UNC-Chapel Hill MCRO 251 - Exam 2 MCRO (49 pages)

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Exam 2 MCRO



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Exam 2 MCRO

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Pages:
49
School:
University of North Carolina at Chapel Hill
Course:
Mcro 251 - Introductory Medical Microbiology
Introductory Medical Microbiology Documents
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Assigned animations Chapter 14 ALL Antiviral activity of Interferon Presence of viral material in cell signals to produce interferon Interferon leaves cell attaches to receptors of cells nearby same type Cell now infected by virus and release more viruses to infect nearby cell Nearby cell has interferon can make enzyme to degrade mRNA and prevent protein synthesis o Virus can enter cell but viral replication prevented Activation of Complement Complement serum protein o Activates inflammation causes cell lysis and participates in opsonization C1 C9 major component o Name by order discover not which they function Compliment cascade activated by classical pathway or alternative Classical pathway o C1 activated when binds to antigen antibody complex o C1 cleave c2 into c2 a b o C4 into c4a b o C2b andc4b protease C3 convertase cleaves c3 into c3 a b Alternative pathway o Atigens react with C3b o C3a b are formed from C3 w o activation destroyed o C3b reacts with proteins factor b and factor d and properdin form C3 convertase Both pathways follow same sequence after cleavge of C3 C3 stimulates inflammation Microorganism with C3b bound to surface are more susceptible of phagocytosis Coding of bacteria to make them more susceptible to phagocytosis opsonization C5 a enhances inflammation C5b reacts with other to form membrane attack causes hole and cell to lyse Functions of Complement C3a inflammation o Induce change to walls of vessel C5a attraction of neutrophils o Induces chemotactic migration of phagocyte to site of complement activation C3b opsonization o Binds to microbial cells making them more susceptible to phagocytosis C5b C6 C7 C8 C9 cell lysis o Makes hole in cell membrane lysis Toll like receptors to give an overview above your paygrade info Phagocytosis Attracted by chemical product of organism 1 Phagocyte attaches to microorganism from surface receptors antibodies lipopolysaccharide and complement receptors Microorganism engulfed by phagocyte into vacuum phagosome o fuses with lysosome releases digestive enzymes ito phagosome phagolysosome inside microorganisms are killed and digested digested contents are eliminated via exocytosis Lysosomes Lysosomes membrane bound vesicles that can contain hydrolytic enzyme Hydrolytic enzymes degrade proteins lipids nucleic acids and carbs o Formed in ER Enzymes transported to golgi app via transport vesicles When viruses bacteria are ingested lysosome fuses with phagosome delivers hydrolytic enzymes Lysosomes also fused with organelles like old mitochondria helps with destruction and recycling of structures The Inflammatory process Response in a non specific defense against tissue damage Begins when chemical singals activate endothelial cells of nearby capillaries Integrins attach to endothelial cells cause neutrophils to stick and stop roling o Accumulation of neutrophils along walls of capillary margination Histamine causes vasodilation and an opening btw junction of endothelial wall I The Immune System There are two basic arms of the immune system A Acquired Immunity specific immune system 1 Also called cognate immunity because it is a learned response We are exposed to the specific microbe and the acquired immune system will learn to recognize it and respond to it a Example we have measles when we are children but our immune system learns to identify that specific pathogen and is ready for subsequent exposures b It has acquired the ability to recognize that pathogen c Takes time to be initiated d Knows and recognizes specific pathways 1 Knows the antigen it is fighting off e How quickly can one bacteria become 16 mill 1 8 hours 2 If we have to wait a week we just use the innate immune system 2 Very specific but it takes time to become activated not just hours but days a Needs to build an army to fight off infection B Innate immunity natural immune system 2 1 It is the first line of host defense typically works by blocking the invasion or the invasive properties of the microbe or its replication 2 You acquire it at birth or they are things that come with our body 3 You don t have to have previous exposure to an organism to have this type of immunity a Function of the immune 4 Quick response 5 Does not know specificity II Overview of natural immunity or the rapid response immune system Fig 14 1 A First line defenses WALL 1 Defense System Fig 14 1 a Epithelium Fig 14 2 14 3 Ch 22 1 1 2 forms 2 Stratified squamous epithelium Basal cells are stem cells that constantly divide Overlapping epithelial cells that become keratinized as they move towards the surface to waterproof the surface of our body Have a thick layer On the outside of the body Cuboidal epithelium stem cell at the bottom 1 Continually Grow and divide nucleus is lost and cell is no longer alive 2 Initiates keratin water proofing molecule 3 Just have dead skin on surface viruses cannot replicate in dead cell Tight junctions hold cells together 1 Keeps normal microbiota from coming in rd 3 degree burn have burned of cuboidal and now into the epidermis In epidermis have basal cuboidal cells Thick wall that does not allow anything in b Mucous membranes only one layer thick 1 Ciliated stratified pseudostratified columnar epithelium Most important ciliated epithelium what helps absorb nutrients in your guts One layer thick 1 Nucleus is fat 2 Mucous made by goblet cells in ciliated columnar epithelium Want mucus to be thick and sticky so that when you breath in a virus it ll get trapped into sticky mucous and pushed into the acid in the gut 3 mucociliary escalator cilia moves the mucous along ways to get rid of things trapped in mucous 1 Ingestion cilia sweep it to the stomach where the acids there destroy it a Swallowing 2 Expulsion sneezing when we breathe something in that the body wants to let out immediately 3 4 Problems Some bacteria actually like mucous membranes 1 Ex syphilis 2 Keeps them from drying out keeps it moist to survive Winter environment 1 Dry stale winter air reduces viciousness of mucous 2 Diseases due to breaks in the skin a Break in barrier of epithelium infection allow microbes in b Chronic obstructive pulmonary disease COPD chronic and it obstructs pulmonary function 1 Afflicts 10 20 of population and 4th leading cause of death in US 2 Smoking major risk factor for development of disease Physically destroys and kills epithelial cells causes loss of ciliated epithelium Breathing in cancer carcinogenic toxins 3 Bacterial infections play a significant role 4


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