2140 Immune System

When does the immune system begin developing?

4-6 weeks of development.

What is immunity?

Resistance to diseases caused by pathogens.

What are the five types of pathogens?

Bacteria, viruses, fungi, protozoa, and parasitic worms.

What is a pathogen?

A whole organism that can cause disease.

What are antigens?

Substances that elicit an immune response.

What is Salmonella commonly carried by?

Chickens.

How quickly does the innate immune system respond?

About 12 hours.

What cells and components are part of innate immunity?

Macrophages, neutrophils, NK cells, dendritic cells, epithelial barriers, and complement.

What are the three lines of defense?

1. Surface barriers 2. Internal defenses 3. Adaptive immune system.

What is the first line of defense?

Surface barriers.

What is the second line of defense?

Internal defenses involving cells and chemicals.

What is the third line of defense?

Adaptive immune system.

What is the adaptive immune system?

A specific immune response that targets particular antigens.

What are the two types of adaptive immunity?

Humoral immunity (B cells) and cellular immunity (T cells).

What is an antigen-presenting cell (APC)?

A cell that picks up antigen information and presents it to the adaptive immune system.

What is the first line of defense made up of?

Physical barriers and protective chemicals.

What are examples of physical barriers?

Skin and mucous membranes.

What is keratin?

A protective substance in the skin that resists weak acids and bases, bacterial enzymes, and toxins.

What do mucous membranes do?

Provide barriers at openings of the body.

Where are mucous membranes found?

Digestive, respiratory, and reproductive systems.

What are protective chemicals?

Chemicals that inhibit or destroy microorganisms.

What does acidity do?

Helps prevent microorganism growth.

Where is lysozyme found?

Saliva.

What does lysozyme do?

Inhibits the growth of bacteria (bacteriostatic).

What is mucin?

A substance that combines with water to form mucus.

What does mucus do?

Traps bacteria in the respiratory and digestive systems.

What are defensins?

Peptides in surface barriers that prevent bacteria from spreading.

What are lipids and dermcidin?

Substances in tears and sweat that are toxic to bacteria.

What is the second line of defense?

Internal defenses made up of cells and chemicals.

What triggers inflammation?

Tissue injury or infection.

What are three purposes of inflammation?

Prevent the spread of damaging agents, dispose of cellular debris and pathogens, and prepare tissues for repair.

What does PRISH stand for?

Pain, Redness, Impairment, Swelling, Heat.

What are the cardinal signs of acute inflammation?

Pain, redness, impairment, swelling, and heat.

What is the difference between heat and fever?

Heat is a localized increase in temperature; fever is a systemic increase in body temperature.

What are phagocytes?

Cells that engulf and destroy disease-causing agents.

What is phagocytosis?

The ingestion and elimination of disease-causing agents.

What is the first step of phagocyte movement?

Leukocytosis: signals bring cells to the site of injury.

What is the second step of phagocyte movement?

Margination: rolling and adherence to blood vessel walls.

What is rolling?

Phagocytes roll along blood vessels and attach to proteins.

What is the third step of phagocyte movement?

Transmigration: phagocytes move from the blood vessel into the tissue.

What is the fourth step of phagocyte movement?

Chemotaxis: chemicals attract cells to the site of injury.

What is the fifth step of phagocyte movement?

Phagocytosis: ingestion and elimination of disease-causing agents.

What is the sixth step of phagocyte movement?

Apoptosis: programmed cell death.

What are the four steps of phagocytosis?

1. Pseudopod formation 2. Phagosome formation 3. Phagolysosome formation 4. Digestion and exocytosis.

What is pseudopod formation?

Formation of extensions that surround and engulf a particle.

What is a phagosome?

A specialized organelle that encapsulates the engulfed particle.

What is a lysosome?

An acid-filled organelle containing enzymes that break down particles.

What is a phagolysosome?

A structure formed when a phagosome combines with a lysosome.

What happens after a phagolysosome forms?

