17.5 Inflammation and Fever

Inflammation is the body's immediate response to injury or infection, characterized by redness, heat, swelling, and pain. It aims to eliminate the initial cause of cell injury, clear out damaged cells and tissues, and establish repair.

Cytokine: A small protein released by cells that has a specific effect on interactions and communications between cells.

Acute-phase proteins: Proteins whose plasma concentrations increase or decrease in response to inflammation.

Phagocytosis: The process by which a cell engulfs particles such as bacteria or cellular debris.

Inflammation is the body's immediate response to injury or infection, characterized by redness, heat, swelling, and pain. It aims to eliminate the initial cause of cell injury, clear out damaged cells and tissues, and establish repair.

Cytokine: A small protein released by cells that has a specific effect on interactions and communications between cells.

Acute-phase proteins: Proteins whose plasma concentrations increase or decrease in response to inflammation.

Phagocytosis: The process by which a cell engulfs particles such as bacteria or cellular debris.

Chronic inflammation is a prolonged inflammatory response that can last for months or years, often due to persistent infection, autoimmune response, or prolonged exposure to harmful agents. It involves the continuous presence of immune cells and can lead to tissue damage and disease.

Acute Inflammation: A rapid immune response to injury or infection characterized by redness, heat, swelling, and pain.

Cytokines: Signaling proteins released by cells that mediate and regulate immunity and inflammation.

Fibrosis: The thickening and scarring of connective tissue usually as a result of injury or long-term inflammation.

Rubor, or redness, is one of the five classic signs of inflammation, along with dolor (pain), calor (heat), tumor (swelling), and functio laesa (loss of function). It is a visible manifestation of the body's immune response to injury, infection, or irritation, and is characterized by a localized reddening of the affected area.

Inflammation: A protective response of the body's immune system to injury, infection, or irritation, characterized by redness, swelling, heat, and pain.

Vasodilation: The widening of blood vessels, which increases blood flow to the affected area and is a key component of the inflammatory response.

Erythema: Redness of the skin caused by increased blood flow, often associated with inflammation or other skin conditions.

Vasodilation is the widening of blood vessels resulting from relaxation of the muscular walls of the vessels. It increases blood flow to tissues and helps in thermoregulation and immune response.

Inflammation: A biological response to harmful stimuli, characterized by redness, swelling, heat, pain, and loss of function.

Nitric oxide: A signaling molecule that promotes vasodilation by relaxing smooth muscles in blood vessels.

Endothelial cells: Cells lining the interior surface of blood vessels, playing a crucial role in vascular functions including vasodilation.

A tumor is an abnormal growth of cells that can be either benign (non-cancerous) or malignant (cancerous). Tumors are a key aspect of the inflammatory response and can be associated with fever, as they can trigger an immune reaction in the body.

Inflammation: Inflammation is the body's immune response to injury, infection, or irritation, which can lead to the formation of tumors.

Fever: Fever is an elevated body temperature that can occur as a result of the body's inflammatory response, including the presence of tumors.

Neoplasia: Neoplasia is the abnormal and uncontrolled growth of cells, which can result in the formation of tumors.

Edema is the abnormal accumulation of fluid in interstitial tissues, leading to swelling. It can be caused by various factors, including infections that affect the circulatory and lymphatic systems.

Cytokines: Signaling proteins released by cells that mediate and regulate immunity, inflammation, and hematopoiesis.

Histamine: A compound involved in local immune responses that increases vascular permeability and leads to symptoms like swelling.

Lymphatic System: A network of tissues and organs that help rid the body of toxins, waste, and other unwanted materials through a fluid called lymph.

Calor is the Latin word for 'heat' and refers to the sensation of warmth or elevated temperature associated with various physiological processes, particularly in the context of inflammation and fever.

Inflammation: A localized protective response of the body's immune system to various stimuli, such as pathogens, damaged cells, or irritants, which is often characterized by redness, swelling, heat, and pain.

Fever: An elevation of the body's normal temperature, typically in response to an infection or other illness, as part of the body's immune response to fight off the underlying cause.

