Week 1 - Inflammation Flashcards
What are the main signs of inflammation?
Calor (Heat), Dolor (pain), Rubor (redness), Tumor (swelling), Functio Laesa (temporary loss of function due to above)
Explain heat during inflammation
Heat occurs when cytokines (prostaglandins) vasodilate and bring blood to the area.
Explain pain during inflammation
Pain occurs when specific cytokines (prostaglandins) are released in the complement system which sensitise nerve endings sending pain signals to the thalamus where it’s processed and send to somatosensory cortex which is responsible for the physical sensation of pain and helps localize and characterize the pain.
Explain redness in inflammation
Redness occurs at the site due to vasodilation and increased blood flow to the area.
Explain swelling during inflammation
Swelling occurs due to an increase in vascular permeability, allowing fluids, white blood cells and other inflammatory mediators to escape the bloodstream into the surrounding tissue.
Explain temporary loss of function during inflammation
This sometimes occurs due to the other 4 symptoms (pain, swelling, redness, heat).
What often initiates the inflammatory response?
The inflammatory response generally begins with harmful stimuli like pathogens including bacteria, viruses, which lead to infection.
Toxins and Trauma (ankle sprain)
Exercise-induced (muscle soreness after intense workout as a form of inflammation
What are the external factors that can trigger inflammation?
External factors include non-microbial elements like allergens, irritants, and toxic compounds, as well as microbial elements such as virulence factors and PAMPs (pathogen-associated molecular patterns).
What are PAMPs and their role in inflammation?
PAMPs (pathogen-associated molecular patterns) are microbial factors recognized by the immune system, triggering inflammation.
What are internal factors that can initiate inflammation?
Internal factors include DAMPs (damage-associated molecular patterns) that are released from cell damage.
What is a virulence factor?
Virulence factors are apart of the external microbial factors which help pathogens colonise tissues and cause infection
A virulence factor is a pathogens ability to infect someone
How do leukocytes (WBC) contribute to the inflammatory response?
Leukocytes, including granulocytes and agranulocytes, play key roles in PAMPs and DAMPS.
Pattern Recognition Receptors (PRRs)
Receptors on leukocytes that detect PAMPs & DAMPs and spark inflammatory response. They are non specific, have no memory and are quick to respond: minutes - hours
Types of Leukocytes
Granulocytes: Including neutrophils, eosinophils, basophils, and mast cells.
Agranulocytes: Including lymphocytes and monocytes (macrophages/dendritic cells).
Leukocytes initial responders
Macrophages, mast cells and dendritic cells
Inflammatory mediators released by mast cells
Histamine, serotonin, cytokines & eicosanoids (prostaglandins & leukotrienes)
Inflammatory mediators and actions - Macrophage
Phagocytose (devour) invading pathogens and cells damaged. Also efferocytose apoptitic neutrophils.
Release Cytokines, Nitric Oxide (NO) and Reactive Oxygen Species (ROS) for microbial killing and signalling, Prostaglandins and leukotrines, enzymes, growth factors (TGF-b)
Inflammatory mediator - Neutrophil recruitment and action
Attracted to the site, extravasate through cell wall of blood vessel to site of injury, Phagocytose (devour) invading pathogens and damaged cells, then self-destruct (apoptosis), they are then efferocytosis is performed by macrophages to clear apoptitic cells.
Release mediators - ROS, enzymes, cytokines and Neutrophil Extracellular Traps (NETs)
What is apoptosis?
The process of programmed cell death. It is used by cells to eliminate unwanted cells. They phagocytose the unwanted cell and then perform apoptosis.
Complement system
Activated in the presence of pathogens
Bunch of proteins that attach themselves to pathogens and attract leukocytes through opsonization (tag foreign pathogens for elimination process)
What do dendritic cells do?
They phagocytose pathogens and bacteria while also giving little bits to T lymphocytes which activates the adaptive immune system (kicks in after a few days)
How does a clot at the wound site appear and why does this occur?
Platelets and clotting factors in the blood arrive at the site to build a framework for tissue repair.
This occurs to stop bleeding and prevents pathogens from entering blood stream.
How does the tissue repair phase happen?
Macrophages around the area clean up dead/dying cells to make room for new cells. Then growth factors promotes angiogenesis (new blood vessels that are temporary) to the wound area.
Next Fibroblasts synthesise collagen to help with wound healing.
