51 Questions
The recognition of microbes by the innate immune system is specific to the type of microbe.
False
Phagocytes express receptors for sialic acid residues on bacterial glycoproteins.
False
The innate immune system can be evaded by microbes that develop mutations in essential structures.
False
Lysozyme is present in all bodily secretions.
False
Sebaceous gland secretions have a role in physiochemical barriers.
True
Innate immunity recognizes unique structures present on host cells.
False
Cilia lining the trachea are part of the adaptive immune response.
False
Antibodies are a component of the innate immune response.
False
The skin acts as a physical barrier against infections, but its importance is only significant when an individual suffers from minor injuries.
False
All infections enter the body via the epithelial surface of the skin.
False
Macrophages are directly delivered from the bone marrow to the tissues.
False
Lysozyme is an example of an acute phase protein.
False
Neutrophils are the least abundant leukocytes in the blood.
False
Microglial cells are a type of macrophage that resides in the liver.
False
Cytokines of innate immunity are a type of soluble factor.
True
Interferons are produced by neutrophils.
False
Eosinophils are present in the blood and tissues as part of the adaptive immune system
False
The innate immune system is the second line of defense against infection
False
Lysozyme is a soluble factor produced by the adaptive immune system
False
The innate immune system produces specific reactions to each infectious agent
False
Natural killer cells are part of the adaptive immune system
False
Phagocytic cells are a type of physical barrier
False
The innate immune system is improved by repeated exposure to infection
False
Physical barriers are part of the adaptive immune system
False
The innate immune system is the second line of defense against infectious agents.
False
The innate immune system can recognize and respond to specific pathogens.
False
Innate immunity provides long-term protection against infections.
False
The innate immune system is responsible for the rejection of tissue grafts.
False
The innate immune system is present from birth and remains throughout life.
True
The innate immune system can be activated by the presence of tumorous cells.
False
The innate immune system is a specific defense mechanism against infections.
False
The innate immune system is able to distinguish between self and non-self.
False
Monocytes that enter extravascular tissues survive in these sites for short periods.
False
Macrophages are found in the connective tissues and in every organ in the body.
True
Phagocytosis is a process in which the phagocyte extends its plasma membrane around the host cells.
False
Phagocyte Oxidase converts molecular oxygen into reactive oxygen intermediates (ROIs) that are toxic to the host cells.
False
Nitric Oxide Synthase catalyzes the conversion of arginine to nitric oxide (NO) which is a microbicidal substance.
True
Inherited deficiency of Phagocyte Oxidase enzyme is the cause of an immunodeficiency disease called Chronic Lymphocytic Disease.
False
In Chronic Granulomatous Disease, phagocytes are able to eradicate intracellular microbes.
False
Macrophages stimulate NK cells by secretion of IL-10.
False
What does immunology refer to?
The study of immunity, cellular and molecular events that occur after exposure to microbes and other foreign macromolecules.
Which word is immunity derived from?
Immunitas
The innate immune system is the second line of defense against infections.
False
In the innate immune system, _________________ are always present as a first line of defense.
physical barriers, phagocytic cells, eosinophils, natural killer cells, blood-borne molecules
Match the following components of innate immunity:
Intact skin = Good physical barrier Phagocytes = Neutrophils, Monocytes, Macrophages Natural killer (NK) cells = Cell capable of killing infected cells Soluble factors = Interferons, Lysozyme, CRP, Complement
What is the function of macrophages?
Produce cytokines, secrete growth factors, stimulate NK cells, stimulate T lymphocytes, and perform phagocytosis.
What is immunology?
Immunology is the study of immunity, cellular and molecular events that occur after exposure to microbes and other foreign macromolecules.
Which system is the first line of defense against infectious agents?
Innate immune system
In the adaptive immune system, a specific reaction is produced to each infectious agent, which normally eradicates that agent. It must be stimulated with ______________ before it can be effective.
microbes
Match the components with the correct immune system:
Phagocytes, Natural killer cells = Innate immune system Lymphocytes, Antibodies = Adaptive immune system Interferons, Complement, Cytokines = Innate immune system
The innate immune system recognizes structures that are unique to host cells.
