Understanding Your Immune System: Defense Against Disease

Comprehensive practice flashcards covering the lymphatic system, innate vs adaptive immunity, white blood cells, antibodies, pathogen classification (bacteria, viruses, fungi), vaccines, and specific infectious diseases.

What is the lymphatic system and what is its primary role in the body?

A network of vessels and organs throughout the body that serves as a first line of defense against invaders.

What is lymph?

A clear fluid that travels through lymphatic vessels, carries white blood cells, and fights infection.

Which two major lymphatic organs are identified in this anatomical diagram?

Thymus and spleen.

What is innate immunity?

The body's natural, built-in defense system present from birth that responds immediately and identically to all invaders without requiring prior exposure.

What are three innate defense mechanisms that serve as first responders?

The skin (physical barrier), stomach acid (kills harmful organisms before they infect), and inflammation (fights infection and heals damage).

What is adaptive immunity?

A specialized defense system that develops over time, targets specific pathogens encountered previously, and creates memory cells for faster, long-lasting protection.

What are white blood cells and what is their primary duty?

Specialized cells that patrol the bloodstream and lymphatic system to fight infection and disease by destroying pathogens, coordinating immune responses, and cleaning up dead cells.

What is the primary role of neutrophils?

They are the most common type of white blood cell and attack bacteria.

Which two cell types are classified as lymphocytes?

T cells and B cells, which target specific threats.

What role do macrophages play in the immune system?

They are large white blood cells that engulf and destroy pathogens.

What is the main function of dendritic cells?

To alert other immune cells to danger.

What are antibodies and which cells produce them?

Proteins produced by B cells that are designed to recognize, tag, and neutralize specific pathogens or toxins.

How do antibodies recognize and eliminate pathogens?

They bind to pathogens like a lock and key, tagging them for destruction by other immune cells or neutralizing toxins produced by bacteria.

What is the fundamental structural difference between bacteria and viruses regarding survival and reproduction?

Bacteria are single-celled organisms that can survive and reproduce independently, whereas viruses are parasites lacking ribosomes that cannot make proteins on their own and must hijack host cells.

What structural component of bacterial cell walls is targeted by antibiotics?

Peptidoglycan.

Why are antibiotics ineffective against viral infections?

Antibiotics specifically target bacterial components like peptidoglycan cell walls, which viruses lack.

What are the biological characteristics of fungi and how do they obtain nutrition?

Fungi are eukaryotic decomposers and parasites that feed off dead matter and living organisms via absorption.

What are the medical names for ringworm, yeast infections, athlete's foot, and nail fungus?

Ringworm is Tinea corporis, yeast infections are Candidiasis, athlete's foot is Tinea pedis, and nail fungus is Onychomycosis.

How do vaccines train the adaptive immune system?

They expose the body to a weakened or inactive pathogen, triggering B cells to create antibodies and establish immunological memory without causing serious illness.

What is herd immunity?

A form of indirect protection that occurs when enough people in a population are vaccinated to prevent the disease from spreading.

What pathogen causes Rabies, how is it transmitted, and how effective is prompt post-exposure prophylaxis?

It is caused by Rhabdovirus, transmitted through saliva via bites or scratches from infected animals, and post-exposure prophylaxis is nearly $100\%$ effective if administered quickly.

What pathogen causes Ebola Virus Disease and what are its key symptoms?

Filovirus; symptoms include sudden fever, severe weakness, muscle pain, and internal and external bleeding.

What pathogen causes COVID-19 and what are its primary symptoms?

SARS-CoV-2; key symptoms include fever, cough, difficulty breathing, and loss of taste or smell.

What viral strains cause Influenza, and what is the primary preventive measure?

Influenza virus strains A, B, and C; prevented most effectively by an annual flu vaccine.

Which bacterium causes this respiratory infection characterized by a persistent cough lasting more than $3\,\text{weeks}$, chest pain, and coughing up blood?

Mycobacterium tuberculosis (causing Tuberculosis).

What virus causes AIDS, and what class of medications suppresses it?

Human Immunodeficiency Virus (HIV); managed using antiretroviral therapy.

How is Human Papillomavirus (HPV) transmitted and when is the HPV vaccine most effective?

Transmitted through skin-to-skin contact (often sexual); the vaccine is most effective when administered before sexual activity begins.

What virus causes Mononucleosis and what are its key symptoms?

Epstein-Barr Virus; causes severe sore throat, swollen lymph nodes, fever, and extreme fatigue.

What bacterium causes MRSA skin infections and what does MRSA stand for?

Methicillin-Resistant Staphylococcus aureus; a bacterium causing red, swollen, painful skin lesions that may contain pus or drainage.

According to this transmission cycle diagram, which mosquito vector is responsible for transmitting the Dengue virus (Flavivirus)?

Aedes aegypti mosquito.