Immune System Part Immune System Part IIII

Physiology Standards: Physiology Standards: 10 a-e10 a-e

Once Once insideinside the body pathogens the body pathogens are met with several defense are met with several defense

systemssystems

The Immune The Immune SystemSystem Nonspecific defensesNonspecific defenses continuedcontinued

– If the skin is “broken” you will get what If the skin is “broken” you will get what is called the is called the inflammatory responseinflammatory response Blood flow is increased as millions of white Blood flow is increased as millions of white

blood cells flood the infected areablood cells flood the infected area An elevated body temp. (An elevated body temp. (feverfever ) is another ) is another

form of defense creating a poor environment form of defense creating a poor environment for pathogensfor pathogens

A fever of 100 degrees F causes white blood A fever of 100 degrees F causes white blood cells to mature quicker while a fever of 103 cells to mature quicker while a fever of 103 or higher could cause some serious damage or higher could cause some serious damage or even deathor even death

The Lymphatic SystemThe Lymphatic System Your immunes system’s Your immunes system’s

“pipeline” for “pipeline” for transporting and transporting and housing housing specialized specialized cellscells for fighting for fighting infections are found in infections are found in your your lymphatic systemlymphatic system

The Immune The Immune SystemSystem Specific DefensesSpecific Defenses of the Immune System of the Immune System

– When the body attacks foreign objects that When the body attacks foreign objects that have made it into your body it is called the have made it into your body it is called the immune responseimmune response

– A substance that “triggers” an A substance that “triggers” an immune immune responseresponse is known as an is known as an antigenantigen

– There are two types There are two types specialized cellsspecialized cells that that attack attack antigensantigens B~ lymphocytes (B-cells)-B~ lymphocytes (B-cells)-produce produce

proteins that inactivate pathogens that proteins that inactivate pathogens that have not infected cells yethave not infected cells yet

T~ lymphocytes (T-cells)-T~ lymphocytes (T-cells)-destroy body destroy body cells that cells that areare infected with pathogens infected with pathogens

AntibodiesAntibodies

B~ lymphocytesB~ lymphocytes are responsible for making are responsible for making antibodiesantibodies which which are specialized proteins that are specifically designed to destroy are specialized proteins that are specifically designed to destroy specific pathogens by recognizing specific pathogens by recognizing antigen binding sitesantigen binding sites

AntigenAntigenbinding binding

sitessites

AntigenAntigen

AntibodyAntibody

AntibodiesAntibodies AntibodiesAntibodies are are proteins that recognize proteins that recognize

and “bind” to antigens and “bind” to antigens Once the infection is destroyed, Once the infection is destroyed,

memory B-cellsmemory B-cells remain capable of remain capable of producing that specific antibodyproducing that specific antibody in in case you receive the same infectioncase you receive the same infection– It is estimated that a healthy adult has It is estimated that a healthy adult has

around 100 million different types of around 100 million different types of antibodies to fight infectionantibodies to fight infection

– The more “exposure”, the more The more “exposure”, the more antibodies you create in your “library”antibodies you create in your “library”

B Cells & B Cells & Humoral Humoral ImmunityImmunity

Surface Surface proteins on proteins on antigensantigens trigger trigger memory memory B B CellCell productionproduction

Activated Activated B B cellscells release release millions of millions of antibodiesantibodies

Antibodies “clump” the Antibodies “clump” the antigensantigens and and phagocytesphagocytes “eat” the pathogen clumps“eat” the pathogen clumps

T CellsT Cells – “Pathogen – “Pathogen Destroyers”Destroyers” Once an Once an antigenantigen

or infected cell is or infected cell is in the body in the body T T CellsCells use their use their surface proteins surface proteins to recognize the to recognize the antigen and start antigen and start making moremaking more T T CellsCells

Activated T CellsActivated T Cells remain in the remain in the body forever body forever waiting for a waiting for a future invasionfuture invasion

T Cells use many T Cells use many methods to “kill” the methods to “kill” the antigenantigen or or infected cellinfected cell directlydirectly

Acquired ImmunityAcquired Immunity Humans have long wanted to prepare Humans have long wanted to prepare

people people beforebefore they become infected they become infected with a disease, especially when the with a disease, especially when the disease could potentially kill themdisease could potentially kill them

A A vaccinationvaccination can be a: can be a:– A weakened form of the original pathogenA weakened form of the original pathogen– A “killed” pathogen that still has it’s A “killed” pathogen that still has it’s

shape for the shape for the immune responseimmune response– An An alternatealternate form of the disease such as form of the disease such as

cowpoxcowpox to trigger the immune response to trigger the immune response for for smallpoxsmallpox

Acquired ImmunityAcquired Immunity Two Types of Immunity:Two Types of Immunity:

– Active ImmunityActive Immunity – the – the type of immunity that is type of immunity that is generated by the body generated by the body following exposure to a following exposure to a pathogen or after a pathogen or after a vaccinationvaccination

– Passive ImmunityPassive Immunity – can – can be utilized by injecting be utilized by injecting antibodies to the antibodies to the infection that were infection that were created by another created by another animalanimal

Antigens in a Antigens in a vaccinevaccine triggertriggerthe the immune responseimmune response and and Memory B Cells Memory B Cells are madeare made

Diseases that Weaken the Immune Diseases that Weaken the Immune SystemSystem

Your Your immune systemimmune system is your internal is your internal defense system against defense system against allall infections infections and pathogens, right?and pathogens, right?

What happens if a pathogen What happens if a pathogen attacksattacks your Immune System?your Immune System?

LeukemiaLeukemia is cancer of the bone marrow is cancer of the bone marrow– Leukemia weakens bones and makes them Leukemia weakens bones and makes them

unable to produce disease fighting unable to produce disease fighting white white blood cellsblood cells

HIVHIV (Human Immunodeficiency Virus) (Human Immunodeficiency Virus) is anotheris another

HIVHIV HIV HIV

enters enters the the body body through through direct direct contact contact and and sharing sharing of blood of blood or fluidsor fluids

HIV HIV killskills T-Cells until T-Cells until the host’s immune the host’s immune system is so weak that system is so weak that the host is unable to the host is unable to fight off mild infectionsfight off mild infections