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What is a pathogen? Any agent that causes
disease Koch was the first to
establish how to identify individual pathogens
Identifying pathogens
All of these are caused by communicable diseasesan infectious disease transmissible by direct contact
with an affected individual or the individual's discharges or by indirect means
Pathogens must enter the body to cause disease
SNOT!!-Internal structures Yes, your mucus is the first line of
defense Mucus membranes secrete mucus
Your skin!! releases oil, sweat, waxes that are toxic
to pathogens
The first line of defenseNonspecific immune response
Inflammatory response Activated when any pathogen gets past the first line
of defense
The second line of defense
The body temperature may rise when the body fights off a pathogen.
Obviously called a fever Fevers can slow bacterial and viral growth A fever too high can actually damage proteins
needed to fight infection.
Temperature response
Yes, there are proteins coded for nonspecific defenses.
There are 20 proteins that make up your complementary system
Some of these proteins attack, stab, and destroy pathogen cells
Interferon-a protein released by cells infected with viruses.
Causes nearby cells to make a protein that helps them resist viral infection
Proteins for defense?
The immune system is the cells and tissues that recognize and attack foreign substances in the body and provides the body’s specific defenses.
The Immune SystemSpecific immune response
The immune system fights pathogens, stops the growth and spread of cancers
Made up of several tissues and white blood cells
White blood cells are called lymphocytes Each white blood cell is made in your bone
marrow Each day billions are made
The thymus, located above the heart, is where your T cells mature
The Lymph nodes-collect pathogens and expose them to the lymphocytes
The Immune SystemSpecific immune response
Your lymphocytes can actually recognize foreign invaders
Think about a flu shot Antigens- any substance that the immune system can
recognize and react with Any time your body reacts against an antigen, this is
called an immune response
Recognizing Pathogens
Antigens are located on the surface of a pathogen Lymphocytes have unique receptor proteins on their surface Receptor proteins recognize antigens of the same shape and
bind, rendering the antigen useless. Bacteria can be covered by many different types of antigens,
causing lymphocytes to react.
Recognizing Pathogens
In a nut shell Your body is invaded by pathogens Your macrophage engulf the pathogen and express the
antigen Helper cells bind to the antigen site. This binding causes you to create memory cells and plasma
cells Memory cells “remember” the antigen Plasma cells carry antibodies
Antibodies are highly specialized cells that make defensive proteins
Are in the shape of a Y
The Immune response
Immunity The ability to resist an infectious disease
Vaccination The introduction of antigens into the
body to create immunity
Immunity and vaccination
This is a solution that contains a dead or a weakened pathogen or material from a pathogen
The antigens are still present, therefore your body responds and creates the memory cells.
This response can provide a secondary immune response if affection occurs again.
Common diseases that have been controlled through vaccines
Polio, measles, mumps, tetanus, and diphtheria These vaccines can wear off
Your doctor may recommend a “booster” What are the issues with vaccines?
Vaccines
Fight bacterial infections Do antibiotics help fight virus?
Think of how many times you have a cold or the flu and a Dr. prescribes antibiotics!
When used properly, they can save lives. Remember evolution
Pathogens evolve and cause a very serious issue Antibiotic resistance!!
occurs when bacteria change in some way that reduces or eliminates the effectiveness of drugs, chemicals, or other agents designed to cure or prevent infections. The bacteria survive and continue to multiply causing more harm.
Antibiotics