Chapter 23 Immune System Section 1: Infectious Diseases Section 2: The Immune System Section 3: Noninfectious Disorders

Pathogens Cause Infectious Disease Chapter 23 Immune System 23.1 Infectious Diseases Pathogens Cause Infectious Disease An infectious disease is a disease that is caused when a pathogen is passed from one organism to another. Pathogens are the cause of infectious disease. Bacteria Fungi Viruses Parasites Protozoans

Chapter 23 Immune System 23.1 Infectious Diseases Koch’s Postulates

A disease reservoir is a source of the pathogen in the environment. Chapter 23 Immune System 23.1 Infectious Diseases Spread of Disease A disease reservoir is a source of the pathogen in the environment. Reservoirs might be animals, people, or inanimate objects, such as soil.

Humans are the main reservoir for pathogens that affect humans. Chapter 23 Immune System 23.1 Infectious Diseases Human Reservoirs Humans are the main reservoir for pathogens that affect humans. An individual that is symptom-free but capable of passing the pathogen is called a carrier.

Chapter 23 Immune System 23.1 Infectious Diseases Animal Reservoirs Other animals also are reservoirs of pathogens that can be passed to humans. Influenza Rabies

Contaminated water or food Chapter 23 Immune System 23.1 Infectious Diseases Other Reservoirs Soil Contaminated water or food

Transmission of Pathogens Chapter 23 Immune System 23.1 Infectious Diseases Transmission of Pathogens Direct contact Indirect contact through air Vectors Indirect contact by objects

The virus damages tissues and even kills some cells. Chapter 23 Immune System 23.1 Infectious Diseases Symptoms of Disease The virus multiplies in the cells and leaves the cells either by exocytosis or by causing the cell to burst. The virus damages tissues and even kills some cells. Harmful chemicals or toxins might be produced.

As outbreaks of diseases spread, certain patterns are observed. Chapter 23 Immune System 23.1 Infectious Diseases Disease Patterns As outbreaks of diseases spread, certain patterns are observed. The Centers for Disease Control and Prevention (CDC), and the World Health Organization (WHO) monitor disease patterns to help control the spread of diseases.

Treating and Fighting Diseases Chapter 23 Immune System 23.1 Infectious Diseases Treating and Fighting Diseases An antibiotic is a substance that can kill or inhibit the growth of other bacteria. Penicillium Erythromycin

Helps to prevent disease Chapter 23 Immune System 23.2 The Immune System Nonspecific Immunity The body has a number of defenses in the immune system that fight off pathogens. These defenses are nonspecific because they are not aimed at a specific pathogen. Helps to prevent disease Helps to slow the progression of the disease

Dead skin cells help protect against invasion by microorganisms. Chapter 23 Immune System 23.2 The Immune System Skin Barrier Dead skin cells help protect against invasion by microorganisms. Bacteria that live symbiotically on the skin digest skin oils to produce acids that inhibit many pathogens.

Saliva, tears, and nasal secretions contain the enzyme lysozyme. Chapter 23 Immune System 23.2 The Immune System Chemical Barriers Saliva, tears, and nasal secretions contain the enzyme lysozyme. Lysozyme breaks down bacterial cell walls, which kills pathogens. Mucus acts as a protective barrier, blocking bacteria from sticking to the inner epithelial cells.

Nonspecific Responses to Invasion Chapter 23 Immune System 23.2 The Immune System Nonspecific Responses to Invasion The body has nonspecific immune responses to pathogens that get beyond its barriers. Cellular defense Interferon Inflammatory response

Chapter 23 Immune System 23.2 The Immune System Cellular Defense Phagocytosis is the process by which phagocytic cells surround and internalize the foreign microorganisms. The phagocytes release digestive enzymes and other harmful chemicals from their lysosomes, destroying the microorganism.

Virus-infected cells secrete a protein called interferon. Chapter 23 Immune System 23.2 The Immune System Interferon Virus-infected cells secrete a protein called interferon. Interferon binds to neighboring cells and stimulates these cells to produce antiviral proteins which can prevent viral replication in these cells.

Inflammatory Response Chapter 23 Immune System 23.2 The Immune System Inflammatory Response Increased blood flow to the infected area makes blood vessels more permeable to allow white blood cells to escape into the infected area.

Specific Immunity Lymphatic system Chapter 23 Immune System 23.2 The Immune System Specific Immunity Lymphatic system Organs and cells that filter lymph and blood and destroy foreign microorganisms

Lymphatic Organs Lymphatic tissue Lymphocytes Chapter 23 Immune System 23.2 The Immune System Lymphatic Organs Lymphatic tissue Lymphocytes Lymphocytes are a type of white blood cell that is produced in red bone marrow.

