Host Resistance Overview Quiz

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Questions and Answers

What is the primary function of the immune system?

To recognize and adapt to the environment

To develop immunological memory against non-specific agents

To recognize foreign substances or microbes and neutralize or destroy them (correct)

To produce antibodies against all antigens

What is the key characteristic of specific immune response?

It is the first line of defense

It provides resistance to any microbe or foreign material

It has 'memory' and effectiveness increases on repeated exposure to the agent (correct)

It lacks immunological memory

What is the term for the development of white blood cells in the bone marrow of mammals?

Leukopoesis

Hematopoesis (correct)

Immunogenesis

Lymphopoesis

What is the role of dendritic cells in the immune system?

To recognize and respond to all antigens Signup and view all the answers

What is the term for the ability of the host to resist a particular disease or infection?

Immunity Signup and view all the answers

What is the outcome of the presence of antigen in the body?

Production of antibodies Signup and view all the answers

What is the key difference between innate and adaptive immune responses?

Innate response lacks immunological memory, while adaptive response has it Signup and view all the answers

What is the role of macrophages in the immune system?

To respond to all antigens Signup and view all the answers

What is the term for the science concerned with immune responses?

Immunology Signup and view all the answers

What is the primary function of the mucociliary blanket in the respiratory system?

To trap microbes and transport them away from the lungs Signup and view all the answers

Which of the following is NOT a physical barrier in the innate resistance?

Lysozyme Signup and view all the answers

What is the primary function of lactoferrin in the innate immune system?

To sequester iron from plasma Signup and view all the answers

What is the role of the alveolar macrophages in the respiratory system?

To phagocytose foreign particles and microorganisms Signup and view all the answers

What is the primary function of the GALT in the gastrointestinal tract?

To produce lysozyme Signup and view all the answers

What is the function of the Paneth cells in the gastrointestinal tract?

To produce antimicrobial substances Signup and view all the answers

What is the role of the urea in the genitourinary tract?

To act as a toxic metabolic end product against microorganisms Signup and view all the answers

What is the function of the lactobacilli in the vagina?

To create an unfavorable environment for microorganisms Signup and view all the answers

What is the role of the flushing action of tears in the eye?

To remove foreign particles and microorganisms from the eye Signup and view all the answers

What is the primary function of opsonization?

To coat microbes for recognition by phagocytic cells Signup and view all the answers

Which of the following is NOT a function of the complement system?

Stimulating the production of cytokines Signup and view all the answers

What is the result of the activation of the complement system?

Cell lysis and removal of pathogens Signup and view all the answers

Which of the following cytokines is involved in stimulating the growth and differentiation of immature leukocytes in bone marrow?

Colony stimulating factors (CSFs) Signup and view all the answers

What is the primary function of cytokines in the immune system?

To act as intercellular mediators and signaling molecules Signup and view all the answers

Which of the following is an example of an acute phase protein?

Surfactant protein A (SP-A) Signup and view all the answers

What is the function of lectin in the immune system?

To recognize and bind to pathogens Signup and view all the answers

Which of the following is NOT a function of chemokines?

Stimulating the production of cytokines Signup and view all the answers

What is the result of the activation of cytokines in the immune system?

Differentiation, proliferation, and apoptosis Signup and view all the answers

What is the immediate response of the body to injury or cell death?

Acute inflammation Signup and view all the answers

Which type of inflammation usually causes permanent tissue damage?

Chronic inflammation Signup and view all the answers

What is the role of selectins in the acute inflammatory response?

To act as adhesion molecules on activated capillary endothelial cells Signup and view all the answers

What is the term for the process by which neutrophils move through the endothelium of blood vessels into the surrounding tissue?

Diapedesis Signup and view all the answers

What is the term for the walled-off area formed when phagocytic cells can't destroy a pathogen?

Granuloma Signup and view all the answers

What is the result of the release of inflammatory mediators from injured tissue cells?

A cascade of events that result in the signs of inflammation Signup and view all the answers

What is the primary characteristic of acute inflammation?

The immediate response of the body to injury or cell death Signup and view all the answers

What is the term for the movement of neutrophils towards a chemical stimulus, such as a bacterial product?

Chemotaxis Signup and view all the answers

What is the term for the adhesion receptors on neutrophils that play a role in the acute inflammatory response?

Integrins Signup and view all the answers

What is the primary mode of action of cationic peptides against bacteria?

Damage to bacterial plasma membranes Signup and view all the answers

Which of the following is NOT a characteristic of defensins?

Linear, alpha-helical structure Signup and view all the answers

What is the primary function of bacteriocins?

Lethal activity against related bacterial species Signup and view all the answers

Which of the following cytokine categories is NOT listed in the text?

Anti-inflammatory cytokines Signup and view all the answers

What is the name of the peptide produced by a variety of cells, including neutrophils and epithelial cells?

