Immunology Overview Quiz
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Questions and Answers

What type of immunity is present at birth and provides nonspecific resistance to infection?

  • Acquired immunity
  • Innate immunity (correct)
  • Passive immunity
  • Adaptive immunity

Which line of defense includes protective cells and fluids such as inflammation and phagocytosis?

  • First line of defense
  • Second line of defense (correct)
  • Third line of defense
  • None of the above

How do the lines of defense in the immune system interact?

  • They are strictly compartmentalized with no overlap
  • They overlap and are redundant in some effects (correct)
  • They only activate sequentially, one after the other
  • They function in isolation from one another

What is the main function of the third line of defense in the immune system?

<p>To identify pathogens and create memory cells (C)</p> Signup and view all the answers

Which of the following is NOT a category of the first line of defense?

<p>Cell-mediated immunity (D)</p> Signup and view all the answers

What is the primary role of white blood cells?

<p>To recognize and differentiate foreign materials (A)</p> Signup and view all the answers

What are pathogen-associated patterns (PAMPs)?

<p>Shared molecules by microorganisms (A)</p> Signup and view all the answers

Which body compartment is NOT associated with immune function?

<p>Digestive system (D)</p> Signup and view all the answers

What is the significance of pathogen recognition receptors (PRRs) on white blood cells?

<p>They identify and bind to PAMPs (B)</p> Signup and view all the answers

How does the immune system ensure effective responsiveness?

<p>Through constant communication between fluid compartments (C)</p> Signup and view all the answers

What characterizes the third line of defense in the immune system?

<p>Involvement of B and T lymphocytes and antibodies (A)</p> Signup and view all the answers

Which of the following best describes the difference between innate and adaptive immunity?

<p>Adaptive immunity requires prior exposure to pathogens; innate does not. (B)</p> Signup and view all the answers

Which of the following lists the primary roles of a healthy immune system?

<p>To eliminate pathogens, identify self from non-self, and develop memory (C)</p> Signup and view all the answers

What is the role of phagocytes in the immune system?

<p>To engulf and digest pathogens (C)</p> Signup and view all the answers

Which statement accurately describes the lymphatic system?

<p>It circulates lymph and aids in the immune response. (C)</p> Signup and view all the answers

What initiates the assembly of the membrane attack complex (MAC)?

<p>C5b (D)</p> Signup and view all the answers

How many C9 units can ring the central core of the membrane attack complex?

<p>15 (B)</p> Signup and view all the answers

Which of the following describes the action of the membrane attack complex?

<p>Causes lysis of microbial cell membranes (D)</p> Signup and view all the answers

Which component acts to convert C5 into C5b?

<p>C3b (C)</p> Signup and view all the answers

What is a role of the products C3a and C5a in immune response?

<p>Stimulate mast cell degranulation (A)</p> Signup and view all the answers

What constitutes the first line of defense in host defenses?

<p>Chemical barriers (A)</p> Signup and view all the answers

What triggers the second line of defense in the immune response?

<p>Presence of infectious agents (B)</p> Signup and view all the answers

Which component aggregates with C5b to form the membrane attack complex?

<p>C6 (B)</p> Signup and view all the answers

What are the primary functions of phagocytes?

<p>To survey tissue compartments and ingest foreign materials. (A)</p> Signup and view all the answers

Which phagocyte is specifically attracted to parasitic infections?

<p>Eosinophils (B)</p> Signup and view all the answers

What is the key role of Toll-like receptors (TLRs) in macrophages?

<p>To detect foreign molecules and signal for immune response. (B)</p> Signup and view all the answers

What process occurs when a phagocyte engulfs a pathogen?

<p>Phagosome formation (A)</p> Signup and view all the answers

What is caused by the respiratory burst during phagocytosis?

<p>Generation of antimicrobial substances. (A)</p> Signup and view all the answers

Which type of interferon is produced specifically by T cells?

<p>Interferon gamma (B)</p> Signup and view all the answers

What is a function of the complement system in the immune response?