These lymphatic organs include Chapter 23 Immune System 23.2 The Immune System These lymphatic organs include Lymph nodes Tonsils Spleen Thymus gland Diffused lymphatic tissue found in mucous membranes of the intestinal, respiratory, urinary, and genital tracts

3rd line: Lymphocytes Specific defense responds to specific invaders B cell Specific defense responds to specific invaders recognizes specific foreign antigens white blood cells B cells & antibodies T cells

B cells & Antibodies B cells Plasma B cells B. Memory B cells white blood cells that attack roaming invaders mature in bone marrow Plasma B cells make antibodies against invader immediately B. Memory B cells remembers invader can make antibodies quickly the next time protects you from getting disease more than once

Antibodies Antibody a protein molecule which attaches to the ANTIGEN on a pathogen and then either: The antibody causes the pathogen to be unable to enter any more body cells 2. The antibody attracts a WBC to engulf the pathogen

B cells immune response Y Y B cells release antibodies patrol blood forever invader (foreign antigen) Y Y Y Y “reserves” memory B cells Y B cells Y Y recognition Y Y 10 to 17 days

You need trained assassins to kill off these infected cells! What if the attacker gets past the B cells in the blood & actually infects some of your cells? You need trained assassins to kill off these infected cells! Attack of the Killer T cells! 2006-2007

T cells T cells mature in thymus Helper T cells B. Killer T cells sounds the alarm for rest of immune system B. Killer T cells destroys infected body cells C. Memory T cells remembers invader & reacts against it again quickly

Thymus

Immune response invader skin skin invaders in body invaders in blood invaders infect cells macrophages B cells helper T cells T cells plasma B cells memory B cells memory T cells killer T cells Y antibodies

Exposure to harmless version of germ (pathogen) Vaccinations Exposure to harmless version of germ (pathogen) stimulates immune system to produce antibodies to invader rapid response if future exposure Most successful against viral diseases

Jonas Salk 1914 – 1995 Developed first vaccine against polio Poliomyelitis (polio) is caused by a virus that enters the body through the mouth. The virus multiplies in the intestine and invades the nervous system. It can cause total paralysis in a matter of hours. One in 200 infections leads to irreversible paralysis. Among those paralyzed, 5-10 percent die when their breathing muscles are immobilized. Polio mainly affects children under age 5. April 12, 1955

Polio epidemics 1994: Americas polio free 1916 The first major polio epidemic strikes in the United States; 27,000 people suffer paralysis and 6,000 die. Increasing numbers of outbreaks occur each year. 1921 Franklin D. Roosevelt is diagnosed with polio. 1928 Iron lungs are introduced to help patients with acute polio breathe. 1932 Franklin D. Roosevelt is elected President of the United States 1949 Dr. John Enders, Dr. Frederick Robbins and Dr. Thomas Weller develop a way to grow poliovirus in tissue culture, a breakthrough that aided in the creation of the polio vaccine. Their work earned the three scientists the Nobel Prize in physiology and medicine in 1954. 1952 The United States reports 57,628 polio cases -- the worst U.S. epidemic on record. 1979 The last U.S. case of polio caused by wild poliovirus is reported. 1988 Worldwide, polio continues to affect some 350,000 people in 125 countries. 1994 The Americas are certified polio-free. 2000 The Western Pacific region is certified polio-free. 2002 Europe is certified polio-free.

Protecting you from disease Vaccinations (Active Immunity) Advantage don’t get illness long term immunity produce antibodies for life works against many viruses & bacteria Disadvantage not possible against all invaders Breastfeeding (Passive Immunity) mother’s milk gives baby antibodies & keeps baby healthy IMPORTANT PROTECTION antibodies pass from mother to baby in breast milk

Protecting you from disease Antibiotics = medicine advantage kill bacteria that have successfully invaded you make you well after being sick disadvantage use only after sick only good against bacteria possible development of resistance by bacteria (if don’t use correctly) can get sick again

Organ Transplants When a person receives someone else's organ, the organ has foreign antigens on it. The recipient’s white blood cells will recognize the organ as foreign, and attack it. So, the recipient has to take immunosuppressant drugs

Immune system malfunctions Auto-immune diseases immune system attacks own cells lupus antibodies attack many different body cells rheumatoid arthritis antibodies causing damage to cartilage & bone diabetes beta-islet cells of pancreas attacked & destroyed multiple sclerosis T cells attack myelin sheath of brain & spinal cord nerves

Immune system malfunctions Allergies over-reaction to harmless compounds allergens proteins on pollen proteins from dust mites proteins in animal saliva body mistakenly thinks they are attackers

Diseases of the immune system HIV: Human Immunodeficiency Virus infects helper T cells helper T cells can’t activate rest of immune system body doesn’t hear the alarm AIDS: Acquired ImmunoDeficiency Syndrome infections by opportunistic diseases death usually from other invading diseases or cancer

HIV-AIDS HIV is transmitted by bodily fluid contact HIV causes AIDS Sexual contact Blood-to-blood contact Using unclean needles HIV causes AIDS AIDS- Acquired Immune Deficiency Syndrome