Читать книгу Understanding Anatomy and Physiology in Nursing - John Knight - Страница 71

Prisha is a 19-year-old undergraduate student and for the last week has been suffering from a sore throat. Initially she thought she was suffering from a common cold, but on looking at her throat in a mirror she was horrified to see that her tonsils were enlarged and purulent. The campus GP recorded her tympanic temperature at 39.1°C and, on noting her inflamed tonsils, took mouth swabs and palpated her cervical lymph nodes (in the neck), and noted they were swollen and tender. She was immediately diagnosed with tonsillitis, put on a course of antibiotics and advised to rest. A few days later Prisha was informed that the throat swabs had revealed she had streptococcal tonsillitis; her GP was happy that this was responding well to the prescribed antibiotics.

Throughout this chapter we have seen that homeostasis is reliant on negative feedback mechanisms to minimise deviations from the physiological set point to constrain a variable within its normal range. However, in some physiological situations it is desirable for the overall health of the body to temporarily deviate dramatically from a physiological set point.