RT Book, Section
A1 Dutton, Mark
SR Print(0)
ID 56509465
T1 Chapter 12. Pathology and Psychology
T2 McGraw-Hill's NPTE (National Physical Therapy Examination), 2e
YR 2012
FD 2012
PB The McGraw-Hill Companies
PP New York, NY
SN 9780071771290
LK accessphysiotherapy.mhmedical.com/content.aspx?aid=56509465
RD 2024/04/20
AB Together  with  a  series  of  physical  barriers  (the  skin,  mucous  membranes,  tears,  and  stomach  acid),  the  immune  system  helps  to  defend  the  body  against  foreign  or  harmful  substances  that  attempt  to  infiltrate  it  (Table  12-1).  Such  substances  include  microorganisms  (bacteria,  viruses,  and  fungi),  parasites  (such  as  worms),  cancer  cells,  and  even  transplanted  organs  and  tissues.  Antigens  are  entities  within  or  on  bacteria,  viruses,  other  microorganisms,  or  cancer  cells  that  stimulate  an  immune  response  in  the  body.  Antigens  may  also  exist  independently—eg,  as  pollen  or  food  molecules.  A  normal  immune  response  consists  of  the  initial  recognition  of  a  foreign  antigen,  and  the  mobilization  of  forces  to  defend  against  it.