Chapter 14 Flashcards
The human body has evolved a complex system of defenses to fight
pathogens (organisms that cause disease) and keep us healthy
What is one way the immune system defends the body in a nonspecific way?
by attacking anything foreign
The immune system can also identify
certain invading cells and attack them specifically
The nonspecific immune system consists of
2 lines of defense
the 1st and 2nd line of defense
First Line of Defense
a barrier that helps prevent pathogens from entering the body.
First Line of Defense :
The body has several different types of barriers
skin- blocks pathogens
mucous membranes- release mucus to trap microbes
cilia- in the respiratory system, sweeps out mucus with it’s trapped microbes
stomach acid- kills germs that enter through the nose and mouth
Microbes that get into the body encounter the
second line of nonspecific defense
-it’s not meant to limit the spread of invaders in advance of specific immune responses
How many types of immune responses are there?
inflammatory response
phagocytes
interferons
Inflammatory response
characterized by swelling, redness, soreness, and increased warmth in the area
What is the purpose of the inflammatory response?
to increase the blood supply to the area, thus increasing nutrients - including oxygen and white blood cells to fight disease
How does the inflammatory response work?
histamine and increased body temperature
Histamine
triggers vasodilation (enlargement of blood vessels), which increases blood supply to the area bring more phagocytes to gobble up germs
Histamine is also responsible for the symptoms of the
common cold: sneezing, coughing, redness, and itching and runny nose and eyes- all in attempt to get rid of the body of invaders
Increased body temperature speeds up the
immune system and makes it more difficult for microbes to function
Phagocytes
also consume invading microbes
Macrophages (‘giant’ eaters’)
a type of white blood cell that extend psuedopods and engulf huge numbers of microbes over a long period of time
Interferons
these chemicals are released by the immune system to block against viral infections
The 3rd line of defense is
specific and consists of lymphocytes
2 types of lymphocytes
B lymphocytes and T lymphocytes
- both originate in the bone marrow
- both cell types circulate in the blood, lymph, and lymphatic tissue: spleen, lymph nodes, tonsils, and adenoids
- both recognize different specific antigens (germs)
Antigen
anything that triggers an immune response
B lymphocytes
produce antibodies against a specific antigen in what is called a humoral response
T lymphocytes
fight pathogens by hand-to-hand combat in what is called a cell-mediated response
Antibodies are part of the 3rd line of defense- the specific immune response.
Each antibody has the ability to
bind to only one particular antigen
Antibodies angainst influenza bind to and only
neutralize the influenza virus; they have no effect on the polio virus
Antibodies neutralize antigens by
binding to them and by forming an antigen-antibody complex that can then be consumed by a phagocyte
Clonal selection
a fundamental mechanism in the development of immunity
-antigens that have entered the body bind to specific B or T lymphocytes
Once a lymphocyte has been slected,
it becomes very metabolically active, proliferates (clones 1000s of copies of itself) and differentiates into plasma cells and memory cells
Once a lymphocyte has been slected,
it becomes very metabolically active, proliferates (clones 1000s of copies of itself) and differentiates into plasma cells and memory cells
Plasma cells
these fight antigens immediately in what is called the primary immune response
they don’t live long
Plasma cells
these fight antigens immediately in what is called the primary immune response
they don’t live long
Memory cells fight the same antigens that plasma cells do, but they
remain circulating in the blood in samll numbers for a lifetime
You have memory cells circulating in your blood that are specific
for every viral infection you have every been ill with and every disease against which you have been vaccinated
You have memory cells specific for
mumps, measles, rubella, and polio
You have memory cells specific for
mumps, measles, rubella, and polio
Immunological memory
- the capacity of the immune system to generate a 2ndary immune response
- it’s the mechanism that prevents you from getting any specific viral infection, such as chicken pox, more than once
Types of immunity
passive and active immunity
Passive immunity
temporary
- antibodies are borrowed and don’t survive for long
- ex. maternal antibodies that pass through the placenta to the developing fetus or that pass through breast milk to the baby.
The first milk that a newborn receives from the mother is called
colostrum and is 100% antibodies
Active immunity
present
- you make the antibodies yourself
- an individual makes his or her own antibodies after being ill and recovering or after being given an immunization or vaccine
A vaccine contains either
dead or live viruses or enough of the outercoat of a virus to stimulate a full immune response and to impart lifelong immunity
ABO blood types
ABO antibodies circulate in the plasma of the blood and bind w/ ABO antigens in the event of an improper transfusion
Certain danger from a transfusion comes when
the recipient has antibodies to the donor’s antigens
Cross-match
before someone receives a transfusion of blood, samples of the recipient’s and the donor’s blood must be mixed in the lab to determine and ensure compatibility
Why is blood type O known as the universal donor?
because it has no blood cell antigens to be clumped by the recipient’s blood
Blood type AB is known as the universal recipient because
there are no antibodies to clump the donor’s blood
4 types of human blood types:
Blood types are inherited, and your blood type
A, B, O, AB
doesn’t change during your lifetime
Blood type: A
Antigens present on the surface of the RBCs:
Antibodies present circulating in the plasma:
A
B (antibodies against B)
Blood type: B
Antigens present on the surface of the RBCs:
Antibodies present circulating in the plasma:
B
A (antibodies against A)
Blood type: O
Antigens present on the surface of the RBCs:
Antibodies present circulating in the plasma:
none
A and B (antibodies against A and B)
Blood type: AB
Antigens present on the surface of the RBCs:
Antibodies present circulating in the plasma:
A and B
no antibodies against A or B
AIDS
acquired immune deficiency syndrome
-people with AIDS are highly susceptible to opportunistic diseases, infections, and cancers that take advantage of a collapsed immune system
The virus that causes AIDS, HIV (human immunodeficiency disease) mainly attacks
helper T cells
The virus that causes AIDS, HIV (human immunodeficiency disease) mainly attacks
helper T cells
HIV is a retrovirus. Once inside a cell, it
transcribes itself in reverse, that means that the viral RNA uses the enzyme reverse transcriptase to make DNA
-the opposite of the typical DNA transcribing mRNA, the host cell then integrates this newly formed DNA into its own genome
What are allergies?
hypersensitive immune responses to certain substances called allergens
-involve the release of excessive amounts of histamine, an anti-inflammatory agent , which causes blood vessels to dilate
What does a normal allergic reaction involve?
What can counteract these symptoms?
redness, runny nose, and itchy eyes
-take antihistamines
Sometimes, an acute allergic response can result in a life-threatening response called
anaphylactic shock that can result in death within minutes
Antibiotics
medicines that kill bacteria or fungi
While vaccines are given to prevent illness caused by viruses, antibiotics are administered
after a person is sick. They cure the disease
Vaccines
prevent viral infections
-there is no cure for viral infections as there is for bacterial infections.
Vaccine against HPV (human papilloma virus, causes cervical cancer)
- first vaccine designed to prevent cancer
- recommended for girls between the ages of 11 and 12
Autoimmune disease
caused by a mistake of the immune system
-the system can’t distinguish between self and nonself and instead perceive certain structures in the body as foreign and produces antibodies to attack them
Examples of autoimmune disease
multiple sclerosis, lupus, rheumatoid arthritis, juvenile diabetes
Multiple sclerosis
Juvenile diabetes
- immune system attacks the myelin sheath surrounding certain neurons, treatment varies
- treatment is shots of insulin
In other diseases, the goal is to
reduce symptoms by suppressing the immune system while maintaining the body’s ability to fight disease
Antibiotics _______
Vaccines ________
cure
prevent
