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Aim: How does our body come under attack?
What is a disease?
Disease is any condition that prevents the body from working as it should.
As a result the body may fail to maintain homeostasis.
What can cause disease?
GeneticsGeneticsLifestyle choicesLifestyle choices
PathogensPathogensOrgan malfunctionOrgan malfunction
ToxinsToxins
What are pathogens?
Foreign Invaders!Foreign Invaders!(not aliens)
Types of Pathogens
• Bacteria
• Viruses
• Fungi
• Parasites
BacteriaBacteria
• Prokaryotes
(no nucleus, missing organelles)
• Unicellular (one cell)
Examples:• Strep throat• Salmonella
• Syphilis (STD)
How can we treat bacterial infections?How can we treat bacterial infections?
Antibiotics are drugs used to stop infections by bacteria.
Antibiotics will not workagainst viruses!!
SuperBugs!!
Virus• A VIRUS IS NOT A CELL (IT IS NOT ALIVE)
• Made of: DNA + a Coat around it
They can only reproduce INSIDE a cell.
A virus works by injecting its DNA into YOUR cells and hijacking them
It turns your cell into a virus producing factory… then causes it to explode when it’s done!
They can only reproduce INSIDE a cell.
A virus works by injecting its DNA into YOUR cells and hijacking them
It turns your cell into a virus producing factory… then causes it to explode when it’s done!
Viruses are GRIMEY
Examples• HIV
• Chicken Pox• Influenza (the flu)
Fungus
• Athlete’s foot• Ring worm
What can the doctorPrescribe?
Anti-fungal medicine
Parasites
Some animals and one-celledorganisms survive by livingand feeding on other organisms (their host).
Example: tapeworms and heartworms
How do pathogens get in your body?How do pathogens get in your body?
AirAir ContactContact
WaterWaterBlood & bodily fluid
Blood & bodily fluid
Diagnosing – determine the disease you have
Diagnosis is made based on symptoms and an examination
Prevention vs. Treatment Prevention vs. Treatment
Prevention – ways to avoid getting the disease.
Treatment – ways to help people with a disease to get better.
Aim: How does our body defend us from pathogens?
Flu attack!
1st Line of Defense1st Line of Defense
• Skin• Mucus• Hair• Tears in eyes• Acid in stomach
2nd Line of Defense2nd Line of Defense
The Immune System
• Made of proteins, cells, and tissues that identify and defend the body against foreign chemicals and organisms
White Blood cellsWhite Blood cells
• Warrior Cells! • Defenders of the body• Eat the bad guys to
destroy them
How does our immune system identify pathogens?
• A ID tag made of proteins identifies the invader as foreign
• This ID tag is called an antigen.
AntigenAntigen
What happens after we identify the foreign invader?
What happens after we identify the foreign invader?
Our body makes antibodies, which are their weapons against the foreign antigens.
Antibodies are Y-shaped weapons
Antibodies Antibodies
Pathogen
Antigens
Antibodies
Antibodies find the Antigens on the pathogen & targets it for destruction !
How do antibodies destroy pathogens?
• When the antibody attaches to the antigen, it tears open the bad guy’s (pathogen’s) cell membrane– and the bad guy dies!!!
• It also tells your immune system cells that this guy is ready to be eaten alive!
How are locks & keys similar to antigens and antibodies?
Antibodies are made specifically to match the shape of the antigen.
Antibodies are made specifically to match the shape of the antigen.
Antibody vs. AntigenAntibody vs. Antigen
Antibody – weapon found in your body
Antigen – ID tag found on the pathogen
• Our immune system “remembers” bad pathogens it has fought in the past
• It has weapons built up so the next time the pathogen enters your body, you are ready to defend yourself!
Our Immune System has a good memory!
Our Immune System has a good memory!
The second response to the same pathogentriggers a quicker andstronger response.
** After the first response, the immune system “remembers”specific pathogens by leaving behind cells that protect thebody for years (memory cells).
DO NOW: What is immunity?
Immunity: When a person is protected from getting a certain disease.
Survivor- Tribal Immunity
Aim: How does your body become immune to disease?
Farms & Better Immune systems
Types of ImmunityTypes of Immunity
From motherFrom mother
Making your own antibodies to attack pathogensMaking your own antibodies to attack pathogens
VaccinesVaccines
How was the first Vaccine developed?
English physician Edward Jenner developed an inoculation against smallpox in 1796. Armed with the knowledge that milkmaids who had been exposed to cowpox, a relatively mild affliction, didn't come down with smallpox, Jenner intentionally infected an eight-year-old boy with cowpox. Two months later he infected the boy again, this time with smallpox. As Jenner expected, the child didn't come down with the disease -- he was immune.
What is a vaccine?
A vaccine is a dose of a pathogen destroyed so it is no longer harmful, but it still has the antigens present.
WeakenedPathogen
Antigen
Antibody
These antigens trigger an immune response.
How do scientists make vaccines?• http://www.pbs.org/wgbh/nova/bioterror/v
accines.html
1) Obtain pathogen2) Treat pathogen to
kill or weaken it.3) Inject altered
pathogen (vaccine) into organism.
4) Body responds to antigens by making antibodies & having cells attack invader.
5) Some white blood cellsremain in thebody to protect the organismfrom future attacks.
What happens when you get invaded by the real pathogen?
Memory Cells are already present and will multiply quickly and destroy the invader before it has the chance to cause the disease.
MemoryCells
Immune response
An
tib
od
y C
on
cen
trat
ion
Time
First exposure
Second exposure
Interval between exposures
Vaccine
Real Pathogen
BioterrorismToday there is mounting concern about the threat of a bioterrorist attack using smallpox -- so much concern that in October 2001 the American government decided to order enough vaccinesvaccines to protect every U.S. citizen.Smallpox has a fearsome reputation, having killed more people in history than any other infectious disease.
Aim: How can the immune system malfunction?
How can your immune system malfunction?
1. Allergies2. Asthma3. Autoimmune Disease4. Organ Transplants
What is an allergy?
• An allergy is a quick immune system reaction to substances that are normally harmless
• Can you think of materials that can cause allergic reactions?
What are things that cause allergies?
HOUSE DUST
BEE POLLEN
MOLD
RAGWEED
Allergens
Allergic reactions
•Histamines are chemicals that cause inflammation
•Inflammation: blood vessels get larger to send blood to area. You get Itchy, warm, red.
•Hives, nausea, or shock•What can we take for allergies?
https://www.youtube.com/watch?v=sqrnShjM4II&spfreload=10
Asthma is an allergic reaction
• Allergic reaction that causes your respiratory system to swell up – you cant breathe well
https://www.youtube.com/watch?v=7EDo9pUYvPE
Autoimmune disease
The immune System mistakes your own cells for the bad guys, and attacks them!
Ex: Diabetes, Multiple Sclerosis
https://www.youtube.com/watch?v=M7O78LvrNSQ
Why are organ transplants difficult?Why are organ transplants difficult?
• This is a kidney being removed from a donor
• The donor will have his own ID tags on the cell membrane. What are these ID tags called?
Antigens!Antigens!
How will the recipient react?How will the recipient react?
• A transplanted organ is recognized as foreign and is attacked by the immune system (REJECTION).
• The chance of REJECTION is less when the donor and recipient are closely related or when anti-rejection medication is used.
