Download Non-specific Immunity

Non-specific Immunity- “1st
Line” of Defense
Nonspecific immunitymechanisms of the
body that respond to
many different
pathogens or invaders
Nonspecific Immunity
• Prevent or destroy pathogens
• Attacks anything that is considered “not
self”- viruses, bacteria, prions
• Attacks pathogen immediately
• General defense
Mechanisms Involved
1. Species Resistance- genetic characteristics which prevent
an organism from contracting a disease
Ex. Dogs cannot contract mumps
2. Mechanical Barriers- “castle wall” of our body of densely
packed cells and other materials which protect from invasion,
sloughed off (10B skin cells/day=250 g./year)
Ex. Skin, mucous membranes
If either is broken, pathogens can enter.
“First Line” of Defense
• Mechanical barrier on all surfaces of body
exposed to external world
• What are they?
– Skin
– Mucous membranes—nasal, respiratory
– Lining of mouth
– Lining of gut
– Lining of vagina/urethra
– Surface of eye
Skin
Barrier
Membranes
Mechanisms Involved
3. Chemical Barriers- chemicals that interfere with the
production of a pathogen
Ex. Mucus- sticky, traps pathogen
Enzymes- proteins that destroy pathogen
HCl- stomach acid- lowers pH to kill pathogen
4. Resident microbes-have commensal or mutualistic
bacteria and fungi that are normally present and outcompete potential pathogens
Second Line of Defense
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Fever
Inflammation
Phagocytosis
All work tightly with specific immunity
Fever
Trigger not completely understood
Muscular contraction and constriction of skin blood vessels cause core temperature to rise
Pluses
• Inhibit microbial
growth
• Enhance immune cell
performance
• Speed tissue repair
Minuses
• Malaise
• Body aches
• chills
“Breaking” fever or “crisis of fever”:
• body begins to cool by sweating,
• “color returns” as blood vessels in skin open
• Indicates infection is overcome
Inflammation
• Response to tissue damage from any
source (burn, cut, pathogen, other??)
4 Cardinal Signs1. redness- inc. blood volume
2. swelling- inc. capillary permeablility
Phagocytes migrate out of capillaries
3. Heat- inc. blood from deep within body
4. Pain- stimulates pain receptors
Phagocytosis
• Phagocytes move through blood and
lymph and into connective tissues and
engulf and destroy cells or pathogens
• Ex. Neutrophils and monocytes
•Langerhans cells in skin
•Phagocytes in blood
•Microglial cells in CNS
Great review of “Body Defenses” or
Non-specific Immunity
http://fajerpc.magnet.fsu.edu/Education/2010/2010_INDEX.HTM