bio unit 9

What is a pathogen?

A disease causing agent

What are examples of pathogens?

Viruses bacteria fungi and small animals

What are antigens?

Proteins that identify whether a cell is foreign or part of the body

What are the three outer defenses of the body?

Skin hair and mucus membranes and stomach acid

What is the function of skin?

Acts as a physical barrier

What do hair and mucus membranes do?

Trap pathogens

What does stomach acid do?

Kills most pathogens

What is non specific immunity?

Defense that works the same against all pathogens

What are phagocytes?

White blood cells that engulf foreign objects

What do phagocytes do?

Engulf and destroy pathogens

What are interferons?

Proteins that slow virus replication

How does fever help immunity?

Speeds white blood cell reproduction and slows pathogens

How does inflammation help immunity?

Brings more white blood cells to infected areas

What is specific immunity?

A targeted response against a specific pathogen

When does specific immunity activate?

Several days to a week after infection

What cells are used in specific immunity?

Lymphocytes

What do helper T cells do?

Activate cellular and humoral immunity

What happens first in specific immunity?

A phagocyte engulfs a pathogen and displays its antigen

What happens in cellular immunity?

T cells destroy infected body cells

What do T lymphocytes become?

Killer T cells

What is the purpose of cellular immunity?

To fight viruses

What happens in humoral immunity?

B cells produce antibodies

What do B lymphocytes become?

Plasma cells

What do plasma cells release?

Antibodies

What are antibodies?

Proteins that attach to antigens and destroy pathogens

How do antibodies help phagocytes?

They make pathogens easier to engulf

What are memory cells?

Cells that remember how to destroy a pathogen

Where are memory cells stored?

Lymph nodes

Why are memory cells important?

They provide faster future protection

What is active immunity?

Immunity developed after fighting infection

What is passive immunity?

Temporary immunity from transferred antibodies

Which type of immunity is permanent?

Active immunity

Which type of immunity wears off?

Passive immunity

How does passive immunity happen?

Antibodies are transferred from mother to baby

How do vaccines work?

They expose the body to weakened pathogens to create memory cells

What does HIV infect?

Helper T cells

Why is HIV dangerous?

It weakens the immune system

What is AIDS?

A disease caused by HIV

Why does HIV hurt the immune system so much?

Because helper T cells activate immune responses

What is inflammation caused by?

Histamine release

What does histamine do?

Causes blood vessels to swell and become porous