NU 551 UNIT 2 EXAM QUESTIONS ANSWERED CORRECTLY LATEST UPDATE 2026

NU 551 UNIT 2 EXAM QUESTIONS ANSWERED CORRECTLY LATEST UPDATE 2026 Innate Immunity - Answers Natural barriers and inflammation Present at birth Initial response to injury Adaptive/ Acquired Immunity - Answers Immunity which develops over a life time Long term protection against specific invaders Involves memory Examples Of Innate Immunity - Answers Skin Epithelial cells in upper respiratory tract GI tract through vomit & defecation 1st 2nd and 3rd Line of Defense - Answers Physical and biochemical barriers and the human micro biome Inflammatory response Adaptive Immunity Normal Flora is Now Known As - Answers normal microbiome Normal Microbiome - Answers colonized combination of bacteria and fungi unique to anatomical location and individual Commensal - Answers benefiting the microorganism Mutualistic - Answers benefiting both the microorganism and the body Functions of the Microbiome - Answers -produce enzymes -synthesize metabolites -release antibacterial substances -competes w/pathogens for nutrients, block attachments to epithelium, first step infectious process -induces gut-associated typhoid tissue -contributes to communication btw brain and GI tract Opportunistic Pathogens - Answers harmless under normal conditions -can cause disease when defense mechanisms lower Lysozyme - Answers enzyme which attacks the cell walls of gram-positive bacteria Where are lysozymes found - Answers -perspiration -tears -saliva Antimicrobial peptides - Answers Short peptides which kill and inhibit growth of bacteria, fungi & viruses Defensins - Answers Antimicrobial peptides produced by neutrophils and epithelial cells that defend against bacterial infection by disrupting bacterial membranes Collectins - Answers Soluble glycoproteins that facilitate the ability of macrophages to recognize and kill pathogenic microorganisms and can activate the lectin pathway of the complement system. Inflammation - Answers protective response to injury and disease (cellular or tissue damage) Function of Inflammation - Answers -destroy pathogens -trigger adaptive immune response -limit the extent of tissue damage -initiat the healing process Inflammatory Response is Characterized By - Answers 1. occurs in vascular tissue 2. activation is rapid 3. is both cellular and chemical in nature 4. is non-specific Vascular Inflammatory Response Process - Answers -coagulation: clotting cascade -vasodilation -increased vascular permeability -WBC adhesion Phagocytes - Answers neutrophils and macrophages A type of white blood cell that ingests invading microbes Macrophage - Answers Free macrophages vs fixed macrophages Act as the 1st phagocyte that invading organisms encounter upon entering the host Has surface receptors to engulf and destroy bacteria What do macrophages do? - Answers Process and present antigens in the initiation of the immune response Secrete substances that initiate and coordinate the inflammatory response or activate lymphocytes Can also remove antigen-antibody complexes & destroy malignant host or virus-infected cells Purpose of Inflammation - Answers -to localize infection/prevent spread of pathogens -to destroy and detoxify pathogens -to prepare for healing and repair -facilitate development of adaptive immunity Non-specific response - Answers respones/process is the same regardless of type of injury/stimulus Macroscopic Hallmarks of Inflammation - Answers redness, heat, swelling, pain, and sometimes impairment of function Microscopic Hallmarks of Inflammation - Answers Vasodilation Increased capillary permeability Accumulation of fluid and cells at inflammatory site Mast Cells - Answers the most important mediator cell of inflammation initiate inflammation by releasing biochemical mediators Chemical release by degranulation and synthesis Link the innate and adaptive systems Degranulation - Answers Release of contents of mast cell granules Synthesis - Answers Production and release of mediators in response to stimulus Types of molecular patterns recognized by patter recognition receptors (PRRs) - Answers -pathogen associated molecular:molecules expressed by infectious agents -damage associated molecular: products of cellular damage Cytokine - Answers Biochemical mediator Responsible for activating other cells and regulating the inflammatory response Include chemokines, interleukins, interferons, and other molecules Monokines - Answers cytokines secreted by monocyte Lymphocytes - Answers Activate macrophages Initiate immune response Natrual Killer Cells (NK Cells) - Answers