immune system
DESCRIPTION
Immune System. A Boo Boo lets in germs. Like…Bacteria. Or a virus. A germ is still a germ…. Pathogen =agent that causes disease 2 . Antigen = foreign particle that triggers an immune response - PowerPoint PPT PresentationTRANSCRIPT
Immune SystemImmune System
A Boo Boo lets in germsA Boo Boo lets in germs
Like…BacteriaLike…Bacteria
Or a virusOr a virus
A germ is still a germ….A germ is still a germ….
1.1. PathogenPathogen=agent that causes disease=agent that causes disease
22. Antigen. Antigen= foreign particle that triggers = foreign particle that triggers an an
immune responseimmune response
- often they are proteins - often they are proteins on on the surface of viruses the surface of viruses and and bacteria bacteria
Your Body’s Defenses Your Body’s Defenses AgainstAgainstDiseaseDisease
Nonspecific Defenses: Attack all Nonspecific Defenses: Attack all pathogens and antigens the same pathogens and antigens the same wayway
Specific Defenses: Immune Response Specific Defenses: Immune Response – Attack pathogens that get past the – Attack pathogens that get past the nonspecific defenses nonspecific defenses
Nonspecific DefensesNonspecific Defenses
This means that the identity This means that the identity of the pathogen/antigen is of the pathogen/antigen is not not importantimportant. The response is . The response is the same if a bacteria, virus, the same if a bacteria, virus, splinter or bullet invades the splinter or bullet invades the body.body.
Nonspecific DefensesNonspecific DefensesFirst Line DefensesFirst Line Defenses
Skin: Forms a physical barrier to pathogensSkin: Forms a physical barrier to pathogens-oils and sweat make skin acidic – -oils and sweat make skin acidic –
inhibits inhibits the growth of pathogens the growth of pathogens -lysozyme-enzyme found in sweat and -lysozyme-enzyme found in sweat and
tears tears digests bacterial cell walls digests bacterial cell walls Mucus Membranes-layers of tissue which Mucus Membranes-layers of tissue which
secrete mucussecrete mucus - found in body openings and the - found in body openings and the
respiratoryrespiratory systemsystem - mucus traps pathogens - mucus traps pathogens
Nonspecific DefensesNonspecific DefensesSecond Line DefensesSecond Line Defenses Inflammatory ResponseInflammatory Response
Damaged cells release histamines – chemical cry for helpDamaged cells release histamines – chemical cry for help
- histamines cause blood vessels to dilate (open) bringing - histamines cause blood vessels to dilate (open) bringing
blood to the area.blood to the area.
- the dilated blood vessels become leaky releasing fluid and white - the dilated blood vessels become leaky releasing fluid and white blood cells in the infected areablood cells in the infected area
- causes swelling and redness in the damaged area- causes swelling and redness in the damaged area
- pus – fluid and dead cells forms- pus – fluid and dead cells forms White Blood cells White Blood cells
- Macrophages – - Macrophages – “Big Eaters” engulf and kill pathogens“Big Eaters” engulf and kill pathogens
- Neutrophils-- Neutrophils-engulf bactera and release chemicals that engulf bactera and release chemicals that kill the bacteria and themselves. kill the bacteria and themselves.