Pyrexia: The medical term for fever, referring to an abnormally high body temperature.

Dolor is the medical term used to describe the subjective experience of physical pain or discomfort. It is a fundamental component of the inflammatory response and a key indicator of various pathological conditions.

Inflammation: The body's protective immune response to irritation, injury, or infection, characterized by redness, swelling, heat, and pain.

Fever: An elevation of the body's normal temperature, often a symptom of an underlying illness or infection.

Nociception: The physiological process of detecting and transmitting signals of potential harm from the periphery to the central nervous system.

Prostaglandins are a group of lipid-based compounds that act as signaling molecules in the body, playing crucial roles in inflammation, fever, and other physiological processes. They are derived from arachidonic acid and are produced by various cells throughout the body.

Arachidonic Acid: A polyunsaturated fatty acid that serves as the precursor for the synthesis of prostaglandins and other eicosanoids.

Cyclooxygenase (COX): The enzyme responsible for the conversion of arachidonic acid into prostaglandin H2, the common precursor for various prostaglandins.

Eicosanoids: A class of lipid-derived signaling molecules that includes prostaglandins, leukotrienes, and thromboxanes, which regulate a wide range of physiological and pathological processes.

Bradykinin is a peptide that causes blood vessels to dilate (enlarge), leading to increased permeability and allowing immune cells to access affected tissues. It plays a crucial role in inflammation and pain signaling.

Kinin-Kallikrein System: A complex proteolytic cascade responsible for producing kinins like bradykinin.

Vascular Permeability: The ability of blood vessel walls to allow the passage of substances into and out of the bloodstream.

B2 Receptor: A receptor that primarily mediates most of the physiological effects of bradykinin.

Functio laesa, or impaired function, refers to the disruption or impairment of normal physiological function in the body as a result of disease, injury, or other pathological processes. It is a key concept in the understanding of inflammation and fever, as these conditions can lead to various functional impairments within the affected tissues and systems.

Inflammation: The body's protective response to injury, infection, or irritation, characterized by redness, swelling, heat, and pain.

Fever: An elevated body temperature above the normal range, often a sign of an underlying infection or inflammatory process.

Homeostasis: The body's ability to maintain a stable, balanced internal environment despite changes in external conditions.

Fever is an elevated body temperature that occurs as part of the body's immune response to infection or inflammation. It acts as a defense mechanism to inhibit the growth of pathogens and enhance immune function.

Pyrogen: A substance, typically produced by bacteria, that induces fever.

Cytokine: Small proteins released by cells that have a specific effect on cell-to-cell communication and immune responses.

Hypothalamus: A region of the brain responsible for regulating various bodily functions, including temperature control.

Pyrogens are substances that cause an increase in body temperature by triggering the hypothalamus to elevate the body's set point. They can be exogenous, originating from outside the body such as bacteria, or endogenous, produced within the body like cytokines.

Inflammation: A biological response to harmful stimuli marked by redness, heat, swelling, and pain.

Cytokines: Small proteins released by cells that have a specific effect on interactions and communications between cells.

Hypothalamus: A region of the brain responsible for regulating body temperature among other functions.

Fever is an elevated body temperature that occurs as part of the body's immune response to infection or inflammation. It acts as a defense mechanism to inhibit the growth of pathogens and enhance immune function.

Pyrogen: A substance, typically produced by bacteria, that induces fever.

Cytokine: Small proteins released by cells that have a specific effect on cell-to-cell communication and immune responses.

Hypothalamus: A region of the brain responsible for regulating various bodily functions, including temperature control.

Pyrogens are substances that cause an increase in body temperature by triggering the hypothalamus to elevate the body's set point. They can be exogenous, originating from outside the body such as bacteria, or endogenous, produced within the body like cytokines.

Inflammation: A biological response to harmful stimuli marked by redness, heat, swelling, and pain.

Cytokines: Small proteins released by cells that have a specific effect on interactions and communications between cells.

Hypothalamus: A region of the brain responsible for regulating body temperature among other functions.

