Endotoxins and Types of Immunity

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Questions and Answers

What portion of lipopolysaccharide (LPS) is responsible for the toxicity of endotoxins?

O-antigen

Peptidoglycan

Lipid A (correct)

Polysaccharide Core

Which of the following is an example of a physical barrier in natural immunity?

Th1 cells

Memory B cells

Antibodies

Cough reflex (correct)

What type of immunity primarily involves the action of antibodies?

Humoral Immunity (correct)

Cell-Mediated Immunity

Innate Immunity

Natural Immunity

What is a consequence of endotoxin release from Gram-negative bacteria after they die?

Endotoxic shock Signup and view all the answers

Which type of T-lymphocyte is primarily responsible for directly attacking infected cells?

Cytotoxic T cells Signup and view all the answers

What must organisms do to effectively colonize a host?

Adhere to the epithelium Signup and view all the answers

What is an example of a mechanism of dissemination of infectious agents?

Direct contact with infected individuals Signup and view all the answers

Which of the following modes of transmission is most commonly associated with airborne pathogens?

Inhalation of respiratory droplets Signup and view all the answers

What characterizes a secondary infection?

It is caused by opportunistic pathogens after the host's immune system is weakened. Signup and view all the answers

Which of the following best describes a latent infection?

It remains clinically silent until triggered. Signup and view all the answers

How is a sporadic disease defined?

It occurs occasionally in a population. Signup and view all the answers

What distinguishes an epidemic disease from an endemic disease?

An epidemic disease affects a large number of people in a short period. Signup and view all the answers

What is a mixed infection?

Two or more infections or organisms affecting a host. Signup and view all the answers

Which type of infection develops slowly and is typically long-lasting?

Chronic infection Signup and view all the answers

What is the primary method by which infectious diseases can affect populations?

Via direct transmission through air or contact. Signup and view all the answers

What represents the signs of infectious disease?

Observable and measurable objective changes. Signup and view all the answers

Which type of infection is confined to one area of the body?

Local infection Signup and view all the answers

What type of infection starts as a local infection and then spreads to other parts of the body?

Focal infection Signup and view all the answers

Which pathogen commonly spreads through vector-borne transmission specifically causing malaria?

Anopheles mosquito Signup and view all the answers

What is the primary characteristic of iatrogenic infections?

Result from medical treatment or procedures Signup and view all the answers

What distinguishes opportunistic infections from other types?

They predominantly affect immunocompromised hosts. Signup and view all the answers

What is bacteremia?

Presence of bacteria in the blood Signup and view all the answers

Which type of infection originates from the host's microbiota?

Autogenous infection Signup and view all the answers

Which infection spreads through blood and lymph as a result of a medical procedure?

Iatrogenic infection Signup and view all the answers

Which cell type is NOT associated with phagocytosis?

Basophils Signup and view all the answers

What is one key function of the inflammatory response?

Reinforces the body's defense against pathogens Signup and view all the answers

Which bacterium is known to produce a potent toxin that disrupts intestinal cell functioning?

Bacillus cereus Signup and view all the answers

What term describes the ability of the immune response to remember and recognize microorganisms?

Immunological memory Signup and view all the answers

Which type of toxin is produced by Gram-positive bacteria and does not require bacterial death?

Exotoxin Signup and view all the answers

What is NOT a sign of inflammation?

Temperature decrease Signup and view all the answers

Which system is NOT involved in the immune response?

Cardiovascular system Signup and view all the answers

What can compromise the effectiveness of immunological memory?

Radiation exposure Signup and view all the answers

What is the role of skin in the human body?

To act as a barrier to microorganisms Signup and view all the answers

What defines an opportunistic pathogen?

Causes disease when the host is immunocompromised Signup and view all the answers

Which of the following is an example of a cleansing mechanism in the body?

Thick mucus plug in the cervical opening Signup and view all the answers

Which statement accurately describes mutualism in symbiotic relationships?

Both organisms benefit from the relationship Signup and view all the answers

What is the function of lysozymes in the body?