<p>Destroys bacteria and viruses through a cascade reaction. (B)</p> Signup and view all the answers

In the complement cascade, what does opsonization refer to?

<p>The process of marking pathogens for phagocytosis. (A)</p> Signup and view all the answers

What happens to monocytes after leaving the bloodstream?

<p>They transform into macrophages or dendritic cells. (D)</p> Signup and view all the answers

How do erythrocytes contribute to the immune response?

<p>By collecting pathogenic cell-free DNA. (A)</p> Signup and view all the answers

What primarily characterizes erythrocytes?

<p>They are simple biconcave sacs of hemoglobin. (A)</p> Signup and view all the answers

What is the primary function of the lymphatic system?

<p>To return extracellular fluid to the circulatory system. (D)</p> Signup and view all the answers

Which of the following best describes lymph?

<p>A plasma-like liquid with water and dissolved salts. (C)</p> Signup and view all the answers

What distinguishes primary lymphoid organs from secondary lymphoid organs?

<p>Primary organs include the thymus and bone marrow, secondary include lymph nodes. (D)</p> Signup and view all the answers

What role does inflammation play in host defenses?

<p>It helps to restore homeostasis and clear away invading microbes. (C)</p> Signup and view all the answers

What is the correct sequence of events at the initial stage of an inflammatory response?

<p>Vasoconstriction, blood clots, chemokine release. (D)</p> Signup and view all the answers

Which of the following is NOT a component of an inflammatory response?

<p>Cooling of the tissue. (C)</p> Signup and view all the answers

What is the primary role of the spleen in the lymphatic system?

<p>Filtering circulating blood to remove worn out red blood cells. (D)</p> Signup and view all the answers

Lymphatic vessels are unique because they:

<p>Carry lymph in a unidirectional flow toward the heart. (B)</p> Signup and view all the answers

What primarily occurs in the bone marrow related to lymphocytes?

<p>Origin and maturation of B-cells. (B)</p> Signup and view all the answers

What is the main focus of the first line of defense in the immune system?

<p>Blocking invasion at the portal of entry (A)</p> Signup and view all the answers

What type of immunity requires previous exposure to a foreign substance?

<p>Acquired immunity (B)</p> Signup and view all the answers

Which of the following best describes the role of chemical defenses in the body's immune response?

<p>They provide a nonspecific barrier to pathogens. (D)</p> Signup and view all the answers

What is the significance of the overlapping nature of the immune defense mechanisms?

<p>To ensure redundancy in protection against infections. (A)</p> Signup and view all the answers

Which line of defense is primarily associated with nonspecific cellular responses to pathogens?

<p>Second line of defense (B)</p> Signup and view all the answers

What are the common signs and symptoms of secondary stage syphilis?

<p>Skin rash and muscle aches (B)</p> Signup and view all the answers

Which internal organs can be affected in the late stages of syphilis?

<p>Brain and heart (B)</p> Signup and view all the answers

When does the latent stage of syphilis begin?

<p>When secondary symptoms disappear (A)</p> Signup and view all the answers

Which of the following is NOT a symptom of secondary stage syphilis?

<p>Severe joint pain (C)</p> Signup and view all the answers

What might happen during the late stages of untreated syphilis?

<p>Damage to the internal organs (C)</p> Signup and view all the answers

What is a characteristic feature of the third line of defense in the immune system?

<p>It develops memory for specific pathogens. (A)</p> Signup and view all the answers

Which type of lymphocyte is primarily involved in the adaptive immune response?

<p>B lymphocytes (C)</p> Signup and view all the answers

How are specific host defenses developed in the immune system?

<p>By the action of specialized white blood cells. (A)</p> Signup and view all the answers

Which of the following best describes the function of antibodies in the immune system?

<p>They mark pathogens for destruction by other immune cells. (D)</p> Signup and view all the answers

What is the role of memory cells in the immune response?

<p>They remember past infections, enabling faster responses. (D)</p> Signup and view all the answers

What organism is associated with the disease syphilis?

<p>Treponema pallidum (C)</p> Signup and view all the answers

What is the primary mode of transmission for syphilis?