Lipopolysaccharide (LPS) is a complex molecule found in the outer membrane of Gram-negative bacteria. It is a key component of the bacterial cell wall and plays a crucial role in various aspects of microbiology, immunology, and pathogenesis.

Endotoxin: Endotoxin is the lipid A portion of the lipopolysaccharide molecule, which is responsible for the toxic effects of LPS on the host immune system.

Gram-negative Bacteria: Gram-negative bacteria are a group of bacteria that have a thin peptidoglycan layer and an outer membrane composed of lipopolysaccharide, phospholipids, and proteins.

Toll-like Receptor 4 (TLR4): TLR4 is a pattern recognition receptor that binds to the lipid A component of lipopolysaccharide, triggering an inflammatory response in the host.

Cytokines are small proteins released by cells, especially those of the immune system, that have a specific effect on interactions and communications between cells. They play crucial roles in regulating immune responses and inflammation.

Interleukins: A group of cytokines that were first seen to be expressed by white blood cells (leukocytes).

Chemokines: A subset of cytokines responsible for inducing chemotaxis in nearby responsive cells.

Tumor Necrosis Factor (TNF): A type of cytokine involved in systemic inflammation and stimulation of the acute phase reaction.

Interleukin-1 (IL-1) is a pro-inflammatory cytokine produced by various cells, including macrophages, dendritic cells, and endothelial cells. It plays a crucial role in the body's inflammatory response and the regulation of immune functions.

Cytokine: Small proteins secreted by cells that act as signaling molecules to regulate immune responses and inflammatory processes.

Macrophage: A type of immune cell that engulfs and digests cellular debris, pathogens, and other harmful or foreign substances in the body.

Inflammation: The body's protective response to harmful stimuli, such as pathogens, damaged cells, or irritants, which involves the activation of the immune system.

Interleukin-6 (IL-6) is a multifunctional cytokine that plays a central role in the body's inflammatory response and fever regulation. It is produced by a variety of cells, including T cells, B cells, monocytes, and endothelial cells, and acts as a signaling molecule to coordinate the immune system's reaction to infection, injury, or other stressors.

Cytokine: Small proteins secreted by various cells, especially immune cells, that act as signaling molecules to regulate the immune response and inflammatory processes.

Acute Phase Response: A rapid systemic response initiated by the body to combat infection, injury, or other forms of stress, characterized by changes in the levels of various proteins and hormones.

Fever: An elevated body temperature above the normal range, often a symptom of infection or inflammation, that is regulated by the body's thermoregulatory mechanisms.

Tumor necrosis factor-α (TNF-α) is a pro-inflammatory cytokine produced primarily by activated macrophages and other immune cells. It plays a central role in the inflammatory response and the regulation of immune cells, making it a key mediator of both inflammation and fever.

Cytokine: Small signaling proteins secreted by various cells, especially immune cells, that regulate immune responses and inflammatory processes.

Macrophage: A type of immune cell that engulfs and digests cellular debris, pathogens, and other harmful or foreign materials in the body.

Inflammation: The body's immune response to injury, infection, or irritation, characterized by redness, swelling, heat, and pain.

The hypothalamus is a small region of the brain that plays a crucial role in maintaining homeostasis by regulating various autonomic processes, including body temperature and fever response.

Pyrogen: Substances that cause fever by stimulating the hypothalamus to raise body temperature.

Prostaglandin: A group of lipids involved in signaling processes such as inflammation and fever regulation.

Thermoregulation: The process by which an organism maintains its core internal temperature.

Phagocytic cells are a type of immune cell that play a crucial role in the body's defense against pathogens and foreign substances. These cells are capable of engulfing and digesting harmful microorganisms, cellular debris, and other unwanted materials, thereby protecting the host from infection and disease.

Macrophages: A type of phagocytic cell that resides in various tissues throughout the body, responsible for removing dead cells, cellular debris, and pathogens.

Neutrophils: A type of phagocytic cell that is the first line of defense against bacterial and fungal infections, rapidly responding to sites of inflammation and infection.

