Immune System Notes

Textbook Online

Class Notes

Function: defense against the body’s invaders. 

Fight off disease.  

Help keep the body healthy.


Microorganisms that spread and cause disease.

*Early in history- thought to be from evil spirits

Passed 4 ways- person to person, environment, animal bite & contaminated objects.

Pathogens- disease causing organisms.  infectious

systemic-whole body infection

antigens- specific markings on pathogens to say what type it is. 

-anything that triggers immune system.

-similar to a barcode

*4 kinds:

bacteria- 1 cell organisms   ie: strep throat, tetanu, t.b., plague

virus- nonliving proteins, need living cell to reproduce. 

fungi-  molds, yeasts.   ie: athlete’s foot

protists- protozoa   ie: malaria 

*antiseptic- kills bacteria on living (skin)

*disenfectant- kills bacteria on nonliving (objects)

Lines of defense:

*1st Line of defense- Barriers:   Non-specific

Skin- oil/sweat-dead skin fluffs off pathogens.

Eyes- tears

Repiratory- cilia/mucus-cough/sneeze

Digestive- enzymes destroy (stomach)

*2nd Line of Defense  -  Non specific

Inflammation- infected area red and swollen. fever helps by slowing growth of disese. Blood goes to area. WBC-(pagocytes)  patrol to find disease then engulf and digest pathogens.

*3rd Line of Defense - Specific against disease

Immune system:  wbc-(lymphocytes) specific cells that conquer specific antigens.

Antibodies match up markings of antigens to prepare for destruction.

T-cells:  Lymphocytes that originate in the bone marrow but mature in the Thymus.

Two types: 1) Helper T cells- detect and identify presence by reading markings, antigens, of invaders. Alert B cells and killer T cells. 

2) Killer T cells- target viruses and destroy them. 

B-cells: Lymphocytes that originate and mature in the Bone marrow.

Produce antibodies that bind with the pathogens antigens so the wbc-phagocytes can prey and destroy them. Makes plasma cells that have the antibodies. 

Also makes memory cells to help with immunity for  future detection of the pathogen. It takes longer to produce antibodies to new antigen. 

Targets bacteria. 

Passive Immunity: short term.   antibodies prduced by other source, puts antibodies into our bodies.   

Active Immunity: long lasting.   

body  makes own antibodies to respond to antigen. 

begin soon as antigen introduced- quicker 2nd time around against the pathogen.

*Once body has had the disease, gets immunity so doesn’t get it again. This is due to memory cells. 

*Vaccine- weakened shot of antigen to begin process of antibody production, so memory cells will be available once the diseased pathogen arrives into the system.


* Person doesn’t contract, not an infection

* Person can’t avoid

*  Person’s can’t spread from one to another

* Causes: harmful substances, irritants, unbalanced diet, failed immune syst. and stress

Immune Project Options/Guidelines







W.T. Eich Intermediate