Introduction of Immunity (Lab 1) - جامعة تكريت

‫جامعة تكريت‬ ‫كلية الطب‬ ‫فرع االحياء المجهرية الطبية‬ ‫م‪.‬م‪.‬جعفر جميل ابراهيم‬ ‫المرحلة الثانية‬ ‫‪Introduction of immunity‬‬ ‫‪Lab -1-‬‬ Learning Objectives 1-Define immunity and its types and...

‫جامعة تكريت‬ ‫كلية الطب‬ ‫فرع االحياء المجهرية الطبية‬ ‫م‪.‬م‪.‬جعفر جميل ابراهيم‬ ‫المرحلة الثانية‬ ‫‪Introduction of immunity‬‬ ‫‪Lab -1-‬‬ Learning Objectives 1-Define immunity and its types and innate immunity. 2-Classify types of immunity according to their function especially innate Immunity. 3-List the components of immune system. 4-Discuss the functions of immune system.  Definition of terms Immunology *The study of immune system or immunity *The study of all aspects of host defense against infection and of adverse consequences of immune responses. *The study of the physiological mechanisms. which enable the body to recognize materials as foreign and to neutralize, metabolize or eliminate them without injury to the host tissue. Definition of terms Immunology Immunity : State of protection from infectious diseases or Defined as resistance to disease specifically infectious disease. Immune system: the collection of cells, tissues and molecules that mediate resistance to infections. How do these specific protective mechanisms originate? The process by which these host defenses originate can be summarized by three actions: (1) the recognition of the foreign organism by specific immune cells, (2) the activation of these immune cells to produce a specific response (e.g., antibodies), (3) the response that specifically targets the organism for destruction. Innate immunity Innate immunity (also called natural, or native, immunity) refers to intrinsic mechanisms that are poised to react immediately, and thus constitute the first line of defense. Mediated by cells and molecules that recognize products of microbes and dead cells and induce rapid protective host reactions. Innate immunity: Properties Non-specific i.e., same response to the range of pathogens. Always present, ready to provide immediate defense. Has no memory i.e., same response after repeated exposure. Innate immunity: Functions 1. Initial most response to microbes 2. Eliminate damaged cells and initiate the process of tissue repair 3. Stimulates adaptive immune response Innate immunity: Components ✓ Physical (Epithelial barrier) ✓Cellular mechanisms {phagocytic cells (mainly neutrophils and macrophages), dendritic cells, natural killer cells etc.) ✓Humoral mechanisms (antibodies, complement proteins, antimicrobial peptides etc). Lines of defenses in immune system Innate defense system has two lines of defense: First - external body membranes (skin and mucosae) Second - antimicrobial proteins, phagocytes, and other cells Lines of defenses in immune system Adaptive defense system: Third line of defense attacks particular foreign substances. Takes longer to react than innate system. Innate Defense: Physical barriers Prevent entrance: 1- Structural barriers - effective with most microorganisms *Skin - epidermis = layers of tightly packed epithelial cells. Outer layer is dead cells and keratin, waterproofing protein *Inner layer skin dermis blood vessels, hair follicles, sweat glands, and sebaceous glands that produce an oily secretion called sebum *Cilia and cough reflex helps expel microbe containing mucous *Sneeze. Innate Defense: Physical barriers 2- Mucus membranes - conjunctivae, alimentary, respiratory, and urogenital tracts. Saliva, tears, and mucous secretions wash away invaders and contain antibacterial or antiviral substances. Innate Defense: Physical barriers Acidity (pH 5.6) of sweat, sebaceous glands, vagina (pH 5) and stomach (pH 1) unfriendly to many microorganisms. Enzymes present in the skin and stomach, tears. Innate Defense: Physical barriers 3- Normal flora - out compete pathogens for attachment sites on the epithelial cell surface and for necessary nutrients. Natural & artificial immunity