Dendritic Cells: A type of phagocytic cell that plays a key role in the adaptive immune response by presenting antigens to T cells and activating them.

Neutrophils are a type of white blood cell that play a crucial role in the innate immune response. They are the first responders to microbial infection and are highly active in phagocytosis.

Phagocytosis: The process by which cells, like neutrophils, engulf and digest pathogens.

Chemotaxis: The movement of an organism or cell toward or away from a chemical stimulus.

Granulocytes: A category of white blood cells characterized by the presence of granules in their cytoplasm; includes neutrophils, eosinophils, and basophils.

Macrophages are a type of large white blood cell that play a crucial role in the immune system's cellular defenses, inflammation and fever response, antigen presentation, and defense against bacterial infections. They are derived from monocytes and act as the first line of defense against pathogens and damaged cells.

Monocytes: Monocytes are a type of white blood cell that circulate in the bloodstream and can differentiate into macrophages when they migrate into tissues.

Phagocytosis: Phagocytosis is the process by which macrophages and other immune cells engulf and digest foreign particles, pathogens, and damaged or dead cells.

Antigen Presentation: Macrophages are a type of antigen-presenting cell that display pathogen-derived antigens on their surface, allowing them to activate T cells and initiate an adaptive immune response.

Neutrophils are a type of white blood cell that play a crucial role in the innate immune response. They are the first responders to microbial infection and are highly active in phagocytosis.

Phagocytosis: The process by which cells, like neutrophils, engulf and digest pathogens.

Chemotaxis: The movement of an organism or cell toward or away from a chemical stimulus.

Granulocytes: A category of white blood cells characterized by the presence of granules in their cytoplasm; includes neutrophils, eosinophils, and basophils.

PDGF, or Platelet-Derived Growth Factor, is a potent mitogen and chemoattractant that stimulates the growth, proliferation, and migration of various cell types, particularly fibroblasts, smooth muscle cells, and cells of mesenchymal origin. It plays a crucial role in the inflammatory response and wound healing processes.

Mitogen: A substance that stimulates a cell to begin the process of cell division and proliferation.

Chemoattractant: A chemical substance that attracts cells, such as leukocytes, towards the source of the chemical gradient.

Fibroblasts: Cells that synthesize the extracellular matrix and collagen, and are responsible for wound healing and scar tissue formation.

FGF, or Fibroblast Growth Factor, is a family of proteins that play a crucial role in regulating various cellular processes, including cell growth, differentiation, and survival. FGFs are involved in a wide range of physiological and pathological processes, particularly in the context of inflammation and fever.

Inflammation: A complex biological response of the body's immune system to various stimuli, such as pathogens, damaged cells, or irritants, characterized by redness, swelling, heat, and pain.

Fever: An elevation of the body's temperature above the normal range, often as a result of the body's immune response to an infection or other underlying condition.

Cytokines: Small signaling proteins secreted by various cells, including immune cells, that play a key role in regulating the inflammatory response and other physiological processes.

Cytokines are small proteins released by cells, especially those of the immune system, that have a specific effect on interactions and communications between cells. They play crucial roles in regulating immune responses and inflammation.

Interleukins: A group of cytokines that were first seen to be expressed by white blood cells (leukocytes).

Chemokines: A subset of cytokines responsible for inducing chemotaxis in nearby responsive cells.

Tumor Necrosis Factor (TNF): A type of cytokine involved in systemic inflammation and stimulation of the acute phase reaction.

TGF-β, or Transforming Growth Factor-beta, is a multifunctional cytokine that plays a crucial role in various physiological and pathological processes, including inflammation, immune regulation, and autoimmune disorders.

Cytokine: Small proteins secreted by cells that act as signaling molecules, mediating and regulating immunity, inflammation, and other cellular processes.

Inflammation: The body's protective response to harmful stimuli, such as pathogens, damaged cells, or irritants, characterized by redness, swelling, heat, and pain.

Autoimmune Disorder: A condition in which the immune system mistakenly attacks and damages the body's own healthy tissues and cells.

