espirro_2

M130/342
Woman sneezing
CREDIT:  MATT MEADOWS,  PETER ARNOLD  INC./SCIENCE PHOTO LIBRARY

MODEL RELEASED.  Sneeze.  A jet of droplets erupts from  a woman’s nose and mouth.  The sneeze reflex is usually triggered by irritation  of  the  nasal lining  (although  it  can  occur  in  response to bright light,  touching a cold  surface  with  the foot,  or numerous other stimuli). The ejection of fluid helps to cleanse the  respiratory  tract  of dust  filtered out of the air or mucus produced in response to infection.  The reflex is exploited by the cold virus,  which uses sneezing as a means of spreading from one person to the next.

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