Download Immune System Notes.notebook

Immune System Notes.notebook
April 16, 2014
Immune System - fights off infection and pathogens (1)
*Skin is body's first line of defense
-blocks invading pathogens (2)
-BUT skin has some openings
(eyes, nose, mouth, etc.) so
these areas need extra protection.
-secretes oil and sweat making it hard for pathogens
to survive. (3)
* Second line of defense:mucous membranes use hair-like cilia
that are covered in a sticky liquid to try and trap pathogens (4)
*Once a pathogen gets in, immune system relies on the (5)
circulatory system to send chemical signals to coordinate an
attack by transporting specialized cells to the site of infection.
*The immune systems' warriors are proteins and WBCs.
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Immune System Notes.notebook
April 16, 2014
White Blood Cells (WBC)
-their job is to find and kill pathogens
-6 types work together (7)
-different type(s) are used depending on the pathogen
*Basophils - make chemicals that cause inflammation in
the bloodstream
*Mast Cells - makes chemicals that cause inflammation in
other body tissues
*Neutrophils - engulfs pathogens and foreign invaders;
phagocyte
*Macrophage - engulfs dead or damaged body cells and
some bacteria: phagocyte
*Lymphocyte - destroys infected body cells or produces
proteins that inactivate pathogens; 2 types
-T cells: destroy body cells that are infected
with pathogens
-B cells: produce proteins that inactivate
pathogens that have not yet infected a
body cell
*Eosinophil - injects poisonous packets into parasites, such
as protozoa (8)
Phagocytes: cells that destroy pathogens by surrounding
and engulfing them (9)
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Immune System Notes.notebook
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Proteins (10)
-3 different Proteins help the immune system (complement,
antibodies, interferons)
Complement -made by WBC and organs (11)
-weaken a pathogen's cell membrane -causing it to become
hypotonic and burst
-attracts phagocytes to infected area
-cause microbes to stick to walls of blood vessels
-easy to find and destroy by phagocytes
Antibodies -made by B cells, destroy cells in 1 of 3 ways (11)
a) might make pathogen ineffective by binding to the pathogens
membrane proteins
b) might cause pathogens to clump
-makes phagocytes job easier
c) activate complement proteins that
weaken the pathogen's cell membrane
(11)
Interferons -produced by body cells that are infected by a virus
a) cells release interferons that then stimulate uninfected body
cells to produce enzymes that will prevent viruses from
entering/infecting them
b) some stimulate an inflammation response
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Immune System Notes.notebook
April 16, 2014
Immunity prevents a person from getting sick from a pathogen
(12) -can be immune to a pathogen, won't get sick if it invades
your body
-Example: individuals who are heterozygous for sickle
cell-malaria resistance
-2 types of immunity: passive and active
Passive: immunity that occurs without the body undergoing an immune
response (13)
-Can be genetic (transferred through generations via DNA) or
from mother to child through umbilical cord or mother's milk
Active: immunity that your body produces in response to a specific
pathogen that has infected or is infecting your body (13)
-Acquired immunity - occurs after your immune system reacts
to a pathogen invasion, keeps your from becoming sick from a
particular pathogen more than once
-Vaccines are given to help the body reach an acquired
immunity from some pathogens before they have the chance
to attack the body
-Why don't we get an acquired immunity from a common
cold/flu? -viruses mutate very quickly forming new strains
BUT you immune system destroys repeat invaders before
you get sick...You just don't know it!
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Immune System Notes.notebook
April 16, 2014
Immune Response
-Body responds to pathogens in different ways
-responses at the cellular level are called specific defenses;
different for each pathogen
-responses that happen in the same way to every pathogen
are called nonspecific responses; fever and inflammation (14)
Nonspecific responses:
-Inflammation: characterized by swelling, redness, pain,
itching, and increased warmth at the infected site
-happens when pathogen enters the body or when the
body's tissues become damaged
-basophils release chemicals called histamines in
response to pathogen invasions
-histamines cause the blood vessel walls to spread out,
allowing fluids to come and go
-WBCs head to infection site to fight off pathogens,
once defeated swelling stops and tissue repair begins
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Immune System Notes.notebook
April 16, 2014
Nonspecific Response Continued:
-Fever -It's a good thing!
-occurs when mast cells or macrophages release chemicals
causing hypothalamus to raise body temperature
-body temperature returns to normal once the infection is
under control
-Low fevers, less than 100oF, stimulate production of
interferons and increase the rate at which WBC mature
(only mature cells can destroy pathogens) -this helps to
increase the rate at which the body can fight infection.
-High fevers are dangerous
-hypothalamus loses ability to regulate body temp.
-enzymes that control chemical rxns stop functioning
-can cause seizures, brain damage, death
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Immune System Notes.notebook
April 16, 2014
Specific Response:
-leads to acquired immunity, occurs at cellular level
-body must be able to tell the difference between its own
healthy cells and foreign or infected cells
-Antigens: protein markers on the surfaces of cells and
viruses that help immune system identify pathogens (15)
-when a pathogen is detected an immune response is
triggered
-This sometimes involves antibodies that are made for the
specific pathogen, detected by the antigen, that will bind
with the pathogen or clump them together to remove them
-produces an acquired immunity -body produces memory
cells after fighting off the infection.
-memory cells -specialized T and B cells that provide
acquired immunity because they remember an antigen that's
invaded the body before and will quickly attack them. (16)
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Immune System Notes.notebook
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Immune system rejects foreign tissue.
-all cells have protein markers on their surfaces
-body must constantly decide if they are their own or foreign
BUT you don't always want your body to recognize these foreign
cells.
-Blood transfusions or organ transplants
-Tissue rejection occurs when the recipient's immune system makes
antibodies against the protein markers on donor's tissue
-Must determine whether the individuals are compatible before the
procedure can be done
-Recipients take drugs to help decrease the activity of the immune
system
- this makes them more susceptible to pathogens
Autoimmune Disease- immune system loses the ability to recognize
the body's healthy cells and attacks them (17)
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Immune System Notes.notebook
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(18)
Scientists have developed ways to Control Pathogens
1) Maintain a clean environment (19)
2) heat and chemicals kill pathogens outside the body
-antiseptics - kill many different types of pathogens (20)
-Examples: chemicals such as soap, vinegar, and rubbing
alcohol
3) medicines
-antibiotics - target bacteria or fungi and keep them from
growing or reproducing (21)
-target one type
-common practice which
results in antibiotic resistant bacteria
4) vaccines - substances containing the antigen of a pathogen (22)
-cannot cure a person who is sick, but they work to prevent
infection
-allow the development of memory cells and acquired immunity
against an illness without actually getting it; makes antibodies
right away
-you don't get sick because the pathogen is either a weakened
form or dead
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