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急性炎症 I: 炎症反应
急性炎症是组织损伤或感染后发生的一种快速、短暂的生理反应，旨在清除有害因素并启动组织修复。这一受到严格调控的过程通常持续数分钟至数天，并由微生物入侵、物理创伤或化学损伤等因素触发。
识别与炎症介质释放
当驻留免疫细胞，例如肥大细胞、巨噬细胞和树突状细胞，通过模式识别受体，即 PRR，识别损伤相关分子…
急性炎症是一种短期反应，持续数分钟至数天，由感染、创伤或化学性损伤引发，可导致坏死。
该过程始于机体检测到有害刺激时，激活肥大细胞、巨噬细胞和树突状细胞等常驻免疫细胞，这些细胞通过模式识别受体识别病原体相关分子模式和损伤相关分子模式。
这些细胞一旦被激活，便会释放组胺和前列腺素等炎性介质，导致血管扩张和局部血流量增加，从而引起红斑。
这些血管变化会产生炎症的典型体征——红斑、水肿和发热。
肿胀和炎症介质（如前列腺素和缓激肽）会敏化局部神经，引发疼痛。
肿瘤坏死因子（TNF）和白细胞介素-1（IL-1）等细胞因子可激活内皮细胞表达选择素和黏附分子，从而介导白细胞在受损部位的滚动、黏附及穿出血管。
白细胞随后会清除病原体，还可能清除碎片，从而减轻炎症并促进愈合。
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Q1: What triggers the acute inflammatory response in the body?
Acute inflammation is triggered by infection, trauma, or chemical injury that causes tissue damage. The body detects harmful stimuli through resident immune cells like mast cells, macrophages, and dendritic cells, which recognize pathogen-associated and damage-associated molecular patterns via pattern-recognition receptors. This recognition activates the inflammatory cascade.
Q2: How do inflammatory mediators cause the classic signs of inflammation?
Activated immune cells release inflammatory mediators such as histamine and prostaglandins, which cause vasodilation and increased blood flow to the injured site, producing erythema and heat. Simultaneously, increased vascular permeability allows fluid to move into surrounding tissue, causing edema. These mediators also sensitize local nerves, generating pain.
Q3: What role do cytokines play in leukocyte recruitment during inflammation?
Cytokines such as TNF and IL-1 activate the endothelium to express selectins and adhesion molecules on blood vessel walls. These molecules enable leukocytes to roll along the vessel surface, adhere firmly, and transmigrate through the endothelium into inflamed tissue via diapedesis, facilitating immune cell delivery to the injury site.
Q4: How long does acute inflammation typically last?
Acute inflammation is a short-term response that lasts from minutes to several days. This tightly regulated process is designed to eliminate harmful agents and initiate tissue repair. Once pathogens are cleared and debris is removed, the inflammatory response resolves and healing begins.
Q5: What functions do leukocytes perform once they reach inflamed tissue?
Leukocytes, particularly neutrophils, perform critical effector functions including phagocytosis of pathogens, release of antimicrobial enzymes, and clearance of necrotic debris. These actions eliminate harmful agents and remove damaged tissue, contributing to resolution of inflammation and promotion of tissue repair and healing.
Q6: How does vasodilation contribute to the inflammatory response?
Vasodilation of local arterioles increases blood flow to the injured area, delivering immune cells and nutrients while producing erythema and heat. Reduced flow velocity due to plasma leakage into tissue facilitates firm adhesion and transmigration of leukocytes across the endothelium, enabling immune cells to reach the inflammation site.
Q7: What happens after acute inflammation resolves?
Once leukocytes eliminate pathogens and clear debris, inflammation reduces and tissue repair is promoted. Understanding how acute inflammation progresses to local and systemic effects helps explain the transition from the acute phase to healing. Students can explore acute inflammation iii local and systemic effects for comprehensive coverage of inflammation's broader impact.