex structure, being composed of many different tissues. It performs many functions that are important in maintaining homeostasis in the body. Probably the most important of these functions is the control of body temperature. The skin also protects the body from physical damage and bacterial invasion. The skin has an array of sense organs which sense the external environment, and also cells which can make vitamin D in sunlight. The skin is one of the first systems affected when an animal becomes sick so it is important for anyone working with animals to have a sound knowledge of the structure and functioning of the skin so they can quickly recognise signs of disease.

Thumbnail: The friction ridges on a finger. Image used with permission (CC BY 3.0; Frettie).


  • Ruth Lawson (Otago Polytechnic; Dunedin, New Zealand)