Cathelicidin Signup and view all the answers

What is the role of the host complement system in innate immunity?

Three outcomes: inflammation, cell lysis, and opsonization Signup and view all the answers

What is the characteristic of the third class of cationic peptides?

Enriched for specific amino acids and exhibit regular structural repeats Signup and view all the answers

Which of the following is an example of a chemical mediator found in saliva?

Histatin Signup and view all the answers

What is the source of bacteriocins?

Normal microbiota Signup and view all the answers

Study Notes

Innate Host Resistance

Innate host resistance comprises physical and chemical barriers, as well as cellular and molecular responses that provide immediate defense against pathogens.
It is the first line of defense against microbial invasion and is a vital component of the immune system.

Immune System Overview

The immune system is composed of distributed cells, tissues, and organs that recognize and respond to foreign substances or microbes.
Immunity refers to the ability of the host to resist a particular disease or infection.

Immunity and Nonspecific Immune Response

Nonspecific immune response, also known as innate immunity, acts as the first line of defense against microbes and foreign materials.
It lacks immunological memory and does not differentiate between pathogens.
Specific immune response, also known as acquired or adaptive immunity, provides resistance to specific foreign agents and has "memory" that increases effectiveness with repeated exposure.

Antigens and Immune Responses

Antigens are recognized as foreign and invoke immune responses, ultimately resulting in B cell activation and antibody production.
Antibodies bind to specific antigens, inactivating or eliminating them, and other immune cells become activated.

White Blood Cells of Innate and Adaptive Immunity

White blood cells (WBCs) play a major role in both innate and adaptive immune responses.
Some WBCs mature prior to leaving the bone marrow and respond to all antigens as part of the innate immune system.
Other WBCs mature after leaving the bone marrow and become part of the adaptive immune response, responding to specific antigens.

Physical and Mechanical Barrier Defenses of Innate Resistance

Physical barriers, such as skin and mucous membranes, provide a first line of defense against microbial invasion.
These barriers are impacted by factors like nutrition, physiology, fever, age, and genetics, as well as personal hygiene, socioeconomic status, and living conditions.

Skin as a Physical Barrier

Skin is a strong mechanical barrier to microbial invasion due to the production of keratin by keratinocytes in the outer layer.
The skin environment is inhospitable to microbes, with features like pH, NaCl concentration, and periodic drying.

Mucous Membranes

Mucous membranes form a protective covering that resists penetration and traps many microbes.
They are bathed in antimicrobial secretions containing substances like lysozyme, lactoferrin, and lactoperoxidase.

Respiratory System

Turbulent air flow in the respiratory system deposits microbes onto mucosal surfaces, which are then trapped by mucous secretions.
The mucociliary blanket transports trapped microbes away from the lungs, and they are expelled through coughing or sneezing.

Gastrointestinal Tract

The stomach contains gastric acid, while the intestines shed columnar epithelial cells, produce pancreatic enzymes, and contain normal microbiota.
Other defense mechanisms in the gut include secretory IgA, bile, and intestinal enzymes.

Genitourinary Tract

The genitourinary tract has an unfavorable environment for foreign microbes due to low pH, urea, and other toxic metabolic end products.
The vagina has a low pH and contains lactobacilli, and the male urethra provides a distance barrier.

The Eye

The eye is protected by a mucus-secreting epithelial membrane, with mechanisms like flushing with tears, lysozyme, lactoferrin, and secretory IgA in tears.

Chemical Mediators in Innate Resistance

Inflammation is a nonspecific response to tissue injury or cell death, characterized by redness, warmth, pain, swelling, and altered function.
Acute inflammation involves the release of inflammatory mediators, margination, diapedesis, and extravasion.
Chronic inflammation is a slow process involving the formation of new connective tissue, causing permanent tissue damage.

Complement System

The complement system is composed of over 30 serum proteins that augment the antibacterial activity of antibody.
It has three major activities: defending against bacterial infections, bridging innate and adaptive immunity, and disposing of wastes.

Cytokines

Cytokines are soluble proteins or glycoproteins released by one cell population that act as intercellular mediators or signaling molecules.
They can be classified into three groups based on function: regulators of innate resistance mechanisms, regulators of adaptive immunity, and stimulators of hematopoiesis.

Acute Phase Proteins

Acute phase proteins are produced in response to bacterial infection, leading to the release of cytokines, liver stimulation, and acute phase protein production.
Examples include C-reactive protein (CRP), mannan-binding lectin (MBL), surfactant proteins A (SP-A) and D (Sp-D), which can bind bacterial surfaces and act as opsonins.

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Description

Test your knowledge on host resistance, the first line of defense against pathogens, including surface barriers and non-specific immune responses. Learn how the immune system recognizes and responds to foreign substances and microbes.