<p>Sexual contact or saliva (D)</p> Signup and view all the answers

Which demographic saw an increase in syphilis cases starting in 2000?

<p>Men who have sex with men (MSM) (B)</p> Signup and view all the answers

What was the age group with the highest rates of primary and secondary syphilis in 2011?

<p>Men aged 20-29 (C)</p> Signup and view all the answers

How many cases of gonorrhea were reported in 2015?

<p>395,216 (D)</p> Signup and view all the answers

What is the primary reservoir for Treponema pallidum?

<p>Humans (A)</p> Signup and view all the answers

What spirochete structure allows Treponema pallidum to be motile?

<p>Axial filament (A)</p> Signup and view all the answers

How many cases of syphilis were reported in 2020?

<p>133,945 (C)</p> Signup and view all the answers

What is the role of C5b in the complement cascade?

<p>It initiates the polymerization of membrane attack complexes. (A)</p> Signup and view all the answers

What do C3a and C5a contribute to the immune response?

<p>They stimulate mast cell degranulation and enhance chemotaxis. (B)</p> Signup and view all the answers

What occurs during vascular reactions in the inflammatory response?

<p>Increased vascular permeability and fluid leakage (B)</p> Signup and view all the answers

Which of the following describes the role of diapedesis in the immune response?

<p>Migration of cells towards infection due to chemical signals (A)</p> Signup and view all the answers

Which component is the final one to bind during the formation of the membrane attack complex?

<p>C9 (C)</p> Signup and view all the answers

What is the primary mechanism by which fever enhances the immune response?

<p>It increases metabolic rate and stimulates protective processes. (D)</p> Signup and view all the answers

How does the membrane attack complex damage target cells?

<p>By creating pores in the cell membrane. (A)</p> Signup and view all the answers

Which of the following describes the action of the complement in the second line of defense?

<p>It enhances the inflammatory response and opsonization. (B)</p> Signup and view all the answers

Which statement accurately describes the function of chemical mediators in inflammation?

<p>They initiate the clotting process and trap pathogens. (A)</p> Signup and view all the answers

What characterizes edema during the inflammatory response?

<p>Collection of fluid, leading to swelling (D)</p> Signup and view all the answers

What characterizes the first line of defense in host defenses?

<p>It primarily consists of anatomical and physiological barriers. (C)</p> Signup and view all the answers

Which type of pyrogens is produced by infectious agents that lead to fever?

<p>Exogenous pyrogens (A)</p> Signup and view all the answers

During the polymerization phase in the complement cascade, which components aggregate with C5b?

<p>C6, C7, C8 (C)</p> Signup and view all the answers

What is the main purpose of pus formation during inflammation?

<p>To trap and eliminate bacteria and dead cells (D)</p> Signup and view all the answers

What is the primary consequence of the complement cascade's activation?

<p>Lysis of target cell membranes. (A)</p> Signup and view all the answers

What initiates the immune response and repair of injury during the resolution phase of inflammation?

<p>Migration of macrophages, lymphocytes, and fibroblasts (A)</p> Signup and view all the answers

Flashcards

Innate immunity

Nonspecific defense mechanisms present at birth.

Adaptive immunity

Specific, acquired immunity developed after exposure to a foreign substance.

First line of defense

Barriers that prevent pathogen entry at the portal of entry; nonspecific.

Second line of defense

Protective cells, fluids, inflammation, and phagocytosis; nonspecific.

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Third line of defense

Acquired immunity using antibodies and memory cells; specific.

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White blood cells (leukocytes)

Cells that recognize and differentiate foreign material from normal cells in the body.

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Nonself

Foreign material that is recognized by white blood cells.

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Pathogen-associated patterns (PAMPs)

Molecules found on microorganisms that are recognized by the immune system.

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Pathogen recognition receptors (PRRs)

Receptors on white blood cells that recognize PAMPs.

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Immune System

A complex network of cells and fluids throughout the body that helps fight off harmful substances.

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Acquired immunity

The body's ability to recognize and destroy specific pathogens after previous exposure.

