Introduction and Overview of immune system

Introduction and Overview of immune system - ‫بسم...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: ‫بسم اللة الرحمن‬ ‫الرحيم‬ Introduction Introduction The immune system is: Defense body mechanism an interacting set of specialized cells and proteins designed to identify and destroy foreign invader Introduction Introduction The immune system must be able to: differentiate between material that is a normal component of the body (“self”) and material that is not native to the body “nonself” A highly specialized receptors present for discriminating between ”self” and “nonself” body components Introduction Introduction *The discrimination between “self” and “non­self” and the subsequent destruction and removal of foreign material is accomplished by the two arms of the immune system 1) The innate (natural or nonspecific) immune system 2) The adaptive (acquired or specific) immune system *These two systems perform many of their functions by cooperative interactions Immunity Immunity Innate immunity Adaptive immunity Humeral Cell­mediated Components Components Macrophages antigen presenting cells Granulocytes T­cells Natural killer cells B­cells Complement Antibodies Other chemicals: HCL, lysozyme Complement Characteristics Characteristics * Action is immediate * Action requires days to develop * Response is non­specific * Response is specific * Response is not enhanced on * Response is enhanced on repeated exposure to pathogen repeated exposure to pathogen Overview of the innate immune system Overview * It is the first line of defense * It is active at the time of infection • It consists of: a­ protective cellular (WBCs and derivatives) b­ chemical components The response of the innate immune system The It is divided into two stages: 1­ non­inflammatory reaction (body’s static defenses) skin, gastric pH, lysozyme in tears, saliva, mucous 2­ local inflammation promotes migration of phagocytes and plasma protein into infected tissues The phagocytes respond to surface structures present in large groups of microorganisms (peptidogcan, mannose) Role of external body surfaces Role * The skin consists of sheets of dry, cornified epithelial cells Intact skin act as barrier to bacteria and viruses * Hair follicles and sebaceous glands produce: Antibacterial substances (fatty acids and enzymes) * Normal microbial flora compete with: potential pathogens Role of internal body surfaces Role The normal movement of fluids and mucous act as mechanical factors for cleaning internal surfaces of: Respiratory tract Gastrointestinal tract Genitourinary tract Acute Inflammation Resulting From Infection Acute Inflammation is a nonspecific response of living tissue to localize and eliminate the injurious agent The injury may be: physical, chemical or biological The Inflammatory Response The Specialized cells and serum proteins move from plasma to interstitial spaces to provide an immediate defense The Inflammatory Response The The inflammatory cells include: ­ Phagocytes which destroy the invading organisms by phagcytosis followed by intracellular digestion ­ Natural killer cells which limit infection by releasing compounds toxic to organisms The Inflammatory Response The * Serum components: Acute phase proteins (e.g. C­reactive protein) ­ C­reactive protein is produced by liver in response to tissue damage ­ C­reactive protein binds to the cell walls of bacteria and activates the complement system resulting in the opsonization and lyses of pathogenic organisms Role of Phagocytosis Role 1­ Chemotaxis & attachment a­ Attraction by chemotact. Subst. ( microbes,inflam. tissues) b­ Attachment by receptors on surfaces of phagocytes 2­ Ingestion * Phag. pseudopodia surround organism forming phagosom * Opsinins and co factors enhance phagocytosis * Fusion with phag. granules and release digestive ,toxic contents 3­ Killing (two microbicidal routes) a­ Oxygen depended system (powerful microbicidal agents) Oxygen converted to superoxide, anion, hydrogen peroxide, activated oxygen and hydroxyl radicals. b­ Oxygen­independent system (anaerobic conditions) Digestion and killing by lysozyme. Lactoferrin, low pH, cationic proteins and hydrolytic and proteolytic enzymes Thanks Thanks ...
View Full Document

This note was uploaded on 12/21/2011 for the course STEP 1 taught by Professor Dr.aslam during the Fall '11 term at Montgomery College.

Ask a homework question - tutors are online