1. Fighting the Enemy Within! Immune / Lymphatic System
phagocytic leukocyte
Fighting the Enemy Within!
Immune / Lymphatic System
lymphocytes
attacking
cancer cell
lymph
system

2. Avenues of attack Points of entry Routes of attack _________
respiratory system
______________
break in skin
Routes of attack
_____________
lymph system

3. What’s in your lunchbox?
Why an immune system?
Attack from outside
animals must defend themselves against invaders (pathogens)
______________
HIV, flu, cold, measles, chicken pox
bacteria
pneumonia, meningitis, tuberculosis Lyme disease
yeast (“Athlete’s foot”…)
protists
amoeba, malaria
Attack from inside
_______________________
Mmmmm,
What’s in your lunchbox?

4. Lymph system Production & transport of leukocytes
Traps foreign invaders
Lymph system
lymph vessels
(intertwined amongst blood vessels)
lymph node

5. Bacteria & insects inherit resistance. Vertebrates acquire immunity.
Lines of defense
1st line: ___________________
broad, external defense
“walls & moats”
skin & mucous membranes
2nd line: ________________
broad, internal defense
“patrolling soldiers”
leukocytes = phagocytic WBC
3rd line: _________________
specific, acquired immunity
“elite trained units”
lymphocytes & antibodies
B cells & T cells
Bacteria & insects inherit resistance.
Vertebrates acquire immunity.

6. 1st line: Non-specific External defense
Barrier
skin
__________
mucous membranes, cilia, hair, earwax
Elimination
coughing, sneezing, urination, diarrhea
______________
stomach acid, sweat, saliva, urine
Lining of trachea: ciliated cells & mucus secreting cells

7. 2nd line: Non-specific patrolling cells
bacteria
Patrolling cells & proteins
attack pathogens, but don’t “remember” for next time
leukocytes
phagocytic white blood cells
macrophages, neutrophils, natural killer cells
complement system
proteins that destroy cells
inflammatory response
increase in body temp.
increase capillary permeability
attract macrophages
macrophage
yeast

8. Leukocytes: Phagocytic WBCs
Attracted by chemical signals released by damaged cells
ingest pathogens
digest in lysosomes
_______________
most abundant WBC (~70%)
~ 3 day lifespan
“big eater”, long-lived
______________
destroy virus-infected cells & cancer cells

9. Destroying cells gone bad!
Natural Killer Cells perforate cells
________________________
insert into membrane of target cell
forms pore allowing fluid to flow in & out of cell
cell ruptures (lysis)
apoptosis
vesicle
natural killer cell
perforin
cell membrane
perforin punctures cell membrane
cell membrane
virus-infected cell

10. Inflammatory response
Damage to tissue triggers local non-specific ___________________________
release chemical signals
capillaries dilate, become more permeable (leaky)
delivers macrophages, RBCs, platelets, clotting factors
______________________
decrease bacterial growth
stimulates phagocytosis
speeds up repair of tissues

11. Fever When a local response is not enough ___________________________
higher temperature helps defense
_____________________
stimulates phagocytosis
________________________
causes liver & spleen to store iron, reducing blood iron levels
bacteria need large amounts of iron to grow
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.

12. 3rd line: Acquired (active) Immunity
Specific defense with memory
_________________
B cells
T cells
antibodies
Responds to…
_____________
cellular name tags
specific pathogens
specific toxins
abnormal body cells (cancer)
B cell

13. How are invaders recognized?
Antigens
cellular name tag proteins
________________
no response from WBCs
_________________
response from WBCs
pathogens: viruses, bacteria, protozoa, parasitic worms, fungi, toxins
non-pathogens: cancer cells, transplanted tissue, pollen
“self”
“foreign”

14. Lymphocytes B cells T cells “Maturation” humoral response system
bone marrow
Lymphocytes
B cells
humoral response system
_______________
T cells
cellular mediated response system
_________________
“Maturation”
learn to distinguish “self” from “non-self” antigens
if react to “self” antigens, cells are destroyed during maturation
Tens of millions of different T cells are produced, each one specializing in the recognition of oen particar antigen.

15. B cells
Attack, learn & remember pathogens circulating in blood & lymph
Produce specific ___________ against specific __________
Types of B cells
__________________
immediate production of antibodies
rapid response, short term release
memory cells
continued circulation in body
long term immunity

16. Antibodies Proteins that bind to a specific antigen Y Y Y Y Y Y Y Y Y
binding region matches molecular shape of antigens
each antibody is unique & specific
tagging “handcuffs”
“this is foreign…gotcha!” Y Y Y
antigen- binding site on antibody
antigen Y Y Y Y
variable binding region Y Y
each B cell has ~50,000 antibodies

17. What do antibodies do to invaders?
neutralize
capture
precipitate
apoptosis
macrophage eating tagged invaders
invading pathogens tagged with antibodies Y

18. invader (foreign antigen)
10 to 17 days for full response
B cell immune response
B cells + antibodies Y
invader (foreign antigen)
tested by B cells
(in blood & lymph)
memory cells
“reserves” Y Y
recognition Y
captured invaders
macrophage Y
clones
1000s of clone cells
plasma cells
release antibodies Y Y

19. Vaccinations Immune system exposed to harmless version of pathogen
________________________________________________________________
“active immunity”
rapid response on future exposure
creates immunity without getting disease!
_______________

20. Passive immunity Obtaining antibodies from another individual
_________________
antibodies pass from mother to baby across placenta or in mother’s milk
critical role of breastfeeding in infant health
mother is creating antibodies against pathogens baby is being exposed to
_______________
injection of antibodies
short-term immunity

21. What if the attacker gets past the B cells in the blood & actually infects (hides in) some of your cells?
You need trained assassins to recognize & kill off these infected cells!
Attack of the Killer T cells! T
But how do T cells know someone is hiding in there?

22. T cells Attack, learn & remember pathogens hiding in infected cells
recognize antigen fragments
also defend against “non-self” body cells
cancer & transplant cells
Types of T cells
___________
alerts rest of immune system
___________________
attack infected body cells
_______________
long term immunity
T cell attacking cancer cell

23. Attack of the Killer T cells
Destroys infected body cells
binds to target cell
______________________
punctures cell membrane of infected cell
apoptosis
vesicle
Killer T cell
Killer T cell binds to infected cell
cell membrane
perforin punctures cell membrane
cell membrane
infected cell
destroyed
target cell

25. Immune system & Blood type
antigen on RBC
antibodies in blood
donationstatus A
type A antigens on surface of RBC
anti-B antibodies __ B
type B antigens on surface of RBC
anti-A antibodies AB
both type A & type B antigens on surface of RBC
no antibodies
universal recipient O
no antigens on surface of RBC
anti-A & anti-B antibodies
universal donor
Matching compatible blood groups is critical for blood transfusions
A person produces antibodies against foreign blood antigens