1. “Fighting the Enemy Within” http://www.youtube.com/watch?v=lrYlZJiuf18
phagocytic leukocyte
Immune System
lymphocytes
attacking
cancer cell
lymph
system

2. Avenues of attack Points of entry Pathways for attack
digestive system – mouth – saliva/acid
respiratory system – nose – hairs/mucus
urinary system – urethra (shorter in females)
genitals
break in skin – cut
eyes
Pathways for attack
circulatory system
lymph system
= How pathogens move around your body

3. Why do we need an immune system?
Attack from the outside & inside
cells are packages of proteins, carbohydrates & fats
no cell wall – plasma membrane – semi permeable
organisms must defend themselves against (pathogens) invaders
viruses – NOT LIVING ( )
HIV, flu, cold, measles, chicken pox, SARS
bacteria
pneumonia, meningitis, tuberculosis, strep throat
fungi
yeast, ringworm, athlete’s foot
protists
amoeba (disentary) , Lyme disease, malaria
cancer cells – come from within
abnormal body cells – “starve” healthy cells

4. How are invaders recognized?
Antigens
chemical name tags on the surface of every cell – Protein
“self” vs. “invader” – ALL BASED ON SHAPE
one of your own cells
disease-causing virus
disease-causing bacteria
antigens say: “I belong here”
antigens say: “I am an invader”
antigens say: “I am an invader”

5. 1st line: Physical Barriers
non-specific defense
external barriers
skin & mucus membranes
excretions
sweat
stomach acid
tears
mucus
saliva
“lick your wounds”
Lining of trachea: ciliated cells & mucus secreting cells

6. 2nd: Generalist, broad range patrols
White blood cells
attack invaders that get through the skin
recognize invader by reading antigen
surface name tag – BASED ON SHAPE
phagocyte cells
macrophages
“big eaters” that engulf via
endocytosis, then fuse with
lysosome, and finally exocytosis)
Macrophage “eating” bacteria

7. Why do injuries swell?
Inflammation - injured cells release chemical signals
histamines
increases blood flow (red and warm)
brings more white blood cells to fight bacteria (pus)
brings more red blood cells & clotting factors to repair

8. Fever When a local response is not enough
full body response to infection
raises body temperature – 37 C or 98.6 F
TOO high = dangerous
higher temperature helps in defense
slows growth and metabolism of pathogens
helps macrophages
speeds up repair of tissues
Certain bacterial infections can induce an overwhelming systemic inflammatory response leading to a condition known as septic shock.
Characterized by high fever and low blood pressure, septic shock is the most common cause of death in U.S. critical care units.
Clearly, while local inflammation is an essential step toward healing, widespread inflammation can be devastating.

9. 3rd line: Lymphocytes Specific defense responds to specific invaders
B cell
Specific defense
responds to specific invaders
recognizes specific foreign antigens
white blood cells
B cells & antibodies
T cells

10. B cells & antibodies ACTIVE IMMUNITY
white blood cells that attack invaders in blood
mature in Bone marrow
Patrolling B cells
make antibodies against invader immediately
Memory B cells
remembers invader
can make antibodies quickly the next time
protects you from getting disease more than once

11. Antibodies
Proteins made by B cells that tag invaders in the blood so macrophages can eat them
tag says “this is an invader”  gotcha!
biological “handcuffs”
antibody attaches to antigen of invader – they “FIT” Y
invading germs tagged with antibodies
B cells releasing antibodies Y Y
macrophage eating tagged invaders

12. B cells immune responseY
B cells immune response Y
B cells
release antibodies
patrol blood
forever
invader (foreign antigen) Y Y
“reserves”
memory B cells Y
B cells
recognition
Antibody “fits” with antigen Y Y
10 to 17 days

13. B Cells T Cells

14. Vaccinations Jonas Salk
Exposure to harmless version (“dead”, weakened, or part) of a pathogen (“germ”)
stimulates immune system to produce antibodies to invader - ACTIVE IMMUNITY
rapid response if future exposure
Most successful against viral diseases
Ex: flu, chicken pox, HPV,
MMR, swine flu, whooping
cough, polio, small pox
Jonas Salk
Developed first vaccine
against polio

15. Curing you of disease Antibiotics = medicine advantage disadvantage
kill bacteria that have successfully invaded you
make you well after being sick
disadvantage
use only after sick
only good against bacteria
possible development of resistance by bacteria (if don’t use correctly) – ALWAYS TAKE THE ENTIRE Rx
can get sick again

16. Diseases of the immune system
HIV: Human Immunodeficiency Virus
infects helper T cells
helper T cells can’t activate rest of immune system
body doesn’t hear the alarm
AIDS: Acquired ImmunoDeficiency Syndrome
immune system is weakened
infections by other diseases
death from other invading diseases or cancer

17. Immune system malfunctions
Auto-immune diseases
immune system attacks own cells
lupus
antibodies attack many different body cells
rheumatoid arthritis
antibodies causing damage to cartilage & bone
diabetes
insulin-making cells of pancreas attacked & destroyed
multiple sclerosis
T cells attack myelin sheath of brain & spinal cord nerves
fatal

18. Immune system malfunctions
Allergies
produce histamines
over-reaction to harmless antigens
allergens
proteins on pollen
proteins from dust mites
proteins in animal saliva
body mistakenly thinks they are harmful attackers (antigens)

19. http://www.youtube.com/watch?v=lrYlZJiuf18 Watch the video again…
Can you see the flow or steps to an Immune Response?