CH. 24 The Immune System

Pathogens: Bacteria, Viruses, Parasites, Fungi The immune systems consists of organs, cells, and molecules that fight infections and protect us from invaders. Pathogens: Bacteria, Viruses, Parasites, Fungi Innate (nonspecific) immunity – present at birth; not specific for the invader 2. Acquired (specific) immunity – develops throughout life; specific for the invader

Innate Immunity External Barriers – 1st line of defense Skin, sweat – good pH, digestive enzymes Mucus membranes – good trap, digestive enzymes Tears – good trap, digestive enzymes Stomach acid – good pH, digestive enzymes

Antibiotics and antiseptics cause pathogens to burst.

The immune system has many responses to pathogens and foreign cells that pass the initial barriers.

Phagocytic cells – capture and digest (lysozyme) Innate Immunity Phagocytic cells – capture and digest (lysozyme) Macrophages – blood and tissue, long lives Neutrophils – most abundant in blood, short lives Eosinophils – specialty is parasite Dendritic cells – connection to the acquired immune response Natural Killer Cells Attack virus-infected, cancer cells Kill by poking holes in abnormal cells (cytotoxic)

White blood cells (Leukocytes/ Lymphocytes) attack infections inside the body. Phagocytes engulf and destroy pathogens. pseudopods E.coli

Phagocyte Reaches Out To Capture Bacteria Pseudopod E. Coli For internal use only, property of Coulter Corporation

Phagocyte Draws Bacteria in for Phagocytosis E. Coli Pseudopods For internal use only, property of Coulter Corporation

In fever, body temperature increases. Low fevers stimulate white blood cells to mature. High fevers can cause seizure, brain damage, and even death.

Innate Immunity- Nonspecific Responses to pathogens Inflammation – redness and heat Fever Antimicrobial – kill or stop reproduction complement – pokes holes in invading cells Interferons – anti-viral

Acquired (SPECIFIC) Immunity Acquired immunity allows specific recognition of any invader (has specific receptors) Acquired immunity provides memory to the immune response

T helper T cytotoxic antibodies Acquired Immunity: two specific immune responses. T cells destroy infected cells. B cells produce antibodies. T Cells B Cells T helper T cytotoxic antibodies

Acquired Immunity (SPECIFIC) Specific immune responses begin with the detection of antigens. Receptors are proteins which recognize a single type of molecule - the antigen, which is found on foreign material bacteria antigen

Acquired Immunity B cells antibodies Plasma Cells B Cell Activated divide

Acquired Immunity B cells MemoryB Cell B Cell

Acquired Immunity Activated T cell Attack things outside the cell antibodies Killed by HIV HelperT Cell HELP B cell Cytotoxic T Cell HELP Kill infected & cancer cells (when in or on your own cell)

Acquired Immunity- Memory cells The next time this memory cell sees this antigen: Primary response Secondary Primary exposure secondary exposure

Cytotoxic T Cells Attack A Tumor Cell part I Tumor Cell Cytotoxic T Cell For internal use only, property of Coulter Corporation

Cytotoxic T Cells Attack A Tumor Cell part II Tumor Cell Cytotoxic T Cell For internal use only, property of Coulter Corporation

Cytotoxic T Cells Attack A Tumor Cell part III Tumor Cell Skeleton Cytotoxic T Cell For internal use only, property of Coulter Corporation

Vaccines artificially produce acquired immunity. Vaccines also control pathogens and disease. given to prevent illness contain the antigen of a weakened pathogen

Vaccination provides immunity. stimulates a specific immune response Antigens in a vaccine trigger an immune response, and memory B cells are made. 1 memory B cells causes memory cells to be produced A memory B cell is stimulated when the real pathogen binds to it. 2 allows immune system to respond quickly to infection The B cell quickly activates and makes antibodies that fight the pathogens before you get sick. 3 has such a fast response, a person will not get sick Vaccination animation

HIV Virus Attacks a T Cell For internal use only, property of Coulter Corporation

Diseases and the Immune System Our immune system can tell the difference between foreign and self – when it can’t  autoimmune disease Diabetes Multiple sclerosis arthritis Sometimes we over react to things that are foreign but not harmful  allergy Asthma Food allergy Hives

Diseases and the Immune System Sometimes our immune system is depleted or destroyed Stress HIV/AIDS Sometimes we want something foreign to be tolerated but it gets destroyed by our immune system Blood transfusions Organ transplants

HIV and AIDS webquest- Due Friday, 3/9! Go to Holt textbook website: Ch. 31 http://www.classzone.com/cz/ot/bio_webquest/31/intro.jsp Research and answer questions on separate paper or print answers.

Immunity Acquired Innate Active Immunity Passive Immunity Acquired resistance to infection Inborn resistance to infection Active Immunity Passive Immunity Produced by antibodies that develop in our bodies in response to antigen Produced by transfer Of antibodies from Another source Natural Passive Immunity Artificial Passive Immunity Natural active immunity Induced Active Immunity Develops after exposure to Antigens (contact with sick Person) Develops after administration to of Antigens to prevent Disease (vaccination) Conferred by transfer of Maternal antibodies across Placenta or breast milk Conferred by administration Of antibodies to combat Infection (immunoglobulin Shot)