Download 6.3 Immune system notes

6.3 Defense against Infectious Disease
Pathogen – any living organism or virus that is capable of causing a disease.
Pathogens include viruses, bacteria, protozoa, fungi and worms.
Most of the pathogens we are exposed to never get into our bodies.
Primary Defense
Ways of making it difficult for pathogens to enter the body
Skin – contains two primary layers, dermis and epidermis.
The underneath layer is dermis and it is alive, the top layer is the epidermis and it
is mainly dead cells.
This top layer of epidermis is an excellent barrier against most pathogens.
Entry points that are not covered by skin are covered by mucus membranes.
Mucus traps incoming pathogens to prevent them from reaching cells.
Some mucus membranes are covered with cilia which are hair-like projections
that move trapped pathogens out of the body.
Locations of mucus membranes
Trachea – the tube that carries air to and from the lungs
Nasal passages – tubes that allow air to enter the nose and then the trachea
Urethra – a tube that carries urine from the bladder to the outside
Vagina – the reproductive tract leading from the uterus to the outside
Blood clotting
When the skin is damaged, exposing an opening for pathogens, blood will clot.
This prevents further blood loss and it plugs the opening to prevent pathogens
from gaining access.
In the blood plasma there are different plasma proteins with different functions.
Two of the proteins are involves in clotting of the blood.
Prothrombin and Fibrinogen
Proteins always in the plasma but “inactive”.
Also in the plasma are cell fragments called platelets.
Platelets form in bone marrow and break apart into several fragments, they have
no nucleus and are very short lived (8-10 days)
If blood vessel is damaged, the cells release chemicals that cause platelets to
adhere to damaged area.
The damaged cells and the platelets release chemicals called clotting factors that
convert the prothrombin in the blood to thrombin.
Thrombin is an enzyme that catalyzes fibrinogen to fibrin, which is insoluble and
helps to form a plug.
Immune Response
When a _______________ does get into the body, it causes an immune response.
If it’s the first time the particular pathogen has been in the body, it’s called a
____________ immune response, if not the first time, it’s called a ____________
immune response.
Primary response can take more than a _________ to be successful, secondary
response is very quick with little symptoms. “______________”.
Phagocytes (non-specific response)
A type of leucocyte (white blood cell) that is involved early in the immune
response is a ________________. (Phagocyte)
Macrophages are _________ and can change _________ to easily squeeze in and
out of the blood and engulf pathogens by ________________.
Macrophages can recognize a cell as being “_______” or “_________” based on
cell membrane surface ____________.
This is a ___________________ response.
Specific Response
___________________ are proteins produced by the body in response to a
specific pathogen.
Each antibody is ______________ because each pathogen is different.
Pathogens are cells with membranes that contain proteins, or viruses with a
protein coat called a ____________.
These foreign proteins are called _____________.
Antibodies
Antibodies are _______________ proteins.
At the ends of the forks are binding sites at attach to the _____________.
Antibodies are produced by a type of leucocyte called a ________________.
There are many different types of plasma cells, and each type can only produce
________________ of antibody.
Primary Immune Response
A specific _____________ is identified
A specific _____________ is identified to produce an antibody against the
pathogen
The specific plasma cell begins ____________ itself to make many
Plasma cells begin making ______________
Antibodies circulate in __________ until they find pathogen
In various ways, antibodies _____________ pathogen
Some plasma cells remain in blood to provide immunity against secondary
infection. (________________)
Memory plasma cells respond quickly if same pathogen encountered again.
(_____________________________________)
HIV
HIV is the abbreviation for a virus called the _________ _____________ ______.
Like all ____________, it has a specific type of cell it likes to infect
HIV attacks a type of __________________ in our immune system.
The immune system slowly loses the ability to make _______________.
AIDS
AIDS ( _____________ ____________ ____________ _________) is the name of
the disease caused by HIV.
Symptoms don’t show for ____________ after the initial HIV infection.
With the immune system not working properly, the infected person becomes
infected with multiple infections.
No cure, but medicines exist that can ___________ _____ _______ period
between infection and symptoms.
Transmitted most commonly through ________________ and sharing ________.
Sometimes transmitted from HIV+ mother to child during ______________ or
_____________________.
Initially spread by blood transfusions.
Antibiotics
Bacteria are _____________ organisms, humans are ____________.
Antibiotics are ______________ that take advantage of the differences and block
some of the ________________ of bacteria. ( certain reaction, cell wall
production etc)
Viruses have no ____________ _________ so antibiotics don’t work on them.
Antibiotic Resistance
Because of genetic _________, high numbers and very fast _____________ times,
a bacterium with a genetic ___________ causing it to not be affected is possible.
That bacterium can then produce large numbers of bacteria resistant to a
particular antibiotic.
Odds are increases by long-term use and overuse. (S. aureus has become
_________)