2Viruses Viruses are non-living. Only characteristic of living organisms is ability to reproduce.Obligate intracellular parasites.
3Viruses Viruses are composed of; a nucleic acid- can be dna OR rna. Protein coat called a capsid which can be different shapes; helical, polyhedralSome viruses have an envelope of lipids that surround the capsid when they leave a host cell
5Viruses Retroviruses RNA core. Must contain an enzyme called reverse transcriptase.RNA + reverse transcriptase--DNA—inserts into host cell’s DNA—host cells ribsomes make mRNA—Proteins are part of new viruses
6Viroids & Prions Viroids: Prions: Naked RNA that can replicate. Infectious proteins.Disrupt the cells activities.
12Nonspecific Defenses Pathogens are disease causing agents. Resistance is your bodies ability to defend against pathogens.Your immune system gives you resistance.
13Identifying Pathogens Koch’s PostulatesPathogen must occur in body of organism with the disease.Pathogen should be isolated and grown in culture.Inoculated animal should develop the disease.Same pathogen should be grown in culture.
14Physical Barriers to Disease Nonspecific defense.Sweat, oils, & waxes.Mucous membranes.HCL of stomach.
15Fever Pathogens that attack human body like 98.6 f. best. Hypothalamus raising temperature of body increases effectiveness of WBC’s.Decreases effectiveness of pathogen.
16Proteins Interferons Complement Proteins Chemical released by cells infected by viruses.Causes surrounding cells to resist infection.Complement ProteinsCirculate in your blood and become active when they encounter certain pathogens
17Inflammatory Response Inflammatory response occurs when pathogen penetrates the skin.Nonspecific- any pathogen causes an inflammatory response if your skin is broken
19Inflammatory Response What occurs:Damaged cells release histamines.Causes increase in permeability.Causes vasodialation (swelling)Allows phagocytes to digest and destroy foreign matter.Phagocytes are drawn towards histamine
20Non specific Cellular Defense NeutrophilsMost common phagocyteKill pathogens using phagocytosis.Circulate in blood stream.Migrate towards site of infection. (chemotaxis)Move out of the blood stream (emmigration)
21Non specific Cellular Defense Macrophages- another type of phagocyteStationed in certain tissues.Destroy by phagocytosis.Rid the body of debris and damaged cells.
22Non specific Cellular Defense Natural Killer CellsCytotoxic T CellsAttack cells which have been infected by pathogen.Kills cancer cells.Kills by puncturing cell membrane.
24How WBCs Recognize Pathogens All of your cells are marked as “self” by proteins in your cell membrane.Nonspecific WBCs recognize your proteins.They leave these cells alone.Any cell that does not have “self” markers are attacked.
25Summary of Immune System To Date: Body has different “lines of defense”.BarriersSkin, mucous membranes, secretions.Non specific defenses.Macrophages, neutrophils, natural killer cells.Interferon, compliment proteins.Specific defenses.
26RBC of different blood type has antigens Specific DefensesIf pathogens enter the body, the immune system responds.Response is to specific pathogens. (Single type)RBC of different blood type has antigens
27Immune System Organs Thymus gland Spleen Bone marrow Lymph nodes LymphocytesB cellsT cells (helper, cytotoxic)
28Immune Response how antigens are 1st recognized by lymphocytes- cell mediated response Pathogen has proteins (antigens) on its surface.Macrophages destroy pathogen.Macrophages present parts of the pathogen (antigen) to helper T cells.Macrophages release interleukinsInterleukins causeCytotoxic Killer T cells to destroy infected cellCreation of B cells
29How Antigens are Recognized Lymphocytes then remember the antigen.Attack and destroy if in body.Cell mediated immune response.Antibody and cell mediated immune response are happening at the same time in the body.
30Cell Mediated Immune System Macrophages present portion of pathogen to B Lymphocyte cells.B cells learn pathogen structure and divide into plasma cells and memory cellsAntibodies are madeBacteria adhering to T lymphocyte.
32Antibody Mediated Immune System Plasma cells produce proteins called antibodies.Antibodies recognize and attach to pathogen.Antibodies are Y-shaped proteins.
33Antibody Mediated Immune System The two arms of the antibody are identical.Antibodies match proteins of pathogen.Actions of antibodies.
34Antibody Mediated Immune System Primary response occurs the first time exposure to pathogen occurs.Secondary response occurs when pathogen invades again.Faster reaction.Stronger reaction.Memory B cells.
35Immunity & Vaccination Naturally acquired active immunity.Your are exposed to pathogen in everyday life.Naturally acquired passive immunity.Breast milk.Mom’s antibodies prior to to birth.Artificially acquired active immunity.Vaccination.Artificially acquired passive immunity.You are given a shot of antibodies.