Pathogens and Infectious Agents

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Questions and Answers

What is the central characteristic that distinguishes adaptive immunity from innate immunity?

  • Adaptive immunity provides a specific response. (correct)
  • Adaptive immunity operates mainly through phagocytosis.
  • Adaptive immunity is nonspecific.
  • Adaptive immunity has a fast response time.

Which immunoglobulin is primarily associated with allergic responses?

  • IgM
  • IgE (correct)
  • IgA
  • IgG

Which type of hypersensitivity reaction is primarily mediated by IgM and IgG?

  • Type IV hypersensitivity.
  • Type III hypersensitivity.
  • Type II hypersensitivity. (correct)
  • Type I hypersensitivity.

What is a distinctive feature of Type IV hypersensitivity reactions?

<p>They involve a delay of 24-48 hours after exposure. (A)</p> Signup and view all the answers

Which of the following statements about the humoral immune system is true?

<p>It depends on the secretion of antibodies by B cells. (B)</p> Signup and view all the answers

What is the term for an increase in the amount of a microorganism at a given location?

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

Which stage of infection follows the incubation period?

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

What type of infection occurs when normally harmless microbes become pathogenic?

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

What test is used to determine the identity of bacteria?

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

Which group of bacteria appears purple after a Gram stain?

<p>Gram-positive Bacteria (D)</p> Signup and view all the answers

What is a hospital-acquired infection called?

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

What describes a pathogen’s ability to cause disease?

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

Which of the following is not a stage of infection?

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

What is the primary purpose of human leukocyte antigen (HLA) in the body?

<p>To allow the immune system to recognize self from non-self cells (B)</p> Signup and view all the answers

Which type of immunity is generated from vaccination?

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

What is a common treatment for anaphylaxis during an allergic reaction?

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

What type of transplant involves tissues from the same individual?

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

Which of the following is NOT a type of transplant rejection?

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

What is the primary function of the bone marrow in the immune system?

<p>Produces all immune cells (A)</p> Signup and view all the answers

Which primary lymphoid organ is responsible for T-cell maturation?

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

What is the difference between incidence and prevalence in a medical context?

<p>Incidence refers to new cases while prevalence refers to all cases (D)</p> Signup and view all the answers

What role do lymph nodes play in the immune system?

<p>Filter fluid from tissues and proliferate immune cells (B)</p> Signup and view all the answers

How does the spleen contribute to the immune system?

<p>Acts as a massive lymph node and filters blood (B)</p> Signup and view all the answers

What is indicated by a bacterial culture's sensitivity testing?

<p>Assesses the effectiveness of various antibiotics against the bacteria (D)</p> Signup and view all the answers

Which of the following best describes the innate immune system?

<p>Provides immediate defense against pathogens (D)</p> Signup and view all the answers

Which statement about the thymus is true?

<p>It shrinks after puberty but remains active in T-cell maturation (B)</p> Signup and view all the answers

Which type of pathogen is characterized as a single-celled organism that can cause disease?

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

Which of the following bacteria is NOT mentioned as a common cause of infection?

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

What is the correct sequence of steps during a viral infection?

<p>Attachment, Uncoating, Replication (C)</p> Signup and view all the answers

Which route of transmission involves the transfer of pathogens via an insect bite?

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

Which step in establishing infection involves the pathogen avoiding the host's immune defenses?

<p>Avoid Host Defenses (B)</p> Signup and view all the answers

Which of the following is not a common shape of bacteria?

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

What type of infection is caused by organisms like tinea and candida?

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

Which of these routes of transmission involves touching contaminated surfaces?

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

What is the primary target of HIV in the immune system?

<p>CD4 lymphocytes (A)</p> Signup and view all the answers

What condition is characterized by a compromised immune system that may lead to opportunistic infections?

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

Which of the following is a common cause of immunodeficiency?

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

What does viral load measure in a person infected with HIV?

<p>Concentration of the virus (C)</p> Signup and view all the answers

What is the main bacterial cause of Urinary Tract Infections (UTIs)?

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

What is the importance of antiretroviral therapy in managing HIV?

<p>It decreases viral load and spread of the virus (B)</p> Signup and view all the answers

Which stage of HIV infection is characterized by a decline in viral replication and symptoms?

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

Which of the following describes leukemia?

<p>Cancer of bone marrow cells (A)</p> Signup and view all the answers

Flashcards

Colonization

The increase in the number of microorganisms in a specific location, indicating growth and replication.