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Immune system's specific features

B and T lymphocytes, antibodies, and cytotoxicity are functions for specific pathogen targeting and memory for future encounters.

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Lymphocytes (B and T)

Specialized white blood cells crucial for adaptive immunity, including antibody production and targeted cell destruction.

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Erythrocytes

Red blood cells that develop from bone marrow, lose their nucleus, and contain hemoglobin.

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Platelets

Blood components not whole cells, crucial for blood clotting.

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Lymphatic System

Auxiliary system returning extracellular fluid to the circulatory system and responding to foreign material.

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Lymph

Plasma-like liquid carrying blood components, cellular debris, and infectious agents.

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Lymphatic Vessels

Capillaries that permeate most of the body, returning lymph to circulation.

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Primary Lymphoid Organs

Sites where lymphocytes originate or mature (thymus & bone marrow).

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Secondary Lymphoid Organs

Sites where immune responses occur (lymph nodes, spleen, MALT, GALT).

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Inflammation

A reaction to tissue trauma, seeking to restore homeostasis and clear infection.

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Lymphocytes

Immune cells, part of the immune response.

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Spleen

An organ which filters the blood and removes old red blood cells.

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Complement Cascade Action on C5

C3b acts on C5, converting it to C5b, which initiates membrane attack complex (MAC) formation.

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Membrane Attack Complex (MAC) Formation

C5b recruits C6, C7, and C8, creating a surface for C9 binding. Multiple C9 molecules form a ring, creating a pore in the target cell membrane.

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MAC Function

MACs create holes in cell membranes, leading to cell lysis and death for some bacteria and certain eukaryotic cells.

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C3a and C5a Inflammatory Functions

These complement components stimulate mast cell degranulation and attract white blood cells, enhancing the inflammatory response.

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Inflammatory Response

A cellular and chemical response that isolates and eliminates pathogens from the body.

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Phagocytes

Immune cells that engulf and destroy pathogens.

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Phagocytes (types)

Neutrophils, eosinophils, and macrophages are types of phagocytes, each with specific roles in defense mechanisms.

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Neutrophils

General-purpose phagocytes that react quickly to bacteria and damaged tissue.

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Macrophages

Specialized phagocytes derived from monocytes, they clean up foreign substances and prepare them for immune response.

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Toll-like receptors (TLRs)

Protein receptors on macrophage membranes that detect foreign molecules and trigger an immune response.

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Phagolysosome

The combined structure formed when lysosomes (containing digestive enzymes) fuse with a phagosome (containing engulfed material).

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Complement System

A group of proteins in the blood that work together to kill pathogens, enhance phagocytosis, and promote inflammation.

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Interferons

Small proteins produced by certain immune cells in response to viruses, that block viral replication.

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Membrane Attack Complex (MAC)

A component of the complement system that forms pores in the membranes of target cells, causing cell lysis.

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Opsonization

Coating of a pathogen with proteins to enhance phagocytosis.

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How do the lines of defense work together?

The lines of defense don't work in isolation. They overlap and complement each other, creating a robust defense system. For example, inflammation (second line) can be triggered by a breach in the physical barriers (first line).

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B and T lymphocytes

Specialized white blood cells responsible for recognizing and attacking specific pathogens. B cells produce antibodies, while T cells directly destroy infected cells.

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Cytotoxicity

The ability of certain immune cells, particularly T cells, to directly kill infected cells.

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Memory in Immunity

The ability of the adaptive immune system to remember past encounters with pathogens, allowing for a faster and more effective response upon re-exposure.

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Secondary Syphilis

The second stage of syphilis, characterized by a skin rash and mucous membrane lesions that are not itchy. These lesions can appear as the chancre is healing or several weeks later. The rash often presents as rough, red or reddish brown (copper) spots, especially on palms and soles, but may be faint and go unnoticed. Other symptoms include fever, swollen lymph glands, sore throat, patchy hair loss, headaches, weight loss, muscle aches, and fatigue.