Reactive oxygen species (ROS) are highly reactive molecules containing oxygen, including superoxide, hydrogen peroxide, and hydroxyl radicals. They are generated as byproducts of normal cellular metabolism and play important roles in microbial growth and the inflammatory response.

Oxidative Stress: An imbalance between the production of ROS and the body's ability to detoxify them, leading to potential cellular damage.

Antioxidants: Molecules that can neutralize or scavenge ROS, helping to maintain redox balance and prevent oxidative stress.

Inflammation: The immune system's response to injury or infection, often involving the production of ROS to combat pathogens.

Elastase is a proteolytic enzyme that breaks down elastin, a key component of connective tissue. It is produced by certain bacteria and fungi as a virulence factor to facilitate tissue invasion.

Proteases: Enzymes that break down proteins into smaller peptides or amino acids.

Virulence Factors: Molecules produced by pathogens that contribute to the pathogenicity and promote infection.

Exotoxins: Toxic substances secreted by bacteria into their environment.

Collagenase is an enzyme that breaks down the protein collagen, which is a major structural component of connective tissues in the body. This enzyme plays a crucial role in the catabolism of lipids and proteins, as well as in the inflammatory response during injury or infection.

Collagen: A fibrous structural protein that provides strength and support to various tissues in the body, including skin, bone, cartilage, and tendons.

Connective Tissue: The tissue that provides support and structure to various organs and body parts, composed of cells and a matrix of fibers such as collagen and elastin.

Proteolytic Enzyme: An enzyme that catalyzes the breakdown of proteins into smaller peptides or amino acids.

Sepsis is a life-threatening condition that arises when the body's response to an infection spirals out of control, triggering widespread inflammation that can lead to organ dysfunction and even death. It is a critical medical emergency that requires prompt recognition and treatment to prevent severe complications.

Bacteremia: The presence of bacteria in the bloodstream, which can lead to the development of sepsis.

Systemic Inflammatory Response Syndrome (SIRS): A condition characterized by a widespread inflammatory response, often a precursor to sepsis.

Septic Shock: A severe form of sepsis that involves low blood pressure and organ dysfunction, requiring immediate medical intervention.

Systemic Inflammatory Response Syndrome (SIRS) is a clinical condition characterized by a widespread inflammatory response to a variety of severe clinical insults, including infection, trauma, burns, and other critical illnesses. It is a dysregulated immune response that can lead to organ dysfunction and, if uncontrolled, progress to life-threatening sepsis.

Inflammation: The body's protective immune response to harmful stimuli, such as pathogens, damaged cells, or irritants, which aims to remove the initial cause of cell injury, clear out necrotic cells and tissues damaged from the original insult, and initiate the healing process.

Fever: An elevation of the body's temperature above the normal range, often as a result of the body's inflammatory response to an infection or other illness.

Sepsis: A life-threatening condition that arises when the body's response to an infection triggers a chain reaction, leading to widespread inflammation, tissue damage, and organ failure.

Chronic inflammation is a prolonged inflammatory response that can last for months or years, often due to persistent infection, autoimmune response, or prolonged exposure to harmful agents. It involves the continuous presence of immune cells and can lead to tissue damage and disease.

Acute Inflammation: A rapid immune response to injury or infection characterized by redness, heat, swelling, and pain.

Cytokines: Signaling proteins released by cells that mediate and regulate immunity and inflammation.

Fibrosis: The thickening and scarring of connective tissue usually as a result of injury or long-term inflammation.

Atherosclerosis is a chronic inflammatory condition characterized by the buildup of plaque, composed of cholesterol, fatty substances, cellular waste products, calcium, and other materials, within the inner lining of the arteries. This gradual accumulation of plaque can restrict blood flow and increase the risk of heart attack, stroke, and other cardiovascular events.

Inflammation: A complex biological response of the body's immune system to various stimuli, such as pathogens, damaged cells, or irritants, which serves to eliminate the initial cause of cell injury, clear out necrotic cells and tissues, and initiate the healing process.