Virulence

The ability of a pathogen to cause disease.

Nosocomial Infection

An infection acquired within a hospital or clinical setting.

Opportunistic Infection

An infection caused by microbes that usually don't cause disease, but take advantage of weakened conditions.

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Exposure

The initial stage where a person is exposed to a pathogen.

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Incubation

The time between exposure to a pathogen and the appearance of symptoms.

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Prodrome

The stage where mild symptoms start to appear.

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Acute

The stage with the most severe symptoms.

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Pathogens

Organisms that cause disease to their host.

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Protozoa

Single-celled organisms that can cause harm.

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Mycotic Infections

Fungal infections.

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Bacteria

Tiny organisms that cause disease. They can be spherical, rod-shaped, or spiral.

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Establishing Infection

The process by which a pathogen enters a host, attaches, multiplies, and causes harm.

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Entrance (in infection)

The initial step where a pathogen gains access to the host's body.

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Adherence (in infection)

The pathogen clings to the host's cells, establishing a foothold.

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Colonization (in infection)

The process by which a pathogen multiplies and grows within the host's body.

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Anaphylaxis

An extreme allergic reaction involving two or more bodily systems, typically characterized by hives (urticaria) and respiratory distress. This life-threatening condition can be treated with epinephrine.

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Human Leukocyte Antigen (HLA)

Proteins present on the surface of almost every cell in the body, acting as unique identifiers for the immune system. These proteins are crucial for recognizing self from non-self tissues.

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Autologous Transplant

A type of organ transplant where the donor and recipient are the same individual, minimizing the risk of rejection due to identical HLA profiles.

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Allogenic Transplant

A type of organ transplant where the donor and recipient are different individuals, requiring close HLA matching to reduce the likelihood of immune system rejection.

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Autoimmune Disease

A condition when the immune system mistakenly attacks the body's own tissues, leading to various symptoms depending on the specific target and immune cells involved.

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Adaptive Immunity

A type of immunity characterized by the immune system's ability to specifically target and destroy foreign invaders.

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Primary Immune Response

A type of immune response that is activated when the body is exposed to a pathogen for the first time.

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Secondary Immune Response

A type of immune response that is activated when the body is exposed to a pathogen that it has encountered before.

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Cytotoxic T cells

Immune cells that specifically target and destroy infected or abnormal cells.

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Antibodies

Molecules produced by B cells that specifically bind to antigens, marking them for destruction.

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Hematopoiesis

The process of forming blood cells, including immune cells.

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Thymus

A primary lymphoid organ responsible for the maturation of T-cells.

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Lymphatics

A network of vessels and tissues that help filter fluids and remove debris from the body, also important in immune surveillance.

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Spleen

A large lymphoid organ that acts as a filter for the blood, removes old blood cells and debris, and houses white pulp (immune cells).

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Innate Immune System

The part of the immune system that is the first line of defense against pathogens, it is non-specific and does not require prior exposure to a pathogen.

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Adaptive Immune System

The part of the immune system that is specific to each pathogen and requires prior exposure to develop an immune response.

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Culture

The process of growing bacteria from a patient sample in a laboratory to identify the type of bacteria present.

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Sensitivity

The process of testing bacterial cultures against different antibiotics to determine which antibiotics will be most effective in killing the bacteria.

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Immunodeficiency

A condition where the immune system is weakened, making the body more susceptible to infections.

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HIV

A virus that specifically attacks CD4+ T cells, crucial for immune responses.

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Latent HIV

The stage of HIV infection where symptoms are mild or absent, but the virus is active.

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AIDS

The final stage of HIV infection where the immune system is severely compromised.

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Viral load

The concentration of HIV in a person's blood, indicating the virus's ability to spread.

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Leukemia

Cancer of the bone marrow cells, affecting the production of blood cells.

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Lymphoma

Cancer of the lymphatic system, affecting lymph nodes and other tissues.

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Urinary tract infection (UTI)

A type of bacterial infection that commonly affects the urinary tract, especially in women.

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Study Notes

Pathogens

  • Pathogens are organisms that cause disease in their host.
  • Common causes of infection include bacteria (e.g., Streptococcus pyogenes, Streptococcus pneumoniae, E. coli), viruses (e.g., coronavirus, rhinovirus, influenza, herpes simplex), protozoa (e.g., giardia, malaria), fungi (e.g., tinea, candida), and helminths (e.g., pinworm, tapeworm).
  • Bacteria come in different shapes: cocci (spherical), bacilli (rod-shaped), and spirilla (spiral).