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Late Stage Syphilis

The final stage of syphilis, marked by severe damage to internal organs, including the brain, nerves, eyes, heart, blood vessels, liver, bones, and joints. This can lead to serious complications like difficulty coordinating muscle movements, paralysis, numbness, gradual blindness, and dementia. In some cases, late-stage syphilis can be fatal.

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Chancre

A painless, firm, round, red, or reddish-brown sore that is the first sign of syphilis. It appears at the site of infection, usually within 10-90 days after exposure. It typically heals without treatment but can be highly contagious.

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Rash

Characterized by a skin rash that is not itchy, which often appears as rough, red or reddish brown (copper) spots, especially on the palms and soles of the feet.

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Gumma

A rubbery, painless, slow-growing, and destructive lesion that can appear on the skin, bones, and internal organs during the late stage of syphilis. It is usually present in those who have not received treatment.

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Vascular Reactions

Blood vessels near the injury dilate, increasing blood flow and permeability, leading to fluid leakage and exudate formation.

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Pus formation

Accumulation of dead white blood cells, bacteria, and tissue debris at the site of infection.

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Diapedesis

The movement of white blood cells from blood vessels into tissues.

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Chemotaxis

The movement of cells, especially white blood cells, towards chemical signals at the site of injury or infection.

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Fever

An increase in core body temperature, usually due to infection or inflammation.

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Pyrogens

Substances that induce fever by resetting the body's temperature control center.

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Benefits of fever

Fever can inhibit the growth of pathogens, increase immune responses, and promote tissue repair.

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Treponema pallidum

A type of spirochete bacteria that causes syphilis. It's known for its unique shape and movement due to axial filaments.

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Syphilis transmission

Syphilis is primarily spread through sexual contact or contact with infected saliva, leading to a range of symptoms in different stages.

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Syphilis in the 1990s

During the 1990s, syphilis cases were predominantly found in heterosexual men and women belonging to racial and ethnic minority groups.

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Syphilis shift in the 2000s

Starting in the 2000s, syphilis cases began to increase among men who have sex with men (MSM), indicating a shift in transmission patterns.

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Syphilis age groups

In the early 2000s, syphilis cases peaked among men aged 30-39, but by 2011, the peak shifted to men aged 20-29, suggesting a younger demographic affected.

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MSM and syphilis

Men who have sex with men (MSM) have become a significant group affected by syphilis, with MSM accounting for a large percentage of cases in 2011.

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Syphilis reservoirs

Humans are the only known reservoirs for Treponema pallidum, meaning the bacteria only lives and spreads among humans.

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Syphilis statistics

In 2020, over 133,000 cases of syphilis were reported in the US. This indicates a significant public health concern.

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What starts the MAC assembly?

C5b, formed from C5 by the action of C3b, binds to the membrane and initiates the formation of the membrane attack complex (MAC).

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What molecules join C5b in the MAC?

C6, C7, and C8 sequentially bind to C5b, forming a complex embedded in the membrane.

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What is the role of C9 in the MAC?

Multiple C9 units bind to the C5b-C6-C7-C8 complex, forming a ring structure that creates a pore in the target cell membrane.

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What is the function of the MAC?

The MAC creates holes in the cell membrane, leading to lysis and death of eukaryotic cells and certain bacteria.

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What are the inflammatory effects of C3a and C5a?

C3a and C5a stimulate mast cell degranulation, enhance white blood cell chemotaxis, and act as inflammatory mediators.

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What is the complement system?

A group of proteins in the blood that work together to kill pathogens, enhance phagocytosis, and promote inflammation.

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What is the first line of defense?

The first line of defense consists of physical, chemical, and genetic barriers that prevent pathogens from entering the body.

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What is the second line of defense?

The second line of defense involves cellular (e.g., phagocytes) and chemical (e.g., inflammation) mechanisms that act quickly when pathogens breach the first line of defense.