-- Natural Killer Cells –Natural Killer Cells – recognize and kill virus infected recognize and kill virus infected
cells and tumorscells and tumors
Textbook page 925Textbook page 925
Histamines are released Blood vessels dilateHistamines are released Blood vessels dilate
and leak and leak
MacrophageMacrophage
Nonspecific DefensesNonspecific DefensesSecond Line Defenses (continued)Second Line Defenses (continued)
Temperature Response - Temperature Response - Fever – Fever –
-Body temp increases in response to infection-Body temp increases in response to infection
-pathogenic bacteria don’t grow well at higher temp-pathogenic bacteria don’t grow well at higher temp
ProteinsProteins - - Complement Proteins: Complement Proteins: kill pathogens by punching a kill pathogens by punching a hole hole
in the cell membranein the cell membrane
- Intrerferon: - Intrerferon: a protein released by cells infected by virusesa protein released by cells infected by viruses
-causes nearby cells to release an enzyme preventing the virus -causes nearby cells to release an enzyme preventing the virus
from reproducingfrom reproducing
Fevers help eliminate Fevers help eliminate pathogenspathogens
Specific DefensesSpecific Defenses
Third Line of DefenseThird Line of Defense
Specific DefensesSpecific Defenses
- identity of pathogen/- identity of pathogen/
antigen must be knownantigen must be known
- the specific immune - the specific immune
response is tailored to response is tailored to
the specific pathogenthe specific pathogen
Specific DefensesSpecific DefensesMacrophage Links Nonspecific to Macrophage Links Nonspecific to
SpecificSpecific
When a macrophage engulfs a When a macrophage engulfs a pathogen, it displays the viral pathogen, it displays the viral antigen on its surfaceantigen on its surface
The antigen is joined to a MHC (Major Histocompatibility Complex)
The MHC is a protein on the surface ofall vertebrate cells
The anitgen must be bound to the MHC for the Helper T Cell to recognize it
Specific DefensesSpecific DefensesHelper T CellsHelper T Cells
Receptor proteins on helper T cells (TReceptor proteins on helper T cells (THH) )
bind to viral antigens displayed on the bind to viral antigens displayed on the macrophagemacrophage
causes macrophage tocauses macrophage to release Interleukin1release Interleukin1
Interleukin1 activates Interleukin1 activates
the helper T cells (Tthe helper T cells (THH) )
Specific DefensesSpecific DefensesHelper T Cells Helper T Cells continuedcontinued
Activated helper T cells (TActivated helper T cells (THH) release proteins ) release proteins called cytokines which activate cytotoxic T cells called cytokines which activate cytotoxic T cells (T(TCC) and B cells) and B cells
The activated (TThe activated (TCC) and B cells begin to divide) and B cells begin to divide
Specific Defenses Specific Defenses Cell Mediated ResponseCell Mediated Response
Receptor proteins on theReceptor proteins on the
cytotoxic T cells (Tcytotoxic T cells (TCC) bind to ) bind to
viral antigens displayed by viral antigens displayed by
infected cellsinfected cells Cytotoxic T cells (TCytotoxic T cells (TCC) punch a ) punch a
hole in the cell’s membranehole in the cell’s membrane Your body produces many Your body produces many
cytotoxic T cells (Tcytotoxic T cells (TCC) )
- each specific to a particular antigen- each specific to a particular antigen
Specific DefensesSpecific DefensesAntibody Mediated ResponseAntibody Mediated Response
B cells divide and develop into B cells divide and develop into
plasma cellsplasma cells Plasma cells release large numbersPlasma cells release large numbers
of antibodies of antibodies AntibodiesAntibodies bind to antigens on bind to antigens on
pathogenspathogens Antibodies cause pathogens to clumpAntibodies cause pathogens to clump
holding them until macrophages holding them until macrophages
can engulf themcan engulf them Antibodies are specific to a particular pathogen-your body Antibodies are specific to a particular pathogen-your body
produces the antibodies in response to infectionproduces the antibodies in response to infection
The Specific Defense has The Specific Defense has two phasestwo phases
Primary Immune Primary Immune Response:Response:
--Occurs when the body Occurs when the body has never has never encountered a encountered a pathogen /antigen pathogen /antigen before. before. -Immune system goes -Immune system goes through all of the stepsthrough all of the steps
-After the threat has -After the threat has passed, passed, MEMORY Cells MEMORY Cells are made.are made.
Secondary Secondary Immune Immune Response:Response:The next time the The next time the pathogeninvades pathogeninvades MEMORY Cells MEMORY Cells identify identify the invader and a the invader and a massive volume of massive volume of antibodies are released, antibodies are released, destroying the invader destroying the invader before you feel ill. before you feel ill.
You are immune!You are immune!
VaccinesVaccines
Polio 1952 60,000 cases in the US 3000 fatalities1955 Salk vaccine1979 eliminated in US
How do vaccines work?How do vaccines work? VaccinesVaccines are made up of weakened are made up of weakened
viral particles.viral particles. The weakened particles stimulate a The weakened particles stimulate a
small number of antibodies and small number of antibodies and memory cells to be produced. memory cells to be produced. Primary Immune ResponsePrimary Immune Response
When a the pathogen attacks, the When a the pathogen attacks, the antibody production is larger. antibody production is larger.
Secondary Immune ResponseSecondary Immune Response
Immune ResponseImmune Response
VocabularyVocabulary Pathogen B cells T cellsPathogen B cells T cells MacrophagesMacrophages Nonspecific DefenseNonspecific Defense VaccinesVaccines Primary Immune ResponsePrimary Immune Response Secondary Immune ResponseSecondary Immune Response