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급성 염증 I: 염증 반응
급성 염증은 조직 손상이나 감염에 대한 빠르고 단명한 생리학적 반응으로, 유해 물질을 제거하고 수리를 시작하기 위해 설계되었습니다. 이 엄격하게 조절된 과정은 보통 몇 분에서 며칠까지 지속되며, 미생물 침입, 신체적 외상, 화학적 손상 등의 요인에 의해 촉발됩니다.
인정…
급성 염증은 몇 분에서 며칠까지 지속되는 단기 반응으로, 감염, 외상 또는 화학적 손상에 의해 괴사를 초래합니다.
이 과정은 신체가 유해 자극을 감지하면서 시작되며, 비만세포, 대식세포, 수지상세포와 같은 상주 면역세포가 활성화되어, 패턴 인식 수용체를 통해 병원체 관련 및 손상 관련 분자 패턴을 감지합니다.
활성화된 이 세포들은 히스타민과 프로스타글란딘과 같은 염증 매개체를 분비하여 혈관 확장과 혈류 증가를 일으켜 홍반을 유발합니다.
이러한 혈관 변화는 홍반, 부종, 열과 같은 전형적인 염증 징후를 유발합니다.
프로스타글란딘과 브라디키닌과 같은 염증 매개체가 국소 신경을 감작시켜 통증을 유발합니다.
TNF와 IL-1과 같은 사이토카인은 내피를 활성화하여 셀렉틴과 부착 분자를 발현시키고, 이를 통해 백혈구가 영향을 받은 부위로 굴러가고, 접착하며, 이완 형태로 이동할 수 있게 합니다.
백혈구는 병원체를 제거하고 이물질을 제거하여 염증을 줄이고 치유를 촉진합니다.
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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.