Inflammation PDF

# Inflammation ## Inflammation is the response that vascularized tissues have against tissue injury/damage. - This response involves bringing cells & their mole-cules to areas of injury so as to get rid of the harmful agent. - This response is initiated by the cells of the host which detect the st...

# Inflammation ## Inflammation is the response that vascularized tissues have against tissue injury/damage. - This response involves bringing cells & their mole-cules to areas of injury so as to get rid of the harmful agent. - This response is initiated by the cells of the host which detect the stimulus emitted from the area of injury. - Inflammatory response study/examines as to how the response is initiated. - However, in some situations, the experts/consequences of the inflammation are the main causes for a disease. - The occurance of inflammation is usually presented by 5 **cardinal signs.** - Heat - also known as external manifestation. - Redness - Swelling - Pain - Loss of Function - These signs are what most might perceive to be the symptoms that might lead to a disease. - Therefore, most often inflammatory terms may lead to the distal progression of a certain disease. ## Inflammatory response to infection → Local tissue damage → Pain → Tissue Damage - However, most of the time, these expert of tissue damage by themselves. - Sometimes, this inflammatory response might get misdirected thus aplecting rather healthy cells instead of infection cells. - i.e., autoimmune diseases. ## Inflammatory response can cause chronic diseases such as rheumatoid arthritis, atherosclerosis, & chronic bites & toxins. - If the harmful consequences of inflammation are not caught earlic on, it might lead to a more disastrous outcome. - Due to this, it is referred to as "Silent Killer". ## Causes of inflammation 1. **Infections**: These might be caused by microbes, virus, bacteria, toxins etc. 2. **Tissue necrosis**: "Necrosis" is the unprogrammed cell death. Tissue necrosis might cause inflammation by 3 ways: - Ischemia: Reduced blood supply to a certain tissue → hypoxia → Necrosis. - Trauma: Physical trauma might also lead to Necrosis. - Physical & Chemical Injury: For example chemical burns and severe frostbite could all feed to necrosis. 3. **Foreign bodies**: These could either be **exogenous** or **endogenous** - Exogenous foreign bodies: Splinters, dirt, sutures. - Endogenous foreign bodies: Crystals like urate crystals (gout) and cholesterol crystals. (Atherosclerosis). 4. **Immune reactions**: It is also called hypersensitivity as it is the body's response against damaged own tissue. It could be due to allergies, auto immune diseases etc. ## Steps of inflammatory response "5-R-I" - Recognition of injurious agent - Recruitment of leukocytes. - Removal of the agent - Regulation (control) of the response - Repairing (resolution) of the damaged site. ## Types of Inflammation - Acute inflammation - Chronic inflammation ## 1. Acute Inflammations. - This is the initial & rapid response to infections and tissue damage. - It develops within minutes or sometimes hours. - For example; rash due to mosquito bite - Cardinal sign: Pain / itching, heal, swelling, & redness. - It also clears / heals after a short period of time. It's in several hours or a few days - For example; a fever due to cold might last for a couple of hours & then disappear. - Cardinal signs: Heat, redness, pain (headache). ## AI has 3 major components: - **Dilation of small blood vessels** - This intur leads to ↑ blood flow (hyperemia) to the site of injury. - **↑ permeability of the microvasculature** - This enables plasma proteins, & leukocytes to leave the circulation & head towards the site of injury. - **Movement (emigration) of leukocytes** - These move out of the circulation to the site of injury and accumulate there. - After accumulating, they activate & initiate the inflammatory response ## Reaction of vessels to A.I - Basically, vessels dilate to cause hyperemia and then ↑ permeability so as to allow proteins & leukocytes to exit the circulation & go to the injured area. ## 2 words to know are Exudate & Transudate - **Exudate**: Is the fluild outside the vessels (extra vascular fluid) that has a ↑ protein conc, & has cellular debris. - Its presence means that perniability of vessels has ↑ during an inflammatory run.. - **Transudate**: Is the fluid outside the vessels (extra vascular fluid) with ↑ protein conc. & little/no cellular material (debris) & 1/ specific gravity. ## So transudate occurs as a result of an osmotic/hydrostatic imbalance that occurs with normal vascular permeability. ## Examples: - **Edema**: Could either be an exudate or transudate. It essentially means fluid in the interstion / servous cavitics. - **Pus**: Is an exudate rich in leukocytes, dead cells debris, & microbes. ## Summary ## Role of vasculature to A.I - **Vasodilation** which is induced by mediators such as histamine. They cause edema & stasis. - **↑ vascular permeability** which is induced by mediators like histamine, bradkining, leukotrienes, etc. These mediators produce gaps bin endothelial cells by; - Direct endothelial injury - Leukocyte-induced endothelial injury - ↑ passage of fluids through the endothelium & leukocytes (the mediators of host defence) enter site of infection/tissue damage. ↑ vascular permeability allows this. - However, ↑ / Exudation results to edema. - **Lymphatic vessels & lymph nodes** then take the excess fluid back to the circulation. However, if they get over powered, it might result to more inflammation & cardinal signs might include **pain, swelling, redness** externally where lymph vessels / lymph nodes pass.