Immune System Immune System Overview Flow ChartOverview Flow Chart

CA Biology StandardsCA Biology Standards

Physiology 10a & 10dPhysiology 10a & 10d

Physiology Standard 10bPhysiology Standard 10b

Students know the role of Students know the role of antibodies in the body’s antibodies in the body’s response to infection.response to infection.

Non-Specific ImmunityNon-Specific Immunity

Defenses that are NOT designed to fight a specific disease, but ALL diseases!!

Chemical & Physical Barriers Include:1. Skin – Most important first line of

defense. Physical barrier that keeps pathogens out!

2. Mucus – Contains enzyme (lysosyme) that break down cell walls of many bacteria

3. Sweat & Tears – Contains lysosyme and promote acidic environment that bacteria cannot survive

4. Inflammatory Response: A non-specific defense reaction to tissue damage caused by injury or infection.a. White Blood Cells (Phagocytes) – Detect,

engulf and destroy pathogensb. Fever- Elevated body temperature kills or

slows down growth of pathogens

5. Interferons- Proteins produced by virus-infected cells. Help other cells resist viral infections.

What if the 1What if the 1stst line of defense line of defense doesn’t do the jobdoesn’t do the job??

Specific ImmunitySpecific Immunity

Triggered by specific Antigens to Triggered by specific Antigens to produce Antibodiesproduce Antibodies

– Antigen – A foreign substance that triggers an immune response.

Two Types of Responses:Two Types of Responses:1.1. Humoral ResponseHumoral Response

““Humoral” = In blood or lymphHumoral” = In blood or lymph

2.2. Cell-Mediated Response Cell-Mediated Response

Humoral ResponseHumoral Response

1. In the Blood & Lympha. Lymphocytes produce antibodies

2. Antibodies are Y-Shaped Proteins that help to destroy pathogens

a. Pathogens are foreign threats to the body (virus, bacteria, etc)

b. Antibodies bind to antigens on the pathogens

c. Cause pathogens to clump up

Antigen-binding

sites

AntigenAntibody

Humoral ResponseHumoral Response

3. White blood cells engulf and destroy pathogens (clumps of antibodies & antigens)

4. B cells can be activated by T cells to turn into plasma cells.

5. Plasma cells produce and release large numbers of antibodies into the bloodstream.

6. Some B cells become Memory Cells and can quickly respond if reinfected by same antigen (you can’t get the same cold twice)

Humoral Humoral ResponseResponse

Cell-Mediated Cell-Mediated ResponseResponse

1. Killer T cells kill infected cells to inhibit the reproduction and spread of viruses

Killer T cells are also called Cytotoxic T cells

2. Causes body to reject transplanted organs

Cell-Mediated ResponseCell-Mediated Response

Macrophage

T Cell

Helper T Cell

Killer T Cell

Infected CellAntigens are displayed on surface of macrophage

T cell binds to activated macrophage

T cell, activated by macrophage, becomes a helper T cell

Helper T cell activates killer T cells and B cells

Killer T cells bind to infected cells, disrupting their cell membranes and destroying them

Figure 40-10

VocabularyVocabulary

PathogensPathogens VirusesViruses BacteriaBacteria AntisepticsAntiseptics AntibioticsAntibiotics