False
Study Notes
Adaptive Immunity
- Specific for antigens that may be microbial or non-microbial, not essential for survival
- May differ among microbes of the same type
- Microbes can evade adaptive immunity by mutating the antigens recognized by lymphocytes
Innate Immunity
- Recognizes structures that are shared by microbes, but not present on host cells
- Cannot be evaded by microbes
- Components:
- Intact skin (physical barrier)
- Phagocytes (Neutrophils, Monocytes, Macrophages)
- Natural killer (NK) cells
- Soluble factors (e.g. Interferons, Lysozyme, Acute phase proteins, Complement)
- Cytokines of innate immunity
Phagocytes
- Types: Neutrophils, Monocytes, Macrophages
- Function: Recognize and ingest microbes for intracellular killing
- Neutrophils:
- Most abundant leukocytes in the blood (4000-10,000/mm3)
- Called polymorphonuclear leukocytes (PMNs)
- Monocytes:
- Less abundant than neutrophils (500-1000/mm3)
- When traveled into tissues, called macrophages (monocytes/macrophage series)
Physical and Biochemical Defenses
- Exterior defense represented by physical and biochemical defenses
- Includes:
- Lysozyme in most secretions
- Sebaceous gland secretions
- Mucus secretion
- Spermine in semen
- Acid in stomach
- Potent biochemical substances (e.g. tears, lysozyme, complements)
- Skin and mucus membrane
- Cilia lining trachea
- Commensal organisms in gut and vagina
Recognition of Microbes by Innate Immune System
- Recognizes structures that are shared by microbes, but not present on host cells
- Examples:
- Phagocytes express receptors for bacterial LPS
- Phagocytes express receptors for terminal mannose residues on bacterial glycoproteins
- Phagocytes recognize and respond to ds RNA
- Neutrophils and macrophages express receptors for antibodies and complement proteins
Immunology
- Study of immunity, cellular and molecular events that occur after exposure to microbes and other foreign macromolecules
- Immune system:
- Defends against infections
- Recognizes and responds to tissue grafts
- Defends against tumor
- Produces highly specific antibodies for detecting molecules
- Divided into:
- Innate (Natural or Native) immunity
- Adaptive (Acquired or Specific) immunity
Functions of Immune System
- Defense against infections
- Recognition and response to tissue grafts
- Defense against tumor
- Production of highly specific antibodies for detecting molecules
Immunology
- Immunology is the study of immunity, cellular, and molecular events that occur after exposure to microbes and other foreign macromolecules.
- It began as a study of the response of the whole animal to infection.
- Derived from the Latin word "Immunitas", which means a reaction of the immune system to foreign substances including microbes and macromolecules.
Immune System
- The immune system has various functions, including:
- Defense against infections
- Recognizing and responding to tissue grafts
- Defense against tumors
- Antibodies as highly specific reagents for detecting molecules
- The immune system is divided into two parts:
- Innate (Natural or Native) immune system
- Adaptive (Acquired or Specific) immune system
Innate Immune System
- The innate immune system is always present and ready to recognize and eliminate microbes.
- It is the first line of defense against infectious agents.
- Examples of innate immune system defense mechanisms include:
- Physical barriers (e.g., skin, mucous membranes)
- Phagocytic cells (e.g., neutrophils, monocytes, macrophages)
- Eosinophils in the blood and tissues
- Natural killer cells (NK)
- Blood-borne molecules (e.g., lysozyme, acute phase proteins)
Adaptive Immune System
- The adaptive immune system is directed against microbial and non-microbial antigens.
- It produces specific reactions to each infectious agent, which normally eradicates the agent.
- It must be stimulated with microbes before it can be effective.
- It remembers the previous infectious agent and can prevent it (e.g., life-long immunity following infection).
Responses of Innate and Adaptive Immune Systems to Infection
- The innate immune system provides immediate defense against infection, while the adaptive immune system provides long-term protection.
- The innate immune system recognizes structures shared by microbes, whereas the adaptive immune system recognizes specific antigens.