Fever: An elevation of the body's temperature above the normal range, often as a result of the body's immune response to an infection or other inflammatory condition.

Cholesterol: A waxy, fat-like substance found in the body's cells, used to produce hormones, vitamin D, and other substances necessary for proper bodily function. High levels of certain types of cholesterol can contribute to the development of atherosclerosis.

Rheumatoid arthritis is a chronic autoimmune disorder characterized by inflammation of the joints, leading to pain and deformity. It occurs when the immune system mistakenly attacks the body's own tissues.

Autoimmune Disorder: A condition in which the immune system attacks the body's own tissues.

Synovitis: Inflammation of the synovial membrane that lines joints.

Rheumatoid Factor (RF): An autoantibody found in the blood that is often elevated in patients with rheumatoid arthritis.

Inflammatory bowel disease (IBD) is a group of chronic, inflammatory conditions that affect the gastrointestinal tract, primarily the small and large intestines. IBD is characterized by an abnormal immune response that leads to persistent inflammation and damage to the digestive system.

Crohn's Disease: A type of IBD that can affect any part of the digestive tract, causing inflammation, ulcers, and thickening of the intestinal wall.

Ulcerative Colitis: A type of IBD that specifically affects the large intestine (colon) and rectum, causing inflammation and the development of ulcers.

Gut Microbiome: The diverse community of microorganisms that reside in the human digestive tract and play a crucial role in maintaining intestinal health and immune function.

Crohn's disease is a type of inflammatory bowel disease (IBD) that causes chronic inflammation and irritation in the digestive tract. It can affect any part of the gastrointestinal system, from the mouth to the anus, but it most commonly occurs in the end of the small intestine (the ileum) and the beginning of the colon.

Inflammatory Bowel Disease (IBD): A group of chronic, inflammatory conditions that affect the gastrointestinal tract, including Crohn's disease and ulcerative colitis.

Granuloma: A collection of immune cells that form a nodule in response to inflammation, a characteristic feature of Crohn's disease.

Fistula: An abnormal connection or passageway that develops between two organs or between an organ and the skin, a common complication of Crohn's disease.

Ulcerative colitis is a chronic inflammatory bowel disease that causes inflammation and ulcers in the lining of the large intestine (colon) and rectum. It is characterized by periods of flare-ups and remission, and can significantly impact a person's quality of life if not properly managed.

Inflammatory Bowel Disease (IBD): A group of chronic conditions that involve inflammation of the gastrointestinal tract, including ulcerative colitis and Crohn's disease.

Colon: The largest part of the large intestine, responsible for absorbing water and electrolytes from indigestible food matter.

Inflammation: The body's immune response to irritation, injury, or infection, characterized by redness, swelling, heat, and pain.

Acute inflammation is the immediate and early response of the body to harmful stimuli like pathogens, damaged cells, or irritants. It aims to eliminate the initial cause of cell injury, clear out necrotic cells and tissues, and establish a repair process.

Chronic Inflammation: A prolonged inflammatory response lasting for weeks or months due to persistent irritants.

Histamine: A chemical mediator released by mast cells that increases vascular permeability during inflammation.

Neutrophils: A type of white blood cell that is one of the first responders to sites of infection or injury.

The acute phase response is a rapid, systemic, and nonspecific reaction of the body to various forms of inflammation, infection, tissue damage, or other stressors. It is a coordinated series of physiological and biochemical changes that occur to help the body combat the underlying cause of the disturbance and restore homeostasis.

Cytokines: Small signaling proteins secreted by various cells, including immune cells, that play a crucial role in initiating and regulating the acute phase response.

Acute-Phase Proteins: Proteins synthesized by the liver in response to cytokine signals during the acute phase response, which help combat infection, neutralize pathogens, and promote tissue repair.

Inflammation: The body's protective immune response to harmful stimuli, such as pathogens, damaged cells, or irritants, which triggers the acute phase response.

Acute inflammation is the immediate and early response of the body to harmful stimuli like pathogens, damaged cells, or irritants. It aims to eliminate the initial cause of cell injury, clear out necrotic cells and tissues, and establish a repair process.

