Some anatomy geeks get a kick out of asking unsuspecting people to name the largest system or external organ in the body. The answer: The integumentary system, of course, which includes the skin, hair, nails, and sebaceous and sweat glands (Springhouse 2002). Its main function is to protect the body from “the outside world” (bacteria, for example), but it also eliminates waste products, regulates body temperature and retains body fluids (AAAS 2017).

The skin produces vitamin D in the presence of sunlight and is also a sense organ, with nerve endings that detect pain, touch, heat, cold and pressure (Krapp 2006). The integumentary system helps clients “sweat it all out” with you while sensing the world around them in a way that most of us take for granted. Read on to find out more.

  • The skin is a “dynamic, multilayered organ” that accounts for 15%–20% of total body weight. If you were to lay it flat, the skin would cover a surface of 1.5–2 meters (Hamm 2015).
  • In 1 year, humans shed over 8 pounds of dead skin (Smith 2015).
  • Goose bumps are a special feature of the integumentary system. Arrector pili muscles extend from the skin and attach to each hair follicle. These muscles contract in response to touch, emotion and changes in temperature (Smith 2015).
  • Everyone has a unique sweat “fingerprint,” a blend of 373 volatile compounds. However, the two types of sweat glands—apocrine and eccrine—are universal. Eccrine glands cover most of the body, but apocrine glands occur only in the armpits and genital region (Festa 2015).
  • A “properly balanced diet” is a prime way to keep the integumentary system healthy, but if supplementation is needed, targeting any deficiencies in micro- or macronutrients may help; vitamins C, E and A, the B vitamins, and fatty acids are good options to consider (Szyszkowska et al. 2014).



Krapp, K.M. (Ed.) 2006. Integumentary system. In Gale Encyclopedia of Nursing and Allied Health. Accessed Aug. 28, 2017:

Hamm, R.L. 2015. Text and Atlas of Wound Diagnosis and Treatment. China: McGraw-Hill Education.

Springhouse. 2002. Lippincott Professional Guides: Anatomy & Physiology (2nd ed.). Ambler, PA: Lippincott, Williams & Wilkins.

Smith, C. 2015. Anatomy and physiology: Five things about the integumentary system. Accessed Aug. 18, 2017:

Szyszkowska, et al. 2014. The influence of selected ingredients of dietary supplements on skin condition. Advances in Dermatology and Allergology (3), 174–81.

Joy Keller

Joy Keller is executive editor of IDEA Fitness Journal and IDEA Fit Business Success, and is also a certified personal trainer, indoor cycling instructor, yoga teacher (RYT 200) and Reiki Master.

Leave a Comment

When you buy something using the retail links in our content, we may earn a small commission. IDEA Health and Fitness Association does not accept money for editorial reviews. Read more about our Terms & Conditions and our Privacy Policy.