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Questions and Answers
What is the main function of the Adaptive arm of the immune system?
What is the main function of the Adaptive arm of the immune system?
What is the function of sebaceous oil glands in the skin?
What is the function of sebaceous oil glands in the skin?
Which of the following is an example of a cellular defense in the Internal division of the Innate immune system?
Which of the following is an example of a cellular defense in the Internal division of the Innate immune system?
What is the function of Natural Killer (NK) cells?
What is the function of Natural Killer (NK) cells?
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What is the role of interleukins in the immune response?
What is the role of interleukins in the immune response?
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What is the physiological response to tissue damage characterized by vasodilation, increased vascular permeability, and increased blood flow to the affected area?
What is the physiological response to tissue damage characterized by vasodilation, increased vascular permeability, and increased blood flow to the affected area?
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What is the role of fever in the immune response?
What is the role of fever in the immune response?
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What is the function of cilia in the Airways?
What is the function of cilia in the Airways?
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What is the direct cause of pain in the context of inflammation?
What is the direct cause of pain in the context of inflammation?
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Which of the following statements about fever is true?
Which of the following statements about fever is true?
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What is the primary function of antihistamines in the context of inflammation?
What is the primary function of antihistamines in the context of inflammation?
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What is the result of the body's perception of an increased temperature setpoint during fever?
What is the result of the body's perception of an increased temperature setpoint during fever?
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What is a benefit of fever in the context of infection?
What is a benefit of fever in the context of infection?
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What is the importance of inflammation and fever in certain situations?
What is the importance of inflammation and fever in certain situations?
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Study Notes
The Immune System
- The immune system has two main divisions: Adaptive and Innate
- The Adaptive arm responds specifically to pathogens, targeting and destroying them
- The Innate arm responds non-specifically, providing a first line of defense against invading pathogens
Innate Immune System
- The Innate system has no memory, so it cannot adapt to or remember previous infections
- It is the first line of defense, providing immediate protection against infection
- The Innate system has two main divisions: External and Internal
External Division of Innate Immune System
- The External division includes:
- Skin (epidermis) and mucous membranes
- Skin is made up of epithelia, with stratified squamous epithelia in the epidermis
- Sebaceous oil glands release oil with unsaturated fatty acids, making it difficult for microbes to grow
- Sweat helps to cool the body and wash away microbes
- Hair traps particles, and mucus and secretions contain enzymes (defensins and lysozymes) that kill pathogens
- Cilia in the Airways help to move mucus and trapped pathogens out of the body
Internal Division of Innate Immune System
- The Internal division includes:
- Cellular defenses (phagocytic cells)
- Chemical responses (complement proteins and cytokines)
- Physiological responses (inflammation and fever)
Phagocytic Cells
- Phagocytic cells engulf and destroy pathogens
- Examples include:
- Neutrophils (target bacterial pathogens)
- Macrophages (target and engulf pathogens, can also present antigens to the Adaptive immune system)
- Natural Killer (NK) cells (target and destroy pathogens, release perforins and granzymes)
Complement Proteins and Cytokines
- Complement proteins are released in response to pathogens and support the Innate immune response
- Cytokines are signaling molecules that complement the Innate and Adaptive immune responses
- Examples of cytokines include:
- Interleukins (call upon white blood cells for help)
- Interferons (released by virus-infected cells, trigger T cell response)
Physiological Responses
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Inflammation is a short-term response to tissue damage, characterized by vasodilation, increased vascular permeability, and increased blood flow to the affected area
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Fever is a physiological response to infection, where the body raises its temperature to make the environment inhospitable to pathogens.### Inflammation
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Redness occurs due to increased blood flow to the affected area, bringing heat from the body.
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Pain occurs due to pressure on nociceptors (pain receptors) from fluid buildup or direct damage, and stimulation by prostaglandins, histamines, and bradykinins.
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Swelling occurs due to fluid leakage, which is targeted by anti-inflammatory drugs.
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NSAIDs target prostaglandins, antihistamines target histamine, and some drugs target bradykinins.
Fever
- Fever is a physiological response to pyrogens, which stimulate heat.
- Pyrogens can be pathogens or cytokines, and they travel to the hypothalamus, the control center of the autonomic nervous system.
- The hypothalamus sets the body's temperature level, which is normally 38°C, but is increased by pyrogens to 40-41°C.
- The body perceives this increased temperature as normal, so it feels cold at 38°C, leading to shivering.
- Shivering causes muscles to contract and relax, releasing heat, and blood vessels to constrict, pulling heat from the periphery to the body core.
- Benefits of fever include:
- Increased immune cell function
- Decreased pathogen reproducibility
Importance of Inflammation and Fever
- Inflammation and fever are beneficial to a point, but can also be harmful if excessive.
- It's not always necessary to try to eliminate them immediately, as they can be beneficial in certain situations.
The Immune System
- The immune system consists of two main divisions: Adaptive and Innate, with distinct functions and responses to pathogens.
Innate Immune System
- The Innate system lacks memory, making it incapable of adapting to or remembering previous infections.
- It provides immediate protection against infection, and has two main divisions: External and Internal.
External Division of Innate Immune System
- The External division includes:
- Skin (epidermis) and mucous membranes, which provide physical barriers to pathogens
- Skin features that inhibit microbial growth, such as sebaceous oil glands and sweat
- Hair traps particles, and mucus and secretions contain enzymes (defensins and lysozymes) that kill pathogens
- Cilia in the Airways help move mucus and trapped pathogens out of the body
Internal Division of Innate Immune System
- The Internal division includes:
- Cellular defenses (phagocytic cells, such as neutrophils, macrophages, and Natural Killer cells) that engulf and destroy pathogens
- Chemical responses (complement proteins and cytokines) that support the Innate immune response
- Physiological responses (inflammation and fever) that aid in eliminating pathogens
Phagocytic Cells
- Phagocytic cells engulf and destroy pathogens, with examples including:
- Neutrophils, which target bacterial pathogens
- Macrophages, which target and engulf pathogens, and can present antigens to the Adaptive immune system
- Natural Killer (NK) cells, which target and destroy pathogens, releasing perforins and granzymes
Complement Proteins and Cytokines
- Complement proteins and cytokines (such as interleukins and interferons) support the Innate immune response
- Cytokines are signaling molecules that aid in both Innate and Adaptive immune responses
Physiological Responses
- Inflammation is a short-term response to tissue damage, characterized by vasodilation, increased vascular permeability, and increased blood flow to the affected area
- Fever is a physiological response to infection, where the body raises its temperature to make the environment inhospitable to pathogens
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Description
Learn about the two main divisions of the immune system, including the Innate Immune System and its role in providing immediate protection against infection. Discover how the Adaptive arm responds specifically to pathogens.
