The Biotic Environment - Effects on Health

BIOTIC ENVIRONMENT - EFFECTS ON HEALTH

• physical activity
• nutrition
• stress management
• mental stimulation
• strong imune system

• disease=disturbances homeostasis
  • exogenous
  • endogenous
  • chronic, acute

Immunity=ability of body - fight infection/foreign invaders by producing antibodies/killing infected cells

Immune system=maintaining homeostasis - recognising harmful from non-harmful organisms - appropriate response

Pathology=study essential nature - diseases+structural+functional changes produced by them

Antigens=substance, foreign to body - evokes immune response. alone/after forming complex - large molecule - capable binding with product, immune system.

• identification structures+toxins, pathogens exhibit - cause harm

• organs - immune system
  • tonsils+adenoids
  • lymphatic vessels+lymph nodes
  • thymus
  • spleen
  • peyer's patches
  • appendix
  • bone marrow

• leukocytes=white blood cells
  • polymorphonuclear granulocytes - neutrophils, eosinophils, basophils
  • monocytes
  • lymphocytes

• lymphatic system=lymph glands/nodes+lymphatic vessels

• defense
  • skin
  • nonspecific immune response
  • specific immune response

• skin
  • physical barrier=hard penetrate - indidestible keratin
  • chemical barrier=tears, sweat, saliva, mucous

• nonspecific immune response=no matter what invader is
  • phagocytosis - macrophages
  • natural cell killers - kill invading+damaged cells
  • inflammation - release histamine by leukocytes
    • histamine released - increases blood flow
    • causes capillaries, leak. releases phagocytes+clotting factors - wound
    • phagocytes engulf bacteria, dead cells+cellular debris
    • platelets move out capillaries - seal wounded area

• specific immune response
  • response - specific pathogen/antigen
  • creation, specific antibodies

• antibodies
  • y shaped protein molecule
  • variable+constant regions
  • variable recognises antigens
  • heavy+light chains
  • produced - B lymphocytes
  • recognise antigens - bind to+ deactivate

• immune response
  • antigen infects cells
  • macrophage ingests antigen+displays portion - surface
  • helper T cell recognises antigen - surface macrophage - become active
  • active helper T cell activates cytotoxic T cells+B cells
  • cytotoxic T cells divide - active cytotoxic T cells+memory T cells
  • active cytotoxic T cells kill infected cells
  • B cells divide - plasma cells+memory B cells
  • plasma cells produce antibodies - deactivate pathogen
  • memory T+memory B cells remain - speed up response, same antigen reappears
  • suppressor T cells stop immune response…