Major Elements of Innate and Adaptive Immune Systems
- Innate immune system:
- Soluble factors (e.g., lysozyme, complement, acute phase proteins)
- Cells (e.g., phagocytes, natural killer cells)
- Physiochemical barriers (e.g., skin, mucous membranes)
- Adaptive immune system:
- Soluble factors (e.g., antibodies, lymphocyte-derived cytokines)
- Cells (e.g., lymphocytes)
- Physiochemical barriers (e.g., antibodies in mucosal secretions)
Recognition of Microbes by Innate Immune System
- The innate immune system recognizes structures shared by microbes, such as:
- Lipopolysaccharides (LPS) on bacterial surfaces
- Terminal mannose residues on bacterial glycoproteins
- Double-stranded RNA (dsRNA) found in many viruses
Components of Innate Immunity
- Intact skin: provides a physical barrier against infection
- Phagocytes (e.g., neutrophils, monocytes, macrophages): recognize and ingest microbes for intracellular killing
- Natural killer cells (NK): recognize and kill infected cells or tumor cells
- Soluble factors (e.g., interferons, lysozyme, acute phase proteins): provide biochemical defenses against infection
Functions of Macrophages
- Produce cytokines that are important mediators of the host defense
- Secrete growth factors and enzymes that serve to remodel injured tissue and replace it with connective tissue
- Stimulate natural killer cells by secretion of IL-12
- Stimulate T lymphocytes and respond to products of T cells
- Engulf and digest foreign substances and microorganisms through phagocytosis
Immunology
- Immunology is the study of immunity, cellular, and molecular events that occur after exposure to microbes and other foreign macromolecules.
- It began as a study of the response of the whole animal to infection.
- Derived from the Latin word "Immunitas", which means a reaction of the immune system to foreign substances including microbes and macromolecules.
Immune System
- The immune system has various functions, including:
- Defense against infections
- Recognizing and responding to tissue grafts
- Defense against tumors
- Antibodies as highly specific reagents for detecting molecules
- The immune system is divided into two parts:
- Innate (Natural or Native) immune system
- Adaptive (Acquired or Specific) immune system
Innate Immune System
- The innate immune system is always present and ready to recognize and eliminate microbes.
- It is the first line of defense against infectious agents.
- Examples of innate immune system defense mechanisms include:
- Physical barriers (e.g., skin, mucous membranes)
- Phagocytic cells (e.g., neutrophils, monocytes, macrophages)
- Eosinophils in the blood and tissues
- Natural killer cells (NK)
- Blood-borne molecules (e.g., lysozyme, acute phase proteins)
Adaptive Immune System
- The adaptive immune system is directed against microbial and non-microbial antigens.
- It produces specific reactions to each infectious agent, which normally eradicates the agent.
- It must be stimulated with microbes before it can be effective.
- It remembers the previous infectious agent and can prevent it (e.g., life-long immunity following infection).
Responses of Innate and Adaptive Immune Systems to Infection
- The innate immune system provides immediate defense against infection, while the adaptive immune system provides long-term protection.
- The innate immune system recognizes structures shared by microbes, whereas the adaptive immune system recognizes specific antigens.
Major Elements of Innate and Adaptive Immune Systems
- Innate immune system:
- Soluble factors (e.g., lysozyme, complement, acute phase proteins)
- Cells (e.g., phagocytes, natural killer cells)
- Physiochemical barriers (e.g., skin, mucous membranes)
- Adaptive immune system:
- Soluble factors (e.g., antibodies, lymphocyte-derived cytokines)
- Cells (e.g., lymphocytes)
- Physiochemical barriers (e.g., antibodies in mucosal secretions)
Recognition of Microbes by Innate Immune System
- The innate immune system recognizes structures shared by microbes, such as:
- Lipopolysaccharides (LPS) on bacterial surfaces
- Terminal mannose residues on bacterial glycoproteins
- Double-stranded RNA (dsRNA) found in many viruses
Components of Innate Immunity
- Intact skin: provides a physical barrier against infection
- Phagocytes (e.g., neutrophils, monocytes, macrophages): recognize and ingest microbes for intracellular killing
- Natural killer cells (NK): recognize and kill infected cells or tumor cells
- Soluble factors (e.g., interferons, lysozyme, acute phase proteins): provide biochemical defenses against infection
Functions of Macrophages
- Produce cytokines that are important mediators of the host defense
- Secrete growth factors and enzymes that serve to remodel injured tissue and replace it with connective tissue
- Stimulate natural killer cells by secretion of IL-12
- Stimulate T lymphocytes and respond to products of T cells
- Engulf and digest foreign substances and microorganisms through phagocytosis
Learn about the differences between adaptive and innate immunity, including their components and how microbes can evade the immune system. This quiz covers the basics of immunology and the role of lymphocytes, phagocytes, and natural killer cells.
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