L18 P1 Pathogens & The Immune System

Flashcards covering key vocabulary and concepts related to pathogens and the immune system.

Pathogen

A pathogen is a tiny living thing, like a germ, that can get inside your body and cause you to get sick. Think of it as a troublemaker that wants to make you feel bad.

Microbiome

Your microbiome is like a community of tiny organisms, mostly bacteria, that live all over your body, both inside and out. Many of these microbes are helpful and keep you healthy.

Immune System

The immune system is your body's defense force. It's a complex network of cells, tissues, and organs that work together to protect you from pathogens. It's like having an army inside you that fights off invaders.

Innate Immunity

Innate immunity is the defense system you're born with. It's a quick and general response that targets common things found on pathogens. Think of it as your body's first responders.

Adaptive Immunity

Adaptive immunity is immunity that develops over time as your body learns to recognize and remember specific pathogens. It's a slower but more precise response. Think of it as your body's special forces.

Barrier Defenses

Barrier defenses are physical and chemical barriers that prevent pathogens from entering your body. These include your skin, mucous membranes, and secretions like tears and saliva. Think of them as the walls and moats of your body's castle.

Phagocytic Cells

Phagocytic cells are immune cells that eat and destroy pathogens. They engulf the pathogens and break them down, clearing them from your body. Think of them as the garbage trucks of your immune system.

Macrophages

Macrophages are large phagocytic cells that can move around the body or stay in one place in tissues. They're like the big eaters of the immune system, engulfing pathogens and dead cells.

Neutrophils

Neutrophils are phagocytic cells that circulate in the blood. They're quickly attracted to signals from injured or infected tissue, where they engulf and destroy pathogens. Think of them as the rapid response team of the immune system.

Natural Killer Cells

Natural killer cells are immune cells that can kill pathogens without engulfing them. They release chemicals that cause the infected cells to die. Think of them as the assassins of the immune system.

Eosinophils

Eosinophils are immune cells that release destructive enzymes to destroy large pathogens like parasitic worms. They're like the heavy artillery of the immune system.

Mast Cells

Mast cells are cells in connective tissue that release histamine, a chemical that causes inflammation and allergies. Think of them as the alarm bells of the immune system.

Dendritic Cells

Dendritic cells are immune cells that communicate with adaptive immune cells. They present antigens to T cells, helping to activate the adaptive immune response. Think of them as the messengers of the immune system.

Inflammation

Inflammation is a response to injury or infection characterized by heat, swelling, redness, and pain. It's a sign that your immune system is working to fight off the threat. Think of it as your body's way of calling for help.

Cytokines

Cytokines are signaling molecules that recruit neutrophils to the injured or infected site. Think of them as chemical messengers that help coordinate the immune response.

Histamine

Histamine is a chemical that causes vasodilation (widening of blood vessels) and increases the permeability of local blood vessels. This helps to bring more immune cells to the site of infection or injury.

Lymph Nodes

Lymph nodes are small, bean-shaped organs that filter lymph fluid. They contain macrophages that engulf pathogens in the lymph, helping to clear them from your body. Think of them as the filtration plants of the immune system.

Toll-Like Receptors (TLRs)

Toll-like receptors are receptors of the innate immune system that detect characteristics common to many pathogens but not found in our own cells. Think of them as the security cameras of the immune system.

Adaptive Response

Adaptive immunity relies on B cells and T cells to recognize and remember specific pathogens. It's a slower but more precise response than innate immunity.

B Cells

B cells are lymphocytes (a type of white blood cell) that mature in the bone marrow. They produce antibodies that help to neutralize pathogens.

T Cells

T cells are lymphocytes that mature in the thymus. They help to kill infected cells and activate other immune cells.

Antigens

Antigens are substances that can trigger a response from a B or T cell. They're like the