Bacteria Cell Anatomy

  • Bacteria have a cell wall, cell membrane, ribosomes, a capsule, flagellum, a pilus, and a nucleoid (containing DNA).

Bacteria Movement

  • Bacteria can move using flagella.

Viral Infection Steps

  • Viral infection steps include attachment, penetration, uncoating, replication, assembly, and release.

Protozoa

  • Protozoa are single-celled organisms.
  • Examples include Malaria and Giardia.

Fungi

  • Fungi are important pathogens
  • An example is tinea infections

Helminths

  • Helminths are worms
  • Examples include pinworms and tapeworms.

Routes of Transmission and Infection

  • Routes of infection include aerosol, airborne, droplet contact, fomite contact, direct contact, vector transmission, oral transmission, and zoonotic transmission.
  • Establishing infection involves the following steps:
    • Entrance
    • Adherence
    • Colonization
    • Avoidance of host defenses
    • Creating injury to host

Stages of Infection

  • Exposure
  • Incubation
  • Prodrome
  • Acute
  • Convalescent
  • Resolution

Testing for Microbes (focus on bacteria)

  • Goal: Identify bacteria types.
  • Gram Stain: Distinguishes bacteria into gram-positive and gram-negative categories
  • Culture: Provides bacterial identification.
  • Sensitivity: Determines suitable antibiotics for treatment.

Gram Stain

  • Gram positive bacteria retain the dye, appearing purple after staining.
  • Gram negative bacteria lose the dye, appearing red after staining. The difference lies in the structure of the cell wall.

Culture and Sensitivity

  • Culture: Growing a patient sample in a lab to identify the bacteria.
  • Sensitivity: Subjected the specific bacterial culture to a variety of different antibiotics to determine the most effective treatment for the pathogen/infection.

Tuberculosis (bacteria)

  • Tuberculosis symptoms include (but are not limited to) [symptoms not specified in text]

Primary Lymphoid Organs

  • Bone Marrow; site of hematopoiesis (production of blood cells), site of B-cell maturation
  • Thymus: site of T cell maturation
  • Lymph Nodes: immune surveillance, filter fluid from tissues
  • Spleen: acts as a massive lymph node filtering antigens

Innate vs. Adaptive Immune System

  • The immune system defends against pathogens.
  • Innate: Non-specific (fast response).
  • Adaptive: (slow response).

Humoral Immunity

  • Humoral immune system: antibodies and the production of antibodies. Its related to the immunity produced by the humoral immune response and hypersensitivity reactions.
  • The 5 immunoglobulins (antibodies):
    • IgG
    • IgA
    • IgM
    • IgE
    • IgD

Hypersensitivity Reactions

  • Four types of hypersensitivity reactions based on the involved immune system components
  • Type I: IgE and mast cells [examples and characteristics]
  • Type II: IgM/IgG, cytotoxic responses [examples and characteristics]
  • Type III: Antigen-Antibody Complex, immune complex [examples and characteristics]
  • Type IV: Cell-mediated, 24-48 hours after exposure [characteristics]
  • Allergic response
  • Risk of anaphylaxis (extreme allergic response)
  • Risk factors (body systems involved).

Active and Passive Immunity

  • Goal: IMMUNITY
  • Vaccine types [inactivated, attenuated, toxoid, subunit, conjugate]
  • Types of transplants (autologous and allogenic)
  • Types of rejection

Immunodeficiency and HIV

  • Immunodeficiency: a compromised immune system, may be temporary or permanent.
  • Causes include HIV infection.
  • HIV: a virus that targets CD4 helper T-cells [characteristics]
  • Viral Load: concentration of the virus

WBC disorders (Hodgkin's vs. Non-Hodgkins Lymphoma)

  • Hodgkin lymphoma: localized group of lymph nodes
  • Non-Hodgkin lymphoma: diffuse groups of lymph nodes
  • Location of spread
  • Other specified features relevant to disease types
  • Leukemia: cancer of the bone marrow

Urinary Tract Infections (UTIs)

  • E. coli responsible for 75-95% of UTIs in humans.
  • Upper UTI's (e.g., Pyelonephritis) symptoms vs Lower UTI's (e.g., Cystitis) symptoms

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