IMMUNE SYSTEM INON-SPECIFIC DEFENSE

PP. 957-960

FUNCTION

• Fights pathogens to prevent infections and disease

• Works with the lymphatic system (collects fluid and returns it to the blood)

KOCH’S POSTULATES

• Study page 957

STRUCTURES

• Bone marrow: produces blood cells

• Lymphocytes: wbc • Thymus: mature wbc• Lymph nodes: stores wbc• Spleen: contains wbc that clean

out pathogens as blood filters through

WHITE BLOOD CELLS (wbc)• Also called leukocytes• Type of wbc present indicates specific

disease or have specific job

IE. Neutrophils respond to bacteria

INITIATING THE IMMUNE SYSTEM

• pathogens: cause disease

- viruses: protein shell containing DNA or

RNA

- bacteria, protists, fungi

FIRST LINE OF DEFENSE

• Skin: block entry• mucous membranes: trap

pathogens and move them out of the body

• stomach acids: destroys pathogens

SECOND LINE OF DEFENSE• Inflammatory response

1. Injured cells release a chemical signal

called histamine to increase blood flow to

area

2. platelets cause clotting trapping pathogens

3. Area swells, becomes warm, and

macrophages/phagocyte (wbc) move in and

engulf bacteria

• interferons: enzymes that stop virus protein production

• fever: increase activity of wbc