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Study Notes

Host Defenses and Innate Immunities

  • Innate, natural defenses are present at birth and provide nonspecific resistance to infection
  • Adaptive immunities are specific and must be acquired
  • The body has multiple lines of defense against pathogens
  • The first line of defense is any barrier that blocks invasion at the portal of entry; these are nonspecific
  • The second line of defense are protective cells and fluids, including inflammation and phagocytosis; these are nonspecific
  • The third line of defense acquired with exposure to foreign substance; produces protective antibodies and creates memory cells; these are specific defenses

Overview of Host Defense Mechanisms

  • Host defenses consist of multiple barriers, cells, and chemicals to protect against pathogens (disease-causing agents)
  • A table outlines the lines of defense, indicating whether they are innate or acquired, and the specific or nonspecific nature of their action
  • The first line of defense comprises physical and chemical barriers, as well as genetic resistance
  • The second line of defense utilizes innate responses like inflammation and phagocytosis
  • The third line of defense is adaptive immunity, involving lymphocytes, antibodies, and memory

Types of Host Defenses

  • Physical or anatomical barriers are the body's first line of defense (e.g., skin, mucous membranes, tears, saliva, sweat, acid, low pH).
  • Chemical defenses are also part of the first line of defense and include secretions like sebaceous secretions, antimicrobial secretions, lysozyme, defensins, lactic acid, and acidic pH, digestive enzymes, tears, saliva.
  • Genetic barriers involve inherited factors that provide resistance to certain pathogens

Genetic Defenses

  • Some hosts are genetically resistant to diseases of others
  • Viruses have high specificity for host receptors
  • Genetic differences in susceptibility exist for various pathogens within species
  • Humans with the sickle-cell anemia gene are resistant to malaria

Immunology

  • Immunology is the study of the body's second and third lines of defense
  • Primary functions of a healthy immune system: surveillance, recognition and differentiation of normal versus foreign substances, attack against and destruction of foreign entities.

White Blood Cells

  • White blood cells (leukocytes) have the job of recognizing and differentiating from foreign material (nonself) versus normal body material (self)

PAMPs and PRRs

  • Pathogen-associated molecular patterns (PAMPs) are molecules shared among microorganisms
  • Pathogen recognition receptors (PRRs) are receptors on white blood cells (WBCs) that recognize PAMPs

Body Compartments and Immune Function

  • Body compartments participating in immune function include the reticuloendothelial system, extracellular fluid, bloodstream, and lymphatic system
  • Activities in one fluid compartment must communicate with other compartments for effective immunity

Reticuloendothelial System (RES)

  • The RES is a network of connective tissue that interconnects other cells and meshes with the connective tissue surrounding organs
  • The RES contains phagocytic cells, particularly macrophages, which are ready to attack and ingest microbes that have bypassed the first line of defense

Blood

  • Whole blood consists of plasma (liquid portion) and formed elements (blood cells)
  • Serum is the liquid portion of blood after a clot is formed, minus clotting factors
  • Plasma is primarily water with proteins, globulins, clotting factors, hormones, chemicals, and gases

Blood Cells

  • Hemopoiesis is the production of blood cells from stem cells
  • Primary cell lines include platelets, red blood cells, and leukocytes (white blood cells)
  • Granulocytes have lobed nuclei, while Agranulocytes have unlobed, rounded nuclei

Granulocytes

  • Neutrophils (55-90% of WBCs) are phagocytes, reacting to bacteria and damaged tissue
  • Eosinophils (1-3% of WBCs) destroy eukaryotic pathogens and are involved in allergy
  • Basophils (0.5% of WBCs) release chemical mediators in inflammatory events and allergy
  • Mast cells are nonmotile elements found in connective tissue, involved in inflammatory responses, allergies, and anaphylaxis

Agranulocytes

  • Lymphocytes (20-35% of WBCs) are involved in specific immunity (B cells, humoral, and T cells, cell-mediated)
  • Monocytes (3-7% of WBCs) mature into macrophages and dendritic cells, which are phagocytic cells
  • Macrophages are responsible for final differentiation from monocytes after leaving the circulation system, engulfing foreign materials
  • Dendritic cells trap pathogens and participate in immune reactions

