Fever may be a component of the nonspecific defense system. Body temperature is regulated by the hypothalamus, which contains a thermoregulatory control center (a "thermostat") that coordinates skeletal muscle shivering and the activity of the sympathoadrenal system to maintain body temperature at about 37° C. This thermostat is reset upward in response to a chemical called endogenous pyrogen. In at least some infections, the endogenous pyrogen has been identified as interleukin-1p, which is first produced as a cytokine by leukocytes and is then produced by the brain itself.

The cell wall of gram-negative bacteria contains endotoxin, a lipopolysaccharide that stimulates monocytes and macrophages to release various cytokines. These cytokines, including interleukin-1, interleukin-6, and tumor necrosis factor, act to produce fever, increased sleepiness, and a fall in the plasma iron concentration.

Although high fevers are definitely dangerous, a mild to moderate fever may be a beneficial response that aids recovery from bacterial infections. The fall in plasma iron concentrations that accompany a fever can inhibit bacterial activity and represents one possible benefit of a fever; others include increased activity of neutrophils and increased production of interferon.

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Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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