Biology - Immune System

define pathogen

disease causing agent

define antigen

a marker that triggers an immune response

types of pathogens

virus, bacteria, fungi, protista, parasites, prion

types of antigens

Self and non self

Explain the role of self cells in the immune system

The body’s own molecules/cells that are recognized as belonging to the organism. MHC markers help identify cells as “self,” so the immune system normally does not attack them.

Why is recognizing self cells important

So immune cells don’t damage the body’s tissue

explain the role of non self cells in the immune system

Foreign molecules from pathogens or other outside sources. These trigger an immune response.

Explain how transplanted organs can elicit an immune response in the recipient and perhaps lead to organ rejection

Because the recipient’s immune system recognizes the donor organ’s cells as non-self, which can trigger an immune response to the new organ

Explain how recipients of organ transplants can prevent organ rejection

immunosuppressants so their immune system doesn’t attack the new organ

Define first line of defense

The body’s initial, nonspecific barriers that prevent pathogens from entering the body

Define Innate Immunity

Non specific, faster response that we have at birth and fights all non self markers, includes first and second line of defense

List the types of physical barriers that pose as the First Line of Defense

Skin, mucous, tears, sweat, stomach acid, cilia

List the types of chemical barriers that serve as part of the First Line of Defense

Lysozyme in tears and saliva, Acidic secretions of the skin, stomach acid

Explain why the First Line of Defense is considered to be non-specific

It only differentiates between self and non self instead of targeting one specific invader

Explain why the First Line of Defense is considered to be Innate

it is present from birth and does not require prior exposure to a pathogen to function

Explain how a physical barrier can serve to protect an individual from a pathogen

It prevents the pathogen from entering the body in the first place

Explain how a chemical barrier can serve to protect an individual from a pathogen.

it creates conditions that damage/destroy microbes or prevent them from growing

example of chemical barrier protecting an individual from a pathogen

stomach acid and lysozyme in tears and saliva