Digestion and exocytosis.

What is apoptosis?

Programmed cell death that packages cellular contents before the cell dies without causing an inflammatory response.

What is necrosis?

Cellular death associated with tissue damage and inflammation.

What is the difference between apoptosis and necrosis?

Apoptosis is controlled and quiet; necrosis is damaging and can cause inflammation.

What do natural killer (NK) cells target?

Cancer cells and virus-infected cells.

What do NK cells look for?

Cells that lack normal self-receptors.

What are granulocytes?

Cells that contain granules.

What do granulocytes contain?

Histamines, enzymes, and heparin.

What are the three antimicrobial protein pathways?

Antimicrobial proteins, complement proteins, and interferons.

What do antimicrobial proteins do?

Inhibit the growth of bacteria.

What do complement proteins do?

Help set up the phagocytic process in the immune system.

What are interferons?

Virus-specific proteins that help prevent the spread of viruses.

When are interferons produced?

When a host cell becomes infected with a virus.

How do interferons protect nearby cells?

They signal cells to produce antiviral proteins that prevent viral replication.

What is a fever?

A systemic response involving elevated body temperature.

What cells secrete pyrogens?

Macrophages.

What is a pyrogen?

A substance that causes fever.

What are two benefits of a moderate fever?

Increases metabolic rate and causes the liver and spleen to hold onto iron and zinc.

What is adaptive immunity?

The third line of defense that provides a specific immune response.

What are three functions of adaptive immunity?

Protects against infectious agents and abnormal body cells, amplifies inflammation, and activates complement pathways.

What are three characteristics of adaptive immunity?

Specific, systemic, and has memory.

What are the two arms of adaptive immunity?

Humoral immunity (B cells) and cellular immunity (T cells).

What are lymphocytes?

Immature immune cells that develop and mature into functional immune cells.

Where do lymphocytes develop?

Bone marrow and bursa.

What is immunocompetence?

The ability to recognize, find, and bind to antigens.

What is self-tolerance?

Being unresponsive to the body's own antigens.

What are the two main types of lymphocytes?

B lymphocytes and T lymphocytes.

What do B lymphocytes produce?

Plasma cells that produce antibodies.

What are plasma cells?

Cells that produce antibodies.

What is proliferation?

The multiplication of cells.

What do antibodies do?

Bind to and inactivate or tag antigens.

What is an antigen-antibody complex?

A structure formed when an antibody binds to an antigen.

What are the four main antibody defense mechanisms?

Precipitation, complement fixation, agglutination, and neutralization (PLAN).

What is precipitation?

Antibodies bind soluble antigens and pull them out of the area.

What type of antigens are involved in precipitation?

Soluble antigens.

What is complement fixation?

Antibodies bind to a cell surface and recruit proteins that form pores and cause cell lysis.

What does complement fixation stimulate?

Inflammation and phagocytosis.

What is agglutination?

Antibodies pull whole cells together to form a large mass.

What happens after agglutination?

Phagocytosis.

What is neutralization?

Antibodies mask toxic or dangerous areas of an antigen.

What happens after neutralization?

Phagocytosis can remove the tagged antigen.

What does PLAN stand for?

Precipitation, Lysis (complement fixation), Agglutination, and Neutralization.

What is humoral immunity?

Immunity involving B cells and antibodies.

What happens during the primary immune response?

The body encounters an antigen for the first time and begins producing antibodies.

What happens during the secondary immune response?

The body encounters the same antigen again and responds faster because of memory cells.

What is active immunity?

The body produces its own antibodies.

What are the two types of active immunity?

Naturally acquired and artificially acquired.

How is naturally acquired active immunity gained?

Through infection and contact with pathogens.

How is artificially acquired active immunity gained?

Through vaccines.

What are vaccines made from according to the notes?

Dead or attenuated (modified live) pathogens.

What is passive immunity?

Antibodies are provided to the body.

What are the two types of passive immunity?

Naturally acquired and artificially acquired.