《微生物学》课程PPT课件讲稿（英文版）Lecture 5 Medical Microbiology

Constitutive Defenses Barriers to entry See Schaechter text table 6.1 Mucous membranes--covered by protective layer of mucus Mechanical and chemical barrier that allows proper functioning Cross-linked gel structure composed of glycoprotein subunits BIOL 533 Lecture 5

BIOL 533 2 Lecture 5 Constitutive Defenses • Barriers to entry – See Schaechter text, Table 6.1 • Mucous membranes—covered by protective layer of mucus – Mechanical and chemical barrier that allows proper functioning • Cross-linked gel structure composed of glycoprotein subunits

Mucus membranes Entraps particles and prevents them from getting to mucus membrane Hydrophilic: allows passage of a number of bodily substances Antimicrobial substances(lysozyme and peroxidase) Can withstand substantial weight but still be propelled by cilia BIOL 533 Lecture 5

BIOL 533 3 Lecture 5 Mucus Membranes • Entraps particles and prevents them from getting to mucus membrane – Hydrophilic: allows passage of a number of bodily substances • Antimicrobial substances (lysozyme and peroxidase) • Can withstand substantial weight, but still be propelled by cilia

Defenses of Deep Tissues带 Role of constitutive defenses List of humoral mediators of constitutive defenses(See Schaechter text, Table 6.2) BIOL 533 Lecture 5

BIOL 533 4 Lecture 5 Defenses of Deep Tissues • Role of constitutive defenses – List of humoral mediators of constitutive defenses (See Schaechter text, Table 6.2)

Defenses of Deep Tissues带 Role of constitutive defenses contd Inflammatory response does not require previous contact with microorganism Elicited by complex effectors many of which are complement system Normally at basal level and must be further increased by presence of microorganisms in tissues Most important consequence of activity is phagocyte attraction BIOL 533 Lecture 5

BIOL 533 5 Lecture 5 Defenses of Deep Tissues • Role of constitutive defenses, cont’d. – Inflammatory response does not require previous contact with microorganism – Elicited by complex effectors, many of which are complement system • Normally at basal level and must be further increased by presence of microorganisms in tissues – Most important consequence of activity is phagocyte attraction

Defenses of Deep Tissues带 Interaction of constitutive(inflammatory response) and inducible defenses (immune response) Inducible response cannot occur without constitutive mediators Mediators lead to induction of immune response and also defend against microbial invader BIOL 533 Lecture 5

BIOL 533 6 Lecture 5 Defenses of Deep Tissues • Interaction of constitutive (inflammatory response) and inducible defenses (immune response) – Inducible response cannot occur without constitutive mediators • Mediators lead to induction of immune response and also defend against microbial invader

Inflammation General aspects Reaction to tissue injury-manifested by pain swelling, heat, and throbbing of location Location appears red and shiny hot and painful to touch as a result of changes in local blood vessels and lymphatics Tissues may return to normal or scarring may result BIOL 533 7 Lecture 5

BIOL 533 7 Lecture 5 Inflammation • General aspects – Reaction to tissue injury—manifested by pain, swelling, heat, and throbbing of location – Location appears red and shiny, hot and painful to touch as a result of changes in local blood vessels and lymphatics – Tissues may return to normal or scarring may result

Inflammation Tissues may return to normal or scarring may result depends on extent of damage done By injury By infecting microbes By inflammatory response BIOL 533 Lecture 5

BIOL 533 8 Lecture 5 Inflammation • Tissues may return to normal or scarring may result; depends on extent of damage done: – By injury – By infecting microbes – By inflammatory response

Inflammation Description of changes Blood supply increases to affected part due to vasodilation Capillaries become more permeable, allowing fluid and large molecules to move into tissues Consequence of inflammation pH of inflamed tissues lowered Production of lactic acid -antimicrobial BIOL 533 Lecture 5

BIOL 533 9 Lecture 5 Inflammation • Description of changes – Blood supply increases to affected part due to vasodilation – Capillaries become more permeable, allowing fluid and large molecules to move into tissues – Consequence of inflammation • pH of inflamed tissues lowered – Production of lactic acid—antimicrobial

Inflammation Molecular basis of inflammatory response and acute phase response Inflammatory response starts with activation of complement or of blood-clotting cascade Complement and clotting are interactive Either can set off the other Normally, clotting is seen when acute inflammatory response is severe BIOL 533 Lecture 5

BIOL 533 10 Lecture 5 Inflammation • Molecular basis of inflammatory response and acute phase response – Inflammatory response starts with activation of complement or of blood-clotting cascade • Complement and clotting are interactive • Either can set off the other • Normally, clotting is seen when acute inflammatory response is severe

Molecular basis Inflammatory response leads to production and release of a number of chemical effectors of inflammation responsible for vascular permeability vasodilation, and pain Histamine Kinin Leukotrienes and prostaglandins BIOL 533 Lecture 5

BIOL 533 11 Lecture 5 Molecular Basis • Inflammatory response leads to production and release of a number of chemical effectors of inflammation responsible for vascular permeability, vasodilation, and pain – Histamine – Kinin – Leukotrienes and prostaglandins