CH. 24 The Immune System

The immune systems consists of organs, cells, and molecules that fight infections and protect us from invaders. Pathogens: Bacteria, Viruses, Parasites, Fungi 1.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 – 1 st 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

31.4 Immunity and Technology Antibiotics and antiseptics cause pathogens to burst.

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

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. E.coli pseudopods

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

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

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

NONSPECIFIC RESPONSES TO PATHOGENS 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

31.4 Immunity and Technology 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 B Cell Activated divide Plasma Cells antibodies

ACQUIRED IMMUNITY B CELLS B Cell Memory B Cell

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

Primary response Secondary response Primary exposure secondary exposure ACQUIRED IMMUNITY- MEMORY CELLS The next time this memory cell sees this antigen:

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

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

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

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

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

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 Research and answer questions on separate paper or print answers.

Immunity Acquired Innate Acquired resistance to infection Inborn resistance to infection Active ImmunityPassive Immunity Produced by antibodies that develop in our bodies in response to antigen Produced by transfer Of antibodies from Another source Natural active immunity Induced Active Immunity Natural Passive Immunity Artificial Passive 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)