Non-specific Immunity- “1st Line” of Defense

Nonspecific immunity- mechanisms 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 Involved1. 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

Barrier Membranes

Skin

Mechanisms Involved3. 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 out-compete potential pathogens

Lymphatic/1st Line of Defense Review

1. List 2 of the 4 mechanisms that make up the 1st line of defense.

2. Name the 2 mechanical barriers.3. What organ is responsible for filtering

lymph?4. _______________ immunity makes up the

1st line of defense.5. The thoracic duct drains what portion of the

body?6. Saliva and enzymes are part of the

_____________ barriers of the 1st line of defense.

Second Line of Defense

• Fever

• Inflammation

• Phagocytosis

• All work tightly with specific immunity

Fever

Pluses•Inhibit microbial growth•Enhance immune cell performance•Speed tissue repair

Minuses•Malaise•Body aches•chills

Trigger not completely understoodMuscular contraction and constriction of skin blood vessels cause core temperature to rise

“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 Signs-

1.redness- inc. blood volume

2.swelling- inc. capillary permeablilityPhagocytes migrate out of capillaries

3.Heat- inc. blood from deep within body

4.Pain- stimulates pain receptors

• Phagocytes move through blood and lymph and into connective tissues and engulf and destroy cells or pathogens

• Ex. Neutrophils and monocytes

Phagocytosis

•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

2nd line of Defense1. Name the 4 parts of the 2nd line of defense.2. Is the 2nd line Nonspecific or specific?3. _____ increases phagocytic cells4. _____ is the tissue response to injury.5. 4 signs of inflammation?6. Increase in ______ volume causes redness,

swelling, and heat.7. Stimulation of _____ receptors cause pain.8. The process of WBCs to engulf and destroy

pathogens is_______.9. A WBC responsible for phagocytosis is a

_________.