Transcript Regents Biology - Explore Biology

phagocytic
leukocyte
“Fighting the
Enemy Within”
Immune System
AP Biology
lymphocytes
attacking
cancer cell
lymph
system
2006-2007
Avenues of attack
 Points of entry
digestive system
 respiratory system
 urogenital tract
 break in skin

 Pathways for attack
circulatory system
 lymph system

Regents Biology
Why an immune system?
 ___________________________________
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lots of organisms want you for lunch!
we are a tasty vitamin-packed meal
 cells are packages of macromolecules
 no cell wall
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___________________________________
 _____________________
 HIV, flu, cold, measles, chicken pox, SARS
 _____________________
 pneumonia, meningitis, tuberculosis
 _____________________
 yeast
 _____________________
 amoeba, Lyme disease, malaria

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What’s for
lunch?!
How are invaders recognized?
 ____________________________________
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 “self” vs. “invader”
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”
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Lines of defense
 ____________________________

broad, external defense
 “walls & moats”

____________________________
 ____________________________
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broad, internal defense
 “patrolling soldiers”

____________________________
 ____________________________
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specific, acquired immunity
 “elite trained units”

____________________________
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 B & T cells
1st line: Physical Barriers
 non-specific defense
 external barrier

___________________
___________________
___________________
___________________
 ____________________
 ____________________
 respiratory system
 digestive system
 urinary system
 genitals
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Lining of trachea:
ciliated cells &
mucus secreting
cells
1st line: Chemical barriers on skin
 Skin & mucus membrane secretions

____________________
 pH 3-5

____________________
 pH 2

____________________
 washing action

____________________
 traps microbes

____________________
 anti-bacterial = “lick your wounds”
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anti-microbial proteins
 lysozyme
 digests bacterial cell walls
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2nd: Generalist, broad range patrols
 Patrolling ________________________

__________________________________
 _____________________________________
 surface name tag

phagocyte cells
 ____________________
 “big eaters”
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Macrophage “eating” bacteria
Lymph system
Production of white blood cells &
traps “foreign” invaders
lymph vessels
(intertwined amongst blood vessels)
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2nd
“circulatory” system
lymph node
Phagocytes
macrophage
bacteria
white blood cells that eat
macrophage
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yeast
Why do injuries swell?
 Inflammation

injured cells release chemical signals
Pin or splinter
 histamines
 increases blood
flow
 brings more
white blood
cells to fight
bacteria
 brings more red
blood cells &
clotting factors
to repair
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Bacteria
Blood clot
Swelling
Chemical
alarm
signals
Phagocytes
Blood vessel
Fever
 When a local response is not enough

full body response to infection

raises body temperature

higher temperature helps in defense
 slows growth of germs
 helps macrophages
 speeds up repair of tissues
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3rd line: Lymphocytes
 Specific defense

responds to specific
invaders
 recognizes specific
foreign antigens
 ___________________________
 ___________________________
___________________________
 ___________________________
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B cell
B cells & antibodies
 ___________________________
white blood cells that attack
invaders in blood
 mature in Bone marrow
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 Plasma B cells
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 Memory B cells
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can make antibodies quickly the next time
 protects you from getting disease more than once
Regents Biology
Antibodies
 Proteins made by B cells that tag invaders
in the blood so macrophages can eat them

tag says “this is an invader”  gotcha!
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B cells
releasing antibodies
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invading germs tagged
with antibodies
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macrophage
eating tagged invaders
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B cells immune response
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“reserves”
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recognition
B cells
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B cells
release
antibodies
patrol blood
forever
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(foreign antigen)
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invader
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10 to 17 days
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Vaccinations
 ____________________________________
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
rapid response if
future exposure
 Most successful
against viral diseases
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1914 – 1995
Jonas Salk
 Developed first vaccine

against polio
April 12, 1955
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Polio epidemics
1994:
Americas polio free
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Protecting you from disease
 Vaccinations

advantage
 don’t get illness
 long term immunity
 produce antibodies for life
 works against many viruses
& bacteria

IMPORTANT
PROTECTION
 disadvantage
 not possible against all invaders antibodies pass
from mother to
Breastfeeding
baby in breast
milk
 mother’s milk gives baby
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antibodies & keeps baby healthy
What if the attacker gets past
the B cells in the blood &
infects some of your cells?
You need trained assassins
to kill off these infected cells!
T
AP Biology
Attack
of the
Killer T cells!
2006-2007
T cells
 T cells mature in Thymus
 Helper T cells

sounds the alarm for rest
of immune system
 Killer T cells

_____________________________
 Memory T cells

remembers invader & reacts
against it again quickly
Where’s that?
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Thymus
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Attack of the Killer T cells
 __________________________________
T cell binds to invaded cell
 secretes perforating protein

 punctures cell membrane of infected cell
 cell bursts
Killer T cell
Vesicle
Cell
membrane
Perforin
punctures
cell membrane
Cell
membrane
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Invaded cell
Immune response
invader
skin
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invaders infect cells
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invaders in blood
skin
Protecting you from disease
 _____________________________

advantage
 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)
 can get sick again
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Immune system malfunctions
 __________________________

immune system attacks own cells
 lupus
 antibodies attack many different
body cells
 rheumatoid arthritis
 antibodies causing damage to
cartilage & bone
 diabetes
 beta-islet cells of pancreas
attacked & destroyed
 multiple sclerosis
 T cells attack myelin sheath of
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brain & spinal cord nerves
Immune system malfunctions
 Allergies

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 allergens
 proteins on pollen
 proteins from dust
mites
 proteins in animal
saliva
 body mistakenly
thinks they are
attackers
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Diseases of the immune system
 HIV: Human Immunodeficiency Virus
__________________________
 helper T cells can’t activate rest of
immune system

 body doesn’t hear the alarm
 AIDS:
Acquired ImmunoDeficiency Syndrome
__________________________
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 death usually from other
invading diseases or cancer

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How to protect yourself…
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It’s safe
to ask Questions!
AP Biology
2006-2007