Destroying bacterial cell walls Signup and view all the answers

How does the relationship in commensalism differ from mutualism?

One organism benefits without affecting the other Signup and view all the answers

Which of the following best represents the term indigenous microbiota?

Microorganisms that permanently inhabit a body site Signup and view all the answers

What is an example of a cleansing mechanism involving the respiratory tract?

Cilia in the trachea moving particles out Signup and view all the answers

Study Notes

Endotoxins

Composed of lipopolysaccharide (LPS), found only in Gram-negative bacteria.
Toxicity arises from the Lipid A portion of LPS.
Released upon bacterial death and cell wall lysis.
Symptoms of exposure include fever, chills, hypotension, granulocytosis, and disseminated intravascular coagulation.
Endotoxic shock is often a result of Gram-negative septicemia.

Types of Immunity

Natural/Innate Immunity: Includes physical barriers (skin, urine flushing), and physiological barriers (vaginal acid pH).
Adaptive/Acquired Immunity: Involves antibodies, complement system, memory B and T cells, categorized into:
- Humoral Immunity: Action of antibodies in body fluids.
- Cellular Immunity: T-lymphocytes directly attacking infected cells.

Invasion and Dissemination

Invasion involves penetrating and growing in host tissues; varies by organism.
Dissemination is the spread of pathogens to distant body sites, commonly through blood or lymph.

Routes of Transmission

Airborne, food and waterborne, and vector-borne transmissions are key methods of pathogen spread.
Examples: Anopheles mosquitoes transmit malaria; Aedes mosquitoes transmit dengue; cockroaches can spread diarrhea.

Types of Infections

Local Infection: Confined to a specific area (e.g., boils, abscesses).
Focal Infection: Originates locally, spreads to other areas (e.g., tonsillitis).
Iatrogenic Infection: Resulting from medical procedures (e.g., post-surgery wounds).
Systemic Infection: Spreads through blood and lymph.
Opportunistic Infection: Occurs in immunocompromised hosts or when pathogens enter a different body part.
Secondary Infection: Follows primary infection, exploiting a weakened immune system.
Latent Infection: Clinically silent until reactivation occurs, potentially causing severe illness later.

Disease Classification

Sporadic Disease: Occurs occasionally.
Endemic Disease: Constantly present in a specific location or population.
Epidemic Disease: Affects a large number of people rapidly.
Pandemic Disease: Spreads across a larger region globally.

Effects of Infectious Disease

Signs: Objective, measurable changes in the host (e.g., temperature, swelling).
Symptoms: Subjective experiences reported by the host (e.g., pain, fatigue).

Immune Defense Mechanisms

Physical barriers include skin and mucosal surfaces.
Cleansing Mechanisms: Cough/sneeze reflex, nasal hair, cilia in the respiratory tract.
Antimicrobial Substances: Lysozymes destroy bacterial cell walls; bile salts disrupt membranes.

Microbial Flora

Indigenous microbiota are normal flora residing in or on the body.
Types:
- Resident Microbiota: Permanently inhabit and colonize areas for extended periods.
- Transitory Microbiota: Temporarily inhabit a part of the body.

Toxins

Classified as:
- Exotoxins: Released by live bacteria; can cause severe damage even without bacterial death (includes cytotoxins, neurotoxins).
- Endotoxins: Released from dying Gram-negative bacteria and can trigger strong immune responses.

Inflammation

Protective response involving swelling, redness, heat, and pain, signaling potential tissue damage.
Phagocytes, including neutrophils and macrophages, play crucial roles during inflammation.

Immune Response

Essential for protecting against pathogenic microorganisms; can fail under immunocompromised states (radiation, chemotherapy).
Provides memory to recognize and respond to future infections.

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Description

This quiz covers the concept of endotoxins, focusing on their composition as lipopolysaccharides found in Gram-negative bacteria. Additionally, it discusses the two types of immunity: natural/innate immunity and the physical barriers that protect the body against infections. Test your knowledge on these critical concepts in immunology.