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Defending Infection. Homework Due Thursday. Complete 35.2 Worksheet. Pathogens. Spread of diseases. Different for different diseases Sneezing Coughing Physical contact Exchange of body fluids Infected animals Droplets in the air/doorknobs WASH YOUR HANDS!. Symbionts vs. Pathogens. - PowerPoint PPT Presentation
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Defending Infection
Homework Due Thursday
Complete 35.2 Worksheet
PathogensNAME CHARACTERISTIC DISEASESViruses Nonliving, insert
genetic material into host cell; take over host cell functions
Common cold, flu, chickenpox, warts
Bacteria Release toxins that interfere with normal host cell activity
Strep throat, anthrax
Fungi Infection on surface of skin, mouth, throat
Ringworm, thrush
Protists Take nutrients from host; inflict damage to cells and tissues
Malaria, intestinal diseases
Parasites Wormlike; enter through mouth; absorb nutrients through intestinal tract
Trichinosis, hookworm, elephantiasis
Spread of diseasesDifferent for different diseases
SneezingCoughingPhysical contactExchange of body fluidsInfected animals
Droplets in the air/doorknobsWASH YOUR HANDS!
Symbionts vs. Pathogens
Symbionts are harmless to the bodySometimes beneficial
Bacteria in the Large Intestines help with digestion “Good guys” grow and reproduce without causing problems“Bad guys” cause problems
Destroy cells of their hostRelease poisons that kill host cellsWorms might block blood flow or take nutrients
First Line of DefenseDead cells!Skin make penetration of pathogens very difficultActs as “armor” to defend the bodyHoles in your “armor” include:
MouthEyesNose
First Line of DefenseSaliva, mucus and tears contain lysozyme
Enzymes that breaks down bacterial cell walls
Mucus traps pathogens in nose and throatCilia push the trapped pathogens to the stomach where they are swallowed.
Inflammatory ResponseInfected areas become red and painfulPathogens stimulate cells to release histamines
Increase blood flow and nutrient fluids
Swelling occurs when fluids leak from expanded blood vesselsHow does this compare to sprained ankle? Or a broken finger?
Inflammatory ResponseWhite blood cells move into infected tissues
Phagocytes are WBCs that engulf (eat) and destroy bacteria
Interferons? Interfere with the growth of virusesDon’t allow synthesis of viral cells
FeverSlows pathogens and speeds up immune system
Immune SystemBasis is to differentiate between domestic and foreign Domestic signals notify the Immune System they are good for the bodyForeign objects are unable to replicate passwordRecognizing “self” is vital to the success of the Immune System
Immune SystemMust be able to respond to “non-self”Remembers any specific invader
Immune system memory allows for the Immune System to respond to it quicker next time
Example: Ability to do “Times Tables”
Immune SystemAntigens are foreign substances that trigger the immune systemAntibodies are created to “tag” specific antigens to be destroyed by phagocytes
Homework Due Thursday
Complete 35.2 Worksheet