IMMUNE SYSTEM SC.912.L SC.912.L Explain the basic functions of the human immune system, including specific and nonspecific immune response, vaccines, and antibiotics

KNOWLEDGE AND SKILLS Identify and/or explain the basic functions of the human immune system, including specific and nonspecific immune responses Describe how the human immune system responds to vaccines and/or antibiotics Explain the significance of genetic factors, environmental factors, and pathogenic agents to health from the perspective of both individual and public health

PATHOGENS AND HUMAN ILLNESS Germ theory states that microscopic particles cause certain diseases proposed by Louis Pasteur Joseph Lister – 1 st doc to clean surgical tools Robert Koch - postulates support the theory Disease-causing agents are called pathogens

DIFFERENT TYPES OF PATHOGENS Bacteria cause illness by destroying cells release toxic chemicals Viruses force host cells to make more viruses Fungi take nutrients from host cells occur in warm and damp places Protozoa use host cells to complete their life cycles take nutrients from host cell Parasites are multicellular organisms grow and feed on a host possibly kill the host

HOW DO PATHOGENS INFECT? Direct contact Exchange of body fluids Hand shaking Indirect contact touching an infected surface breathing in infected air Vectors Mosquitoes Fleas

THE IMMUNE SYSTEMS CONSISTS OF ORGANS, CELLS, AND MOLECULES THAT FIGHT INFECTIONS

FIRST LINE OF DEFENSE Skin Provides a physical barrier Secretes oils and sweat Mucous membranes Lined with cilia Circulatory system Transports cells

CELLS AND PROTEINS FIGHT THE BODY’S INFECTIONS White blood cells (leukocytes) Phagocytes engulf and destroy pathogens T cells destroy infected cells B cells produce antibodies Proteins Complement proteins weaken pathogen membranes Antibodies make pathogens ineffective Interferons prevent viruses from reproducing

CYTOTOXIC T CELL IN ACTION

IMMUNITY Passive immunity – transferred through DNA or mother’s milk Active immunity – produced in response to specific pathogen

IMMUNE RESPONSE The immune system has many responses to pathogens and foreign cells

NONSPECIFIC RESPONSES The same for every pathogen Inflammation - swelling, redness, pain Fever – body temp increased Stimulates production of interferons

SPECIFIC RESPONSES Begin with the detection of antigens Antigens are surface proteins on pathogens Each pathogen has a different antigen.

TYPES OF SPECIFIC RESPONSES Cellular immunity - T cells to destroy infected body cells Humoral immunity uses B cells to produce antibodies Both responses produce memory cells. specialized T and B cells provide acquired (active) immunity

THE IMMUNE SYSTEM REJECTS FOREIGN TISSUES Tissue rejection occurs in organ or tissue transplants. Tissue rejection is the result of an immune response. immune system detects protein markers on the donor tissue makes antibodies against the donor’s tissue

IMMUNITY AND TECHNOLOGY

METHODS TO CONTROL PATHOGENS Antiseptics kill pathogens outside of the body do not target specific pathogens Vinegar, soap Antibiotics kill pathogens inside the body target one specific bacterium or fungus not effective against viruses (not living)

A VIRUS IS NOT ALIVE Read the comic Explain why viruses are not considered living things even though they have their own DNA

ANTIBIOTIC RESISTANCE

Overuse of antibiotics can cause them to become ineffective Some bacteria in a population have genes that make them immune to antibiotics These bacteria spread the gene, making the antibiotics useless

ANTIBIOTIC RESISTANCE Read the comic Explain how the bacterium population will rise again What processes will occur Be specific!

VACCINES Artificially produce acquired immunity Contain the antigen of a weakened pathogen Stimulates a specific immune response Causes memory cells to be produced Allows immune system to respond quickly to infection

OVERREACTION OF THE IMMUNE SYSTEM Allergies caused by allergens Allergens are antigens cause inflammation Autoimmune disorders Explain what is happening here

AUTOIMMUNE DISORDERS Read the comic Explain what is happening