Type of lymphocyte Eliminate cells infected with viruses and cancer Inhibitory and activating receptors to allow differentiation between normal and abnormal cells Produce cytokines and toxic molecules Lymphokines - Answers cytokines secreted from lymphocytes Chemokine - Answers cytokine which attract leukocytes to sites of inflammation -synthesized by many cell types including macrophages, fibroblasts, and endothelial cells Endothelial Cells - Answers Regulate circulation through micro-vessels Control movement of water and solutes Maintain normal blood flow What happens when endothelial lining is damaged? - Answers Initiates platelet activation Promotes recruitment of leukocytes Facilitates wound healing Protective Functions of Inflammation - Answers Prevention of infection and further damage cause by invading microorganisms Limitation of the scope of inflammatory process Preparation of injury for healing and repair Facilitation of the development of adaptive immunity 3 Plasma Protein Systems - Answers Complement System Clotting System Kinin System Complement System - Answers Intensifies the capacity of antibodies and phagocytes to clear pathogens and damaged cells and activate inflammation Membrane Attack Complex - Answers Part of complement system Leads to bacterial destruction and tissue injury by creating pores in outer membranes of cells or bacteria Pores facilitate infection of water into cells culminating in cellular death 3 Pathways of Complement System - Answers Classical Alternative Lectin Classical Pathway - Answers activated by antibodies bound to antigen, which interact with complement system Alternative Pathway - Answers activated by substances found on the surface of infectious microorganisms Lectin Pathway - Answers Independent of antibodies and is activated by plasma proteins - MBL The Clotting System - Answers stops bleeding, localizes microorganisms, and provides a meshwork for repair and healing. Blood Clot - Answers meshwork of fibrin strands and platelets Kinin System - Answers system activated by Hageman factor as part of the inflammatory response; includes bradykinin Blood Cells are Divided Into - Answers Erythrocytes Platelets Leukocytes (WBC) Bradykinin - Answers most important product of the kinin system and causes vascular permeability, smooth muscle contraction, and pain Pattern Recognition Receptors - Answers (PRR) able to recognize category of invaders (bateria, virus, fungus, parasite) in order to initiate appropriate cytokine response. These receptors are presented on macrophages and dendritic cells. Interleukins - Answers produced by macrophages and lymphocytes in response to stimulation of PRR or by other cytokines Serve to alter the behavior of cells Proinflammatory Cytokines - Answers TNF-a IL1 IL6 TNF-alpha - Answers Secreted by macrophages *Mediates septic shock.* induces fever causes muscle wasting and intravascular thrombosis IL-1 - Answers Enhances innate and adaptive immunity Acts as growth factor Anti-inflammatory Cytokines - Answers IL-10 and TGF-beta IL-10 - Answers Suppresses activation and proliferation of lymphocytes Limits production of proinflammatory cytokines TGF-beta - Answers Transforming Growth Factor Suppress activity of lymphocytes Downregulate production of proinflammatory cytokines Interferons (IFNs) - Answers Antiviral proteins secreted by T cells IL-6 - Answers Induces liver cells to produce inflammatory proteins IFNs Type 1 - Answers Produced and released by virally infected host cells Induce antiviral proteins and protect neighboring healthy cells Histamine - Answers Chemical stored in mast cells that triggers dilation and increased permeability of capillaries. Binding of histamine to the H1 receptor is proinflammatory IFNs Type 2 - Answers Produced by lymphocytes Activate macrophages and increases capacity to detect and process abnormal cells Antihistamines - Answers Drugs that block binding of histamine to its receptors resulting in decreased vascular effects H1 Receptor - Answers present in smooth muscle cells of the bronchi -induces bronchoconstriction Cells of the Innate Immune System - Answers Neutrophils Basophils Eosinophils Mast Cells Dendritic Cells Monocytes Macrophages Natural Killer Cells H2 Receptor - Answers Anti-inflammatory, present in parietal cells of the stomach mucosa and induces secretion of gastric acid H2 Blockers - Answers block H2 receptors in the stomach to prevent the release of acid to treat heartburn, peptic ulcers, and GERD Leukotrines - Answers Lipids that induce smooth muscle contraction and increased vascular permeability