Integumentary system as a diagnostic aid
Explain how the integumentary system can be used as adiagnostic aid.
The integumentary system is useful in diagnosis because it is observed easily and often reflects events occurring in other parts of the body. For example, cyanosis, a bluish color to the skin caused by decreased blood O2 content, is an indication of impaired circulatory or respiratory function. A yellowish skin color, called jaundice (jawn′ dis), can occur when the liver is damaged by a disease, such as viral hepatitis. Normally, the liver secretes bile pigments, which are products of the breakdown of worn-out red blood cells, into the intestine. Bile pigments are yellow, and their buildup in the blood and tissues can indicate impaired liver function.
Rashes and lesions in the skin can be symptoms of problems elsewhere in the body. For example, scarlet fever results when bac-teria infecting the throat release a toxin into the blood that causes a reddish rash on the skin. The development of a rash can also indicate an allergic reaction to foods or to drugs, such as penicillin.
The condition of the skin, hair, and nails is affected by nutri-tional status. In vitamin A deficiency, the skin produces excess keratin and assumes a characteristic sandpaper texture, whereas in iron-deficiency anemia the nails lose their normal contour and become flat or concave (spoon-shaped).
Hair concentrates many substances that can be detected by laboratory analysis, and comparison of a patient’s hair with a “normal” hair can be useful in certain diagnoses. For example, lead poisoning results in high levels of lead in the hair. However, the use of hair analysis to determine the general health or nutritional status of an individual is unreliable.