Transcript specific, previously encountered

Non-Specific
Defenses
April 1-4, 2016
Do Now
List the body parts & processes that
protect us from disease.
Body fights disease in 2 ways
1. Non-specific defense system
 Protects body from all foreign substances
2. Specific defense system (aka immune
system)
 Attacks particular, previously
encountered foreign substances
Try to organize the list from the do
now into the two systems – we will
double check later!
Today, we are focusing
on nonspecific
defenses. Next class:
Immune system
Surface Barriers
Skin and mucus membranes prevent
pathogens from entering body




Tightly bound cells provide physical barrier
Acidic secretions in skin, vagina, and stomach
inhibit bacterial growth
Mucus in respiratory and digestive tracts trap
bacteria
Saliva and tears contain an enzyme – lysozyme
– that destroys bacteria.
Cellular Defenses
The body has specialized cells that destroy
foreign material
 Phagocytes
(macrophages & neutrophils) –
engulf and digest foreign particles, such as
bacteria and viruses
Cellular Defenses
The body has specialized cells that destroy
foreign material
 Phagocytes
(macrophages & neutrophils) –
engulf and digest foreign particles, such as
bacteria and viruses
 Natural
killer cells (a type of lymphocyte) –
destroy cancer / virus infected cells by
releasing chemicals that destroy cell
membranes.
Watch
me!
Watch
me 2!
Inflammation
Inflammation occurs when an area that is
damaged or infected becomes red, warm,
swollen, and painful.
Occurs when damaged cells release
chemicals that increase blood flow, make
blood vessels leaky, and attract leukocytes.
How does it protect the body?


prevents spread of pathogens to nearby
tissue
helps rid body of pathogens and dead cells
 Helps
speed healing
Fever
Fever is when the body’s temperature
becomes elevated due to infection
Occurs when white blood cells release
chemicals that reset the body’s thermostat
How does it protect the body?

reduces bacterial growth by causing the
liver & spleen to take up nutrients

increases metabolic rate to speed the
healing process
Why do we get the
chills when we have a
fever?
Turn and Talk
Review the list of defenses we made during
the do now and categorize them as
specific or non-specific defenses.
Then, review for exit ticket!
Exit Ticket
1.
Which of these describes NK (natural killer)
cells?
a)
b)
c)
d)
Immune cells that release chemicals to kill
specific, previously encountered pathogens
Immune cells that release chemicals to kill any
pathogen it encounters
Immune cells that engulf and destroy specific,
previously encountered pathogens
Immune cells that engulf and destroy any
pathogen it encounters
Exit Ticket
2.
Which of these does not characterize the
inflammatory response?
a) blood capillaries become leaky
b) affected areas become warm and red
c) reduces nutrients available to pathogens
d) speeds healing
Exit Ticket
3. How does a fever help the body fight disease?
a) by raising body temperature above the
tolerance of pathogens
b) by decreasing the nutrients available to
pathogens
c) by reducing pathogen’s metabolic rate
d) by increasing blood flow to infected
areas
Exit Ticket
3. How does a fever help body fight disease?
a) by raising body temperature above the
tolerance of pathogens
b) by decreasing the nutrients available to
pathogens
c) by reducing pathogen’s metabolic rate
d) by increasing blood flow to infected
areas
Exit Ticket
4.
Describe three ways the skin and mucus
membranes fight disease (2 are required, one
is EC)
Extra credit: Name a phagocyte