Lines of Defense Flashcards
(26 cards)
What is the first line of defense in the immune system?
Quick, general, external defense, non-specific, physical and chemical barriers
Physical barriers stop pathogens from entering the body, and chemical barriers kill them.
What role does the skin play in the immune system?
Acts as a barrier between pathogens and body, forming a waterproof barrier
Microorganisms on the skin or pathogens cannot enter unless the skin is broken.
What is the function of cilia in the respiratory system?
Sweep away pathogens in lungs, trachea, and nasal cavity.
What is the purpose of mucus membranes?
Trap/stick pathogens and contain enzymes that break down cell walls.
What is the role of urine flow in the immune system?
Pushes out pathogens from the bladder area.
How does the stomach lining contribute to the immune system?
Contains acid with low pH that corrodes pathogens.
What are ‘friendly bacteria’?
Probiotics that kill/control the growth of pathogens.
What is the second line of defense in the immune system?
Active when pathogens get past the first line, quick and general response to bacteria and some viruses.
What occurs during inflammation?
Chemicals are released when bacteria enter the blood, causing increased blood flow and attracting phagocytes.
What is histamine and its role in the immune response?
Stored in mast cells, it boosts blood flow in the affected area.
What do prostaglandins do?
Hormones created at the site of injury that signal more blood flow and macrophages.
What are macrophages?
A type of phagocyte that moves out of blood vessels to eat up pathogens.
What is phagocytosis?
The process by which phagocytes engulf and destroy pathogens.
What happens if macrophages cannot eat a pathogen?
The complement system is activated.
What is the complement system?
A series of proteins that latch onto pathogens and cause cell lysis.
What are antigens?
Proteins found on the surface of pathogens that trigger an immune response.
What do B cells respond to?
Freely moving antigens in the blood.
What do T cells respond to?
Small fragments of antigens inside infected cells.
What happens when B cells detect a foreign antigen?
They send an alarm and begin making copies.
What are the two categories into which copies of B cells divide?
- Plasma B cells
- Memory B cells.
What is the role of plasma B cells?
To make antibodies.
What do antibodies do?
Bind to specific antigens and help neutralize or deactivate them.
What are Killer T cells (cytotoxic T cells)?
Cells that kill infected body cells.
How do T cells identify infected cells?
By recognizing MHC antigens displaying peptide fragments from pathogens.
