TEST 2: Inflammation Flashcards
What is the immune system?
A diverse collection of disease fighting cells in the blood, lymph, tissues, and organs throughout the body
-Lymphatic system:
-adenoids/ tonsils
-thymus
-bone marrow
-bronchus associated lymphoid tissue
-axillary lymph nodes
-intestine/ Peyers patches
-spleen
-inguinal lymph nodes
-appendix
$ Benefits of acute inflammation
-Acute inflammation:rapid and localized response that aims to eliminate the cause of cell injury and initiate repair process
-triggers the release of growth factors and cytokines to promote tissue repair/ regeneretion
-helps isolate and contain pathogens
-primes the adaptive immune system for pathogen recognition
$ Drawback of chronic inflammation
-Prolonged, systemic inflammatory response that persists over a longer period
-can lead to progressive tissue damage and fibrosis, impairing organ function
-may trigger autoimmune disease
-contributes to insulin resistance, dyslipidemia, cardiovascular risk
-associated with DNA damage, cell mutations, increased risk of cancer
Key components of immune system
- Blood
- Lymphatic system
- Solid organs (thymus and appendix)
- Bones
How the blood helps the immune system
-WBC’s are the primary cells of the immune system and are categorized into neutrophils, lymphocytes monocytes, eosinophils, and basophils (each has a specific role in immune response)
How the lymphatic system helps the immune response
- Lymph nodes: bean shaped structures that filter lymph fluid and trap pathogens
- Tonsils and Adenoids: tissues at the back of the throat that help prevent infections from entering the body
- Spleen: acts as a blood filter, removing old or damaged RBC’s and helping to fight infections
- Peyer’s patches: are found in the intestines and are part of the gut- associated lymphoid tissue, helping protect against pathogens in GI tract
How solid organs help the immune system
- Thymus: located behind the breastbone, thymus plays a critical role in the development and maturation of T lymphocytes
- Appendix: recent studies suggest may play a role in immune function and gut health
How bones help the immune system
Bone marrow: spongy tissue found in the center of bones that is responsible for producing all blood cells
Innate immunity barriers
- first line of defense
-layers of protection: skin/ mucous membranes, cells and secretory molecules (low pH of stomach acid and urine), ciliary activity
-this response is always at work
Innate immunity inflammatory response
-Second line of defense
-vascular response, plasma protein response, and cell mediated response
-able to respond immediately to invasion
Key roles of the immune system
- Protect against pathogens (B and T cells, macrophages, dendritic cells that work together to recognize and target specific pathogens)
- Isolate and remove foreign substances (dendritic cells capture and present foreign antigens to other immune cells for recognition/ response)
- Immune surveillance: dynamic process where cells constantly survey the body for abnormal cells (NK cells detect and eliminate aberrant cells before they develop into tumors; cytotoxic T cells can recognize/ destroy cancer cells)
Inflammatory response
A key component of the innate immune response and is triggered in response to tissue damage, infection, or threat.
-During inflammation, blood vessels dilate, allowing immune cells to reach the site of injury/ infection quickly (helps to contain and eliminate pathogens)
$ Inmate and adaptive immunity interaction
-The innate system provides immediate, generalized defense against a wide array of threats, and also is responsible for priming the adaptive immune response.
-Innate immune cells present antigens to adaptive immune cells, activating them and guiding their specific responses to pathogens.
Stages of inflammatory response
- Stage 1: recognition and triggering stage
- Stage 2: Inflammatory mediator release
- Stage 3: immune cell activation and phagocytosis
- Resolution and tissue repair
Stage 1: recognition and triggering of inflammatory response
-At the onset of inflammation, immune cells recognize danger signals such as pathogen-associated molecular patterns (PAMP’s) or damage- associated molecular patterns (DAMP’s) through pattern recognition receptors (PRR’s)
-This recognition initiates a cascade of events leading to the release of pro inflammatory mediators like histamines, prostaglandins, and cytokines.
-initial vascular changes like vasodilation and increased permeability are crucial for promoting the influx of immune cells to the affected site.
-these cells play a pivotal role in eliminating pathogens and activating the adaptive immune response
Stage 2: inflammatory mediator response in inflammatory response
-Inflammatory mediators like TNF, interleukins, and chemokines, are release by immune cells and contribute to amplification of inflammatory response. They orchestrate the recruiting and activity of more immune cells, enhancing defense.
-The balance between pro and anti inflammatory mediators is crucial for ensuring an effective but controlled response, preventing excessive tissue damage but still fighting the threat
Stage 3: inflammatory mediator release in inflammatory response
-Neutrophils and macrophages play key roles in engulfing and destroying pathogens through phagocytosis. This not only eliminates the immediate threat but generates signaling molecules that regulate immune response and tissue repair.
-Concurrently, the activation of T and B cells occurs, leading to a tailored and specific response against pathogens that are invading, forming immunologic memory for future encounters
Stage 4: Resolution and tissue repair in the inflammatory response
-When the threat is neutralized and the immune system under control, anti inflammatory mediators (including growth factor beta and interleukin 10) dampen the inflammatory cascade, promoting the clearance of immune cells and initiation of tissue repair
-Tissue repair involves the regeneration of damage through proliferation of fibroblasts, deposition of collagen, and angiogenesis.
-Regenerative phase aims to restore normal tissue structure and function while minimizing scar formation
$ Vascular response to inflammation
-Inflammation characterized by rapid and dynamic changes in blood vessels that facilitate immune cell recruitment to the area of injury by:
-Vasodilation: relaxation of blood vessel walls to increase blood flow to site (triggered by histamine and prostaglandins creating redness/heat)
-Increased vascular permeability: permeability of blood vessels is enhanced, allowing immune and plasma proteins to move out of the blood stream into the tissues; is crucial for delivery of immune cells to infection)
-Formation of edema: leakage of fluid from blood vessels from the increased permeability and results in accumulation of fluid into the tissues (edema helps dilute toxins and provide a fluid environment for cells to work effectively)