Chronic Inflammation: A prolonged inflammatory response lasting for weeks or months due to persistent irritants.

Histamine: A chemical mediator released by mast cells that increases vascular permeability during inflammation.

Neutrophils: A type of white blood cell that is one of the first responders to sites of infection or injury.

Lymphocytes are a type of white blood cell that play a crucial role in the body's immune response. They are responsible for recognizing and responding to foreign invaders, such as bacteria, viruses, and other pathogens, as well as abnormal cells within the body.

T Cells: A type of lymphocyte that matures in the thymus gland and is responsible for cell-mediated immunity, directly attacking infected or cancerous cells.

B Cells: A type of lymphocyte that matures in the bone marrow and is responsible for humoral immunity, producing antibodies to neutralize and eliminate pathogens.

Natural Killer Cells: A type of lymphocyte that can directly kill infected or cancerous cells without the need for prior activation or recognition.

Plasma cells are differentiated B lymphocytes that produce and secrete large quantities of antibodies. They play a critical role in the humoral immune response by targeting specific antigens.

B Lymphocytes: White blood cells that mature in the bone marrow and are part of the adaptive immune system.

Antibodies: Proteins produced by plasma cells that specifically bind to antigens to neutralize or mark them for destruction.

Humoral Immunity: Aspect of immunity mediated by macromolecules found in extracellular fluids such as antibodies, complement proteins, and certain antimicrobial peptides.

Fibrosis is the formation of excess fibrous connective tissue in an organ or tissue, often as a result of injury, inflammation, or disease. It is a pathological process that can impair the normal function of the affected organ or tissue.

Collagen: The main structural protein found in the extracellular matrix of connective tissues, such as skin, bone, and cartilage. Excess collagen deposition is a hallmark of fibrosis.

Myofibroblasts: Specialized cells that play a crucial role in the development of fibrosis by secreting excessive amounts of extracellular matrix components, particularly collagen.

Tissue Remodeling: The process of reorganizing and replacing damaged or diseased tissue with new, often less functional, fibrous tissue, leading to the development of fibrosis.

Cirrhosis is a chronic liver disease characterized by the replacement of normal liver tissue with non-functioning scar tissue. This condition can lead to a variety of complications and is often associated with inflammation and viral infections of the gastrointestinal tract.

Fibrosis: The excessive accumulation of extracellular matrix proteins, such as collagen, which can lead to the formation of scar tissue in the liver.

Portal Hypertension: An increase in the blood pressure within the portal venous system, which can result from the development of cirrhosis and lead to complications like variceal bleeding.

Hepatic Encephalopathy: A neurological condition that can develop in individuals with cirrhosis, caused by the buildup of toxins in the blood that the liver is unable to properly metabolize.

Pulmonary fibrosis is a chronic, progressive lung disease characterized by the formation of scar tissue within the lungs. This scarring impairs the lungs' ability to function properly, leading to breathing difficulties and reduced oxygen supply to the body.

Inflammation: The immune system's response to injury or infection, marked by redness, swelling, heat, and pain. Inflammation is a key driver of pulmonary fibrosis.

Fibroblasts: Cells that play a crucial role in the development of pulmonary fibrosis by producing excessive amounts of collagen and other extracellular matrix proteins, leading to the formation of scar tissue.

Idiopathic Pulmonary Fibrosis (IPF): A specific type of pulmonary fibrosis with an unknown cause, characterized by a progressive and irreversible scarring of the lungs.

Inflammaging is the chronic, low-grade inflammation that occurs with aging, characterized by the persistent activation of the immune system and the increased production of inflammatory mediators. This process contributes to the development and progression of various age-related diseases.

Senescence: The gradual deterioration of cellular function and the loss of the ability to divide, leading to cellular aging.

Oxidative Stress: An imbalance between the production of free radicals and the body\'s ability to neutralize them, leading to cellular damage.

Immunosenescence: The age-related decline in the function and responsiveness of the immune system.

