Ch 31 Immune System & Disease

Ch 31.1 Pathogens & Human Illness We learned about the Black Death (Bubonic Plague) in 7th grade SS. This was a disease transmitted by bacteria that was passed on from host to host by the fleas on rats. This eventually killed 13% of the population at that time in Europe (43+ million people) #1- Why are diseases so important for scientists to study? Write it in your notes. As a table group, discuss Question #1. Be ready to share.

Ch 31 Pathogens & Human Illness DISEASES Infectious Flu, colds, polio …all caused by germs and can be transmitted from person-person Non-infectious Cancer, heart disease… not contagious. Genetics and lifestyle play a role in these.

Ch 31 Pathogens & Human Illness GERM THEORY- (Scientist-Louis Pasteur) specified microorganisms cause diseases. These are called PATHOGENS. In your notes, use pg 941 to record Koch’s Postulates (the 4 conditions must be met before a pathogen is said to be ‘disease-causing’

Ch 31 Pathogens & Human Illness 5 MAJOR TYPES OF PATHOGENS: *1-Bacteria= single celled organisms. Cause illness by releasing chemicals that are toxic to the host, or by destroying healthy cells (ex-food poisoning) *2-Viruses=disease causing DNA & RNA strands which are surrounded by a protein coat. They are very small. Enter & take over a healthy cell causing it to stop its normal functions and instead reproduce more viruses (ex-flu or AIDS) *3-Fungi=Multi or single cellular organisms. They pierce healthy cells and take the nutrients of the cell. Fungi prefer warm, damp conditions (ex-athlete’s foot)

Ch 31 Pathogens & Human Illness 5 MAJOR TYPES OF PATHOGENS: *Protozoa=single celled organisms that take over healthy cells in order to complete their own life cycles. *Parasites= organisms that grow on and feed on a host. Some parasites kill the host and some just drain their resources (ex-mistletoe on trees, worms in animals)

DEADLIEST DISEASES http://www.youtube.com/watch?v=gf2bObJGFkg

Ch 31 Pathogens & Human Illness Pathogens enter the body in different ways (direct or indirect). Direct=physical contact (ex= rabies) Indirect-=pathogens can survive on non-living things until a host comes along (ex…like on your desk!) Airborne Food sources (Mad Cow disease) Vector=anything that carries a pathogen and transmits it to healthy organisms to become infected (ex-bacteria laden fleas…Black Death)

31.2 Immune System Immune system-the body’s way of fighting off infection / pathogens. Healthy cells (white blood cells) and proteins fight infections. Take notes: http://www.youtube.com/watch?v=z3M0vU3Dv8E

31.2 Immune System WBC (white blood cells)-The name comes from this fact: after centrifugation of a blood sample, the white cells are found in the buffy coat, a thin, white layer of nucleated cells btwn the red blood cells & the blood plasma.  Find and kill pathogens 6 main types of WBC (copy the chart at the bottom of pg 946)

31.2 Immune System WBC typical activity when a pathogen enters the body: Basophils (in blood stream) and/or Mast Cells (body tissues) both release chemical signals wh.attract other WBC to the infectious site. (soldiers…we need help! follow me, boys!) If pathogen is a parasite, the WBC, Eosinophils , spray it with poison (Soldiers…Take that, and that!) If pathogen is a virus, bacteria, or fungus, WBC’s Neutrophils and Microphages surround and engulf them (see image next slide) (Cannibalistic (?)Soldiers…we will destroy!)

31.2 Immune System Phagocytosis (engulfing/eating of other cells)

31.2 Immune System After phagocytosis, WBC Lymphocytes initiate specific immune responses: 2 types of Lymphoctyes: T-lymphocytes (T Cells)-destroy body cells that have become infected with the pathogens B-lymphocytes (B Cells)-produce proteins (antibodies) that inactivate pathogens that haven’t infected body cells yet

31.2 Immune System *Antibodies- B Cell proteins destroy pathogens Proteins-the immune system uses 3 kinds of proteins to fight off invading pathogens: *Complement Proteins-made of WBC of specific organs. Some weaken the pathogen’s cell membrane wh allows H20 to enter the cell and causes it to burst. Others attract phagocytes to the infection *Antibodies- B Cell proteins destroy pathogens ‘clump’ pathogens together, making them easier for phagocytes to engulf/destroy Other inactive the pathogen’s proteins wh weaken its membrane *Interferons-proteins which interfere with the entry of pathogens into healthy cells

31.2 Immune System Immunity prevents sickness! Two types of immunity: PASSIVE IMMUNITY-transferred DNA generationally between mother and child. Genetic Immunity -species specific. Some pathogens don’t harm specific species. (ex. Dogs may get distemper, people don’t) Inherited Immunity- antibodies wh pass from mother to child through umbilical cord or breastmilk (colostrum) ACTIVE IMMUNITY- Your body at work, fighting off pathogens that it encounters Acquired Immunity- your body can’t get sick from the same pathogen. Each new illness, is a new pathogen or a mutated version!

Diagnosis…Dogs?? Breath?? IMMUNITY AT IT’S FINEST! http://www.youtube.com/watch?v=ZCfDyv4EJGM http://www.youtube.com/watch?v=CeVtPDjJBPU SKIP THE FIRST 50 SECONDS

31.3 IMMUNE RESPONSE Body responses to pathogens: how does your body handle and recover from pathogen invaders? Specific responses -occur at the cellular level and vary based on the pathogen type and location in the body Non-Specific responses- occur the same for nearly every pathogen (ex. fever, inflammation) INFLAMMATION= swelling, itching, redness, pain, warmth at affected site. Occurs when pathogens enter body or when tissues are damaged Begins when mast cells or basophils release histamines, which cause blood vessels to vasodilate (open and spread out) WBC then squeeze out of the capillaries and move to the infection With defeat of pathogens, inflammation subsides

31.3 IMMUNE RESPONSE Fever (non-specific)- occur when mast cells and/or macrophages release chemicals that cause the hypothalamus (brain)to increase body temp. With defeat of pathogens, cells stop releasing chemicals and fever goes away. Presence of fever in body stimulates interferons, which interfere with virus duplication. Fever also increase WBC production rate High fevers (103+) are dangerous! Hypothalamus can no longer regulate body temp, body enzymes stop functioning and results could include: Seizures, brain damage, even death!

31.3 IMMUNE RESPONSE Specialized Cells produce Specialized Responses! Antigens: protein markers on the surface of cells & viruses. They help identify a pathogen. - Antibodies : are large Y-shaped proteins. They are recruited by the immune system to identify and neutralize foreign objects like bacteria and viruses.

31.3 IMMUNE RESPONSE Humoral Upon pathogen entry, Immune System triggers TWO response: Cellular Humoral *create the chart on the next slide. Use pgs 952-953 to complete the info.

exclusive same exclusive Humoral Immunity Cellular Immunity

31.3 IMMUNE RESPONSE Using the same pages, draw pictures to represent EACH!

31.3 IMMUNE RESPONSE Tissue rejection: occurs when the immune system attacks (makes antibodies) against the protein markers of the new donor tissue. Tissue donors MUST be compatible (same protein markers) or the body will reject the donation. Even for ‘matches’ donor recipients take drugs to suppress their own immune system until the body can adjust to the new organ. Don’t get sick!!