RT Book, Section
A1 Butts, John D.
A2 Reisner, Howard M.
SR Print(0)
ID 1173768076
T1 Environmental Injury
T2 Pathology: A Modern Case Study, 2e
YR 2020
FD 2020
PB McGraw-Hill Education
PP New York, NY
SN REISNERPATHOL
LK accessmedicine.mhmedical.com/content.aspx?aid=1173768076
RD 2024/04/19
AB External  factors,  forces,  and  agents  play  a  significant  role  in  the  causation  of  human  disease.  The  environment  in  which  we  live  is  hardly  benign  and  we  are  constantly  exposed  to  its  potential  hazards.  These  include  physical,  chemical,  thermal,  and  electrical  forces  as  well  as  ionizing  radiation.  Noncommensal  microbiological  organisms  are  also  external  agents.  While  within  the  spectrum  of  human  disease  there  are  conditions  where  external  factors  have  little  or  no  role,  such  as  some  inherited  disorders  of  metabolism  or  the  muscular  dystrophies,  in  most  human  afflictions  external  factors  interact  with  host  factors  to  produce  disease.  Certain  lung  cancers  are  linked  to  cigarette  smoking  and  liver  disease  is  a  well-documented  consequence  of  heavy  alcohol  consumption,  yet  in  spite  of  the  clear  evidence  that  links  these  two  agents  to  these  diseases,  it  is  also  the  case  that  only  a  minority  of  smokers  and  drinkers  respectively  develop  them.  At  the  other  end  of  the  spectrum  lie  the  instances  where  external  forces  or  agents  are  essentially  the  only  factors  as  in  trauma  from  a  natural  catastrophe  like  an  earthquake  or  a  human-made  event  such  as  a  motor  vehicle  crash.