Osteoarthritis is a degenerative joint disease characterized by the breakdown and eventual loss of the cartilage that cushions the ends of the bones where they meet to form a joint. This leads to the bones rubbing together, causing pain, swelling, and loss of motion in the affected joint.

Cartilage: A firm, flexible connective tissue that covers the ends of bones in a joint, allowing for smooth and pain-free movement.

Inflammation: The body's immune response to injury or infection, marked by redness, swelling, heat, and pain.

Synovial Fluid: A thick, lubricating fluid produced by the synovial membrane that helps reduce friction and wear in the joint.

Sarcopenia is the age-related loss of skeletal muscle mass and strength, leading to decreased physical function and mobility. It is a key factor in the development of frailty and is closely linked to the processes of inflammation and fever.

Cachexia: A severe form of muscle wasting associated with chronic diseases, characterized by unintentional weight loss, muscle atrophy, and weakness.

Myokines: Cytokines and other signaling molecules secreted by skeletal muscle cells that have local and systemic effects, influencing processes such as inflammation and metabolism.

Inflammaging: The chronic, low-grade inflammation that occurs with aging, which contributes to the development of age-related diseases and sarcopenia.

Histamine is a biogenic amine that plays a crucial role in various physiological and pathological processes within the human body. It is primarily involved in the regulation of immune responses, inflammation, and hypersensitivity reactions.

Mast Cells: Immune cells that contain histamine-filled granules and release histamine in response to allergens or other stimuli, triggering inflammatory and hypersensitivity reactions.

Histamine Receptors: Cell surface receptors that bind to histamine, mediating its diverse effects on the body, including vasodilation, increased vascular permeability, and stimulation of smooth muscle contraction.

Histamine Intolerance: A condition where the body's ability to break down and metabolize histamine is impaired, leading to an accumulation of histamine and the development of various symptoms.

Vasodilation is the widening of blood vessels resulting from relaxation of the muscular walls of the vessels. It increases blood flow to tissues and helps in thermoregulation and immune response.

Inflammation: A biological response to harmful stimuli, characterized by redness, swelling, heat, pain, and loss of function.

Nitric oxide: A signaling molecule that promotes vasodilation by relaxing smooth muscles in blood vessels.

Endothelial cells: Cells lining the interior surface of blood vessels, playing a crucial role in vascular functions including vasodilation.

The complement system is a group of proteins that enhance the ability of antibodies and phagocytic cells to clear pathogens from an organism. It forms part of the innate immune response and also helps bridge innate and adaptive immunity.

Opsonization: The process by which pathogens are marked for ingestion and destruction by phagocytes.

Membrane Attack Complex (MAC): A structure formed on the surface of pathogenic bacterial cells as a result of the activation of the host's complement system.

Phagocytosis: The process by which cells ingest and destroy foreign particles or microorganisms.

The leukocyte adhesion cascade is a multi-step process that facilitates the recruitment and migration of white blood cells (leukocytes) from the bloodstream to sites of inflammation or infection. This cascade is a crucial component of the body's immune response and inflammation.

Leukocytes: White blood cells that play a central role in the immune system, responsible for defending the body against pathogens and disease.

Endothelium: The thin layer of cells that line the interior surface of blood vessels, lymphatic vessels, and the heart.

Chemokines: Small cytokine proteins that attract and activate specific types of leukocytes to sites of inflammation or infection.

Resolution of inflammation is the process by which the body actively terminates and restores homeostasis after an inflammatory response. It involves the coordination of various cellular and molecular mechanisms to return the affected tissue to its normal state and function.

Inflammation: Inflammation is the body's protective immune response to harmful stimuli, such as pathogens, damaged cells, or irritants, which aims to eliminate the initial cause of cell injury, clear out necrotic cells and tissues, and initiate the healing process.

Homeostasis: Homeostasis is the process of maintaining a stable, relatively constant internal environment in a living organism despite changes in external conditions.

Proresolution Mediators: Proresolution mediators are endogenous lipid and protein signaling molecules that actively promote the resolution of inflammation by inhibiting the inflammatory response and initiating tissue repair.