immune_system2012

Immune System: 

Immune System 10/14/2011

What is Immunity?: 

What is Immunity?

Immunity: 

Immunity Immunity The ability of the body to fight infection and/or foreign invaders by producing antibodies or killing infected cells . Could be through immunizations. Immune System The system in the body responsible for maintaining homeostasis by recognizing harmful organisms and then to produce an appropriate response.

Foreign Invaders: 

Foreign Invaders Called Pathogens Viruses, bacteria or other living thing that causes disease/immune response. Antigens These are any cell markers- even your own can cause an immune response.

Slide 5: 

Antigens all cells have surface markers called antigens. body can recognise these as self or non-self (foreign)

Parts of the Immune System: 

Parts of the Immune System 10/14/2011 Blood - White Blood Cells (Leukocytes) in particular. Lymph nodes ( next slide) Thymus Gland – Produces T Lymphocytes Bone Marrow – Produces B Lymphocytes This is a Lymphocyte, it can be either a T or B

Lymphatic System: 

Lymphatic System 10/14/2011

How does the body fight infection/foreign invaders?: 

How does the body fight infection/foreign invaders? The Body ’ s THREE lines of Defense First Line of Defense – The Skin Provides Physical and Chemical barriers Physical – hard to penetrate, made of indigestible keratin Chemical – tears, sweat

First lines of defence: 

First lines of defence skin prevents entry tears antibacterial enzymes saliva antibacterial enzymes stomach acid low pH kills harmful microbes mucus linings traps dirt and microbes “good” gut bacteria out compete bad

Second Line of Defense – Nonspecific Immune Response : 

Second Line of Defense – Nonspecific Immune Response These are defenses the body uses no matter what the invader may be. These defenses include: Phagocytosis – done by Macrophages Natural Cell Killers Inflammation - caused by release of Histamine from leukocytes Fever – caused by histamines. The fever (high temp) kills invaders by denaturing their proteins. Macrophage : A phagocytic cell found in the liver, spleen, brain and lungs. Travels to all areas of the body to find and eat pathogens .

Phagocytes: Police the Fluid Areas : 

Phagocytes: Police the Fluid Areas 2 nd Line of defense Macrophages are the chief phagocytic cells Free macrophages wander throughout a region in search of cellular debris Neutrophils become phagocytic when encountering infectious material Eosinophils are weakly phagocytic against parasitic worms 10/14/2011

2nd Line of Defense: Mobilize Quickly: 

2 nd Line of Defense: Mobilize Quickly ANY INVADER= nonspecific The body uses nonspecific cellular and chemical devices to protect itself Phagocytes and natural killer (NK) cells Antimicrobial proteins in blood and tissue fluid Inflammatory response enlists macrophages, WBCs , and chemicals Harmful substances are identified by surface markers unique to infectious organisms 10/14/2011

The Inflammatory Response (Click for movie): 

The Inflammatory Response (Click for movie) 10/14/2011 The inflammatory response is triggered whenever body tissues are injured Prevents the spread of damaging agents to nearby tissues Disposes of cell debris and pathogens Sets the stage for repair processes The four cardinal signs of acute inflammation are: Redness Heat Swelling Pain

Third Line of Defense – Specific Immune Response: 

Third Line of Defense – Specific Immune Response This is a specific response to a specific pathogen-antigen . The response involves the creation of Antibodies It has two separate responses that work together: B cells: humoral immunity (body fluid) T cells: cellular immunity It is the most complex and slowest to respond It has to activate cells for each new invader (antigen) On first exposure it takes ~ 10 days to reach peak levels

Antibodies: 

Antibodies Y-shaped protein molecule. Produced by B-Lymphocytes Function: Recognize antigens, bind to and deactivate them .

How an antibody operates/works?: 

How an antibody operates/works? Deactivation of a bacterium by an antibody.

Molecule structure (Antibody): 

Molecule structure (Antibody) 10/14/2011

The Pathway of Specific Immune Response: 

The Pathway of Specific Immune Response Pathogens Pathogens eaten by Macrophage Displays portion of Pathogen on surface Helper-T cell recognizes Pathogen Step 1 Step 2 Step 3

Slide 19: 

Activates B- Cell Activates Cytotoxic T - Cell Memory B-Cell Memory T-Cell Kills Infected Cells Antibodies 

Cellular Immunity .vs. Antibody (Humoral) Immunity: 

Cellular Immunity .vs. Antibody ( Humoral ) Immunity Carried out by T-Cells Infected cells are killed by Cytotoxic T –Cells. Carried out by B-cells Antibodies are produced and dumped into blood stream. Antibodies bind to antigens and deactivate them. Cellular Immunity Humoral Immunity

Primary vs. Secondary Immune Response: 

Primary vs . Secondary Immune Response Primary Immune Response This is a response to an invader the First time the invader infects the body. No measurable immune response for first few days. Next 10 – 15 days antibody production grows steadily Secondary Immune Response A more rapid response to an invader the 2 nd time it invades the body. Antibody production increases dramatically and in a much shorter time period..

Primary .vs. Secondary Immune Response: 

Primary .vs. Secondary Immune Response

Slide 23: 

Fig. 35.19, p.594 10/14/2011 Some transcripts become new viral RNA; others are translated into proteins. Together, they self-assemble into new virus particles. Virus particles that bud from an infected cell may attack another cell. Viral DNA forms by reverse transcription of viral RNA. Viral RNA enters a T cell. The viral DNA becomes integrated into host cell’s DNA. DNA, including the viral genes, is transcribed. lipid envelope with proteins viral RNA viral enzyme (reverse transcriptase) viral coat proteins 25–30 µm nucleus viral DNA viral RNA viral proteins a b c d e f

Overview of the Immune System: 

Overview of the Immune System 10/14/2011