Disease and the Immune System Contemporary Issue – Immune System, Viruses and Bacteria Lecture Goals To understand the basic functions of the immune system. To identify the various cell types of the immune system and how they function to fight infections. To understand how long-term immunity is provided by the immune system. To understand how and why a virus infects human body cells. To understand the basic life cycle of a virus. To understand the nature of the common cold, shingles, and SARS. To understand how and why a bacteria attacks the body. To identify the various types of bacteria based on shape. To understand how bacteria reproduce. To understand the history of penicillin. To understand how antibiotics treat bacterial infections. To understand how E. coli and Anthrax affect humans. To understand how blood banks have historically been a source of infection for humans. Key Terms macrophage helper T-cell B-cell killer T-cell memory cell microbe cytokines antibodies virus ribosome attachment penetration biosynthesis maturation release shingles mutate severe acute respiratory syndrome (SARS) bacterium bacilli cocci spirillium binary fission penicillin Alexander Fleming Staphylococcus Escherichia coli shiga toxin unpasteurized anthrax spore cutaneous vaccine hepatitis (type A, B, C, D and E) immunoglobulin antibody interferon cirrhosis anemia transfusion

Overview of Lesson Immune system Viral infections Bacterial infections E. coli outbreaks Advance Organizer The first portion of the lecture will describe the various cells of the immune system and explain how they function to fight infection and provide immunity. The second portion of the lecture will describe viruses. Emphasis will be given to how and why a virus infects a human body cell, the life cycle of a typical virus, and how the immune system combats a viral infection. Chickenpox virus, common cold viruses, and SARS will be discussed. The third portion of the lecture will describe bacteria. Emphasis will be given to how and why a bacterium infects a human body, how a bacterium replicates, and how antibiotics work to fight bacterial infections. The history of penicillin will be discussed, as will two different bacterial infections; E. coli and anthrax. The last portion of the lecture will describe how blood banks were once a common source of infectious agents to humans and how testing and screening has helped to eliminate this problem.

Streptococcus Pneumoniae Bacteria Ear infections Meningitis Pneumonia Influenza Virus Flu Illnesses caused by bacteria, viruses, fungi and parasites are called infectious diseases. Communicable diseases are illnesses that can be spread from one person to another. We commonly refer to communicable diseases as contagious. Many illnesses are contagious before symptoms appear. A disease is any change, other than an injury, that disrupts the normal functioning of the body. It is the inability to maintain homeostasis.

Causes Inheritance: sickle-cell anemia, hemophilia Toxic Substances: cigarette smoke, alcohol Poor Nutrition: ricketts, anorexia, scurvy Organ Malfunction: heart disease, diabetes Personal Behavior: drug addiction, alcoholism

Causes continued Pathogens: organisms that enter the body and cause infectious diseases Antigens Toxins that pathogens produce that cause harm to an organism. Are pathogens abiotic or biotic? Examples of pathogens are viruses, bacteria, fungi, and parasites.

Pathogens Examples of diseases caused by viruses: mono, flu, common cold, chicken pox, small pox, pertussis, AIDS chicken pox small pox AIDS

Pathogens Pathogens continued: Bacteria: Tuberculosis, E. coli, cholera, tetanus E. coli cholera tuberculosis tetanus

Pathogens c) Fungi: ringworm, athlete’s foot, jock itch ringworm

Pathogens d) Parasites: lice, malaria, dysentery, tapeworm, malaria in red blood cells tapeworm Amoebic dysentery lice

Immunity Immunity Immune System ability of the body to fight infection and/or foreign invaders by producing antibodies or killing infected cells. Immune System body system that maintains homeostasis by distinguishing harmful from nonharmful Organisms that enter the body and responding

Parts of the Immune System Blood - White Blood Cells in particular. Lymph nodes Thymus Gland – Produces T Lymphocytes Bone Marrow – Produces B Lymphocytes

Lymphatic system   A network of glands and vessels that drain interstitial fluid from body tissues and return it to the circulatory system. Fluid is “scanned” for foreign cells

Lymph Organs bone marrow lymph nodes spleen thymus

Function of 2 Main Groups of Cells 1. Leukocytes—Non-specific defense. Rely on Phagocytosis to ingest invading microbes. They include Macrophages and White Blood Cells. 2. Lymphocytes—Provide high specificity and diversity to the immune system. Allow for extremely aggressive response microbial attack. They include B-Cells and T-Cells

How does the body fight infection/foreign invaders? The Body’s THREE lines of Defense First Line of Defense – The Skin Provides Physical and Chemical barriers Physical – hard to penetrate, made of indigestible keratin Chemical – tears, sweat

Second Line of Defense – Nonspecific Immune Response These are defenses the body uses no matter what the invader may be. These defenses include: Phagocytosis – done by Macrophages Natural Cell Killers Inflammation - caused by release of Histamine from leukocytes Fever – caused by histamines. The fever (high temp) kills invaders by denaturing their proteins. Macrophage: A phagocytic cell found in the liver, spleen, brain and lungs. Travels to all areas of the body to find and eat pathogens.

Third Line of Defense – Specific Immune Response This is a specific response to a specific pathogen/antigen. The response involves the creation of Antibodies.

Antibodies Y-shaped protein molecule. Made up of variable and constant regions. Made up of Heavy and Light chains. Produced by B-Lymphocytes Function: Recognize antigens, bind to and deactivate them. Note: Variable region recognizes the antigens.

How An Antibody Operates/Works? Deactivation of a bacterium by an antibody.