Immune System and Infectious Diseases Study Guide

What is the purpose of the immune system?

To protect the body from pathogens.

What is innate immunity?

A broad, non-specific defense present from birth.

What is adaptive immunity?

A specific, targeted immune response to particular pathogens.

What makes up the first line of defense?

Skin, mucous membranes, expulsions.

Why is skin an effective barrier?

Acidic pH, salt, lysozyme, normal flora.

What is included in the second line of defense?

Interferons, complement, fever, phagocytosis.

What does fever do?

Slows pathogen growth and accelerates immune reactions.

What do helper T cells do?

Activate B cells and cytotoxic T cells.

What does HIV target?

Helper T cells.

What do cytotoxic T cells do?

Kill virus-infected cells via apoptosis.

What is apoptosis?

Programmed cell death.

What do interferons do?

Warn nearby cells of viral infection.

What do complement proteins do?

Cause inflammation and destroy pathogens.

What is the MAC?

Membrane attack complex that punches holes in cells.

What is the goal of phagocytosis?

Engulf and digest pathogens.

What do B cells produce?

Antibodies.

How many antibodies can humans create?

10–20 billion.

What are memory B cells?

Long-lived cells enabling rapid future responses.

What do plasma cells do?

Produce antibodies and die.

What is selective toxicity?

Drug harms bacteria without harming human cells.

What is antibiotic resistance?

Bacteria survive despite antibiotics.

What are the three resistance strategies?

Prevent uptake, break drug down, overproduce target.

What is an opportunistic infection?

Infection exploiting weakened immunity.

Why don't antibiotics treat viruses?

Viruses lack bacterial structures.

What does Penicillin target?

Cell wall synthesis.

What does Vancomycin target?

Cell wall.

What does Polymyxin B target?

Cell membrane.

What does Ciprofloxacin target?

DNA replication.

What does Tetracycline target?

Ribosomes.

What is a prion?

Misfolded infectious protein.

Why can't the immune system detect prions?

They resemble normal proteins.

Why are prions hard to destroy?

They resist heat, chemicals, and immunity.

How do prions replicate?

Convert normal proteins into misfolded forms.

What disease does BSE cause?

Mad Cow Disease.

What is Kuru?

Prion disease linked to cannibalism.

What is Chronic Wasting Disease?

Prion disease in deer.

What is Scrapie?

Sheep prion disease.

What is Jakob disease?

Human prion disease.

What is Ascaris lumbricoides?

A giant intestinal roundworm.

How is Ascaris transmitted?

Fecal–oral ingestion.

What happens after eggs are swallowed?

Larvae steal nutrients.

Is Ascaris common in the U.S.?

No.

What problems can Ascaris cause?

Blockage, malnutrition.

What is Wuchereria bancrofti?

Parasitic worm causing lymphatic disease.

What carries Wuchereria?

Mosquitoes.

What tissue does it infect?

Lymphatic vessels.

What disease can it cause?

Elephantiasis.

Why is it rare in the U.S.?

Mosquito/climate mismatch.

What is Naegleria fowleri?

Brain-eating amoeba.

Where is it found?

Warm stagnant freshwater.

How does infection occur?

Water enters nose, amoeba reaches brain.

How many cases yearly?

5–10.

What is mortality rate?

Over 95%.

When do symptoms appear?

5–10 days.

What are early symptoms?

Loss of smell, fever, headache.

What are late symptoms?

Confusion, seizures, stiff neck.

What is Tinea capitis?

Scalp infection.

What is Tinea barbae?

Beard infection.

What is Tinea cruris?

Jock itch.

What is Tinea corporis?

Body ringworm.

What is Tinea manus?

Hands.

What is Tinea unguium?

Nails.

What is Tinea pedis?

Athlete's foot.

What organism is Candida?

Yeast.

What infections does it cause?

Thrush, yeast infections.

Where does it live?

Normal flora.

What crop does Claviceps infect?

Rye.

What toxin does it produce?

Ergot.

What is the historical link of Claviceps?

Salem Witch Trials.

What disease does Sporothrix cause?

Rose-picker's disease.

How is Sporothrix transmitted?

Thorn punctures.

What disease does Histoplasma cause?

Darling’s disease.

How is Histoplasma transmitted?

Inhalation.

Where is Histoplasma common?

Southwest U.S., Ohio Valley.

What disease does Mucor cause?

Zygomycosis.

Where does Mucor infection begin?

Nose/sinuses.

Who is at risk for Mucor infections?

Elderly, immunocompromised.

What diseases does VZV cause?

Chickenpox and shingles.

When was the VZV vaccine made?

1995.

How is VZV spread?

Respiratory droplets.

What percent of people get shingles?

15–20%.

Why should you avoid aspirin during chickenpox?

Reye’s syndrome.

What causes shingles recurrence?

Dormant VZV reactivation.

When was smallpox eradicated?

1980.

Why is smallpox still a concern?

Bioterror potential.

How is smallpox transmitted?

Human-to-human.

What are the symptoms of smallpox?

Fever, rash, lesions.

What is the mortality rate of smallpox?

Up to 40%.

How is Ebola transmitted?

Blood/body fluids.