Syphilis

  • The causative agent is Treponema pallidum, a spirochete
  • Syphilis has three stages: primary, secondary, and late/latent
  • Primary stage involves a chancre sore at the infection site.
  • Secondary stage includes a skin rash and other symptoms, potentially followed by a latent stage with no symptoms.
  • Late syphilis can cause significant organ damage, including the brain, nerves, eyes, heart, blood vessels, liver, bones, and joints; it can also result in difficulty coordinating muscles, paralysis, numbness, blindness, and potentially even death.
  • Congenital syphilis can affect newborns, leading to deformed bones, severe anemia, enlarged liver and spleen, jaundice, brain/nerve problems, blindness, deafness, meningitis, or skin rashes
  • Prevention includes safe sexual practices and treatment when diagnosed.

Lymphatic System

  • The lymphatic system provides an auxiliary route for returning extracellular fluid to the circulatory system.
  • It serves as a drain-off system for the inflammatory response.
  • The lymphatic system also renders surveillance, recognition, and protection against foreign material.

Lymphatic Fluid (Lymph)

  • Lymph is a plasma-like fluid carried by lymphatic circulation
  • Formed when blood components leave the blood vessels and enter extracellular spaces
  • Its composition includes water, dissolved salts, and proteins (2–5%)
  • Transports white blood cells, fats, cellular debris, and infectious agents

Lymphatic Vessels

  • Lymphatic capillaries permeate all body parts except the CNS, bone, placenta, and thymus.
  • Thin walls allow for easy permeation by extracellular fluid
  • Contraction of skeletal muscles moves fluid within lymphatic vessels through skeletal muscles.
  • Lymph flow is unidirectional, toward the heart, and eventually returns to the bloodstream.

Lymphoid Organs and Tissues

  • Primary lymphoid organs: Thymus (T cell maturation) and bone marrow (B cell maturation).
  • Secondary lymphoid organs/tissues: Lymph nodes, spleen, MALT, GALT are circulatory-based locations where encounter with microbes happens

Inflammation

  • Inflammation is a response to tissue injury, aiming to restore homeostasis.
  • It involves redness, warmth, swelling (edema), and pain (dolor).
  • Inflammatory mediators are released in response to chemical mediators.
  • Blood vessels dilate and leak fluid, attracting white blood cells (WBCs) including phagocytes.

Phagocytosis

  • Phagocytosis is a key component of the second line of defense
  • Phagocytes: survey tissues to discover microbes or damaged cells.
  • Ingest and eliminate these materials
  • Extract immunogenic information from foreign matter.
  • Major types: Neutrophils, eosinophils, and macrophages. Neutrophils typically react first, followed by other phagocytes.

Interferon

  • Interferon is a small protein produced by certain WBCs and tissue cells in response to viruses, RNA, immune products, and antigens.
  • Three major types: IFN alpha, IFN beta, and IFN gamma, produced by different cells (lymphocytes, macrophages, fibroblasts, and epithelial cells).
  • All three IFN types bind to cell surfaces and stimulate expression of antiviral proteins, reducing cancer gene expression.
  • IFN alpha and beta stimulate phagocytes, and IFN gamma acts as an immune regulator of macrophages and T and B cells.

Complement

  • Complement consists of at least 30 blood proteins working together to eliminate bacteria and viruses by lysis and opsonization
  • Complement proteins are activated by cleavage.
  • Three features: Membrane attack complex (MAC), opsonization, Recruitment of inflammatory mediators, resulting in a cascade reaction.

Review of Concepts

  • Innate vs. adaptive immunity
  • Three lines of defense
  • Components and connections of the immune system
  • Cellular characteristics of each granulocyte and agranulocyte type
  • Lymphatic circulation
  • Lymphoid organs and tissues
  • Inflammatory response mechanisms
  • Phagocytosis mechanisms and types of phagocytes
  • Interferon production and function
  • Complement activation, function, and cascade stages

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Chapter 14 - Fall 2024 PDF

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Test your understanding of the immune system with this comprehensive quiz. Questions cover all three lines of defense, the roles of white blood cells, and the interaction of various immune components. Perfect for students looking to reinforce their knowledge on immunology.

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