Lecture Test 3 Part 2 Flashcards
What is the thoracic duct?
larger duct that drains lymph from the left side of the head, left chest, left upper arm, and the entire body below the diaphragm.
Where does the thoracic duct drain into?
left subclavian vein
Unlike the cardiovascular system, the lymphatic system is
pumpless
What helps lymph flow in lymphatic vessels?
valves
milking by skeletal muscles
breathing
How does lymph flow differ from blood flow?
lymph flow is slower and spoadic
How much lymph enters the lymphatic vessels per day?
3L
What is the effect of blocking the drainage of interstitial fluid in the lymphatic system?
lymphedema (swelling)
What is lymphoid tissue?
houses lymphocytes
What type of tissue is lymphoid tissue?
reticular connective tissue made of reticular fibers
what are reticular fibers?
very fine collagen fibers
What are lymphoid organs?
red bone marrow nodes spleen thymus tonsils
what are the smaller lymphoid structures?
appendix
peyer’s patch
what is red bone marrow?
responsible for production of lymphocytes and macrophages
where is red bone marrow found?
inside SOME bones
what occurs in red bone marrow?
hemapoiesis
what is the lymph node?
encapsulated oval structures located alond lymphatic vessels
Where can large congregations of lymph nodes be found?
inguinal, cervical and axillary regions
What are the 2 major functions of lymph nodes?
filtration
activating the immune system
How do the lymph nodes filter lymph?
macrophages and lymphocytes destroy microorganisms that enter from the lymph and prevent them from entering blood and spreading to the rest of the body.
What are the lymph nodes role in activating the immune system?
they contain germination centers for lymphocytes and monocytes
Lymph nodes are the only organ that
filters lymph
what is a lymphadenopathy?
enlargement of the lymph nodes with no pain. Usually implies cancer
What is a lymphadenitis?
enlargement of the lymph nodes with pain usually due to infection
What is the anatomy of the spleen?
size of a fist
soft and rich in blood
under the diaphragm, on the left side
The spleen provides a site for
immune functions
blood production in the fetus
what is the spleen’s main function?
to remove old and dying RBCs and be a blood reservoir
The spleen’s capsule is
thin and can easily rupture due to trauma
When a spleen’s capsule ruptures….
the spleen must quickly be removed and the splenic artery must be tied off to prevent hemorrhaging
What is the removal of the spleen called?
spleenectomy
After a spleenectomy has occurred, who takes over the function of the spleen?
liver and red bone marrow
what is the location of the thymus?
anterior and superior to the heart
what hormone does the thymus secrete?
thymosin
what is the function of thymosin?
matures t cells
How big is the thymus?
increases in size until the first birthday then stays the same size until age 60
What happens to the thymus at age 60?
it becomes smaller and much of its functional tissue is replaced by fibrous connective tissue
what are the tonsils?
MALT
what is MALT?
mucosa associated lymphatic tissue
what are the three groups of tonsils?
palatine tonsils
lingual tonsils
pharangeal tonsils
what are palatine tonsils?
largest of the tonsils and most easily infected
where are the palatine tonsils located?
either side of the posterior cavity
what happens to palatine tonsils in adults?
they decrease in size
what are lingual tonsils?
found at the base of the tongue
what are pharyngeal tonsils?
posterior wall of the nasopharynx
pharyngeal tonsils are also called
adenoids
what is the peyers patch?
clusters of lymphoid tissue containing lymphoid cells that offer immune protection to the ileum
what is the appendix?
tubular offshoot of the cecum composed of lymphatic tissue and cells
what is Hodgkin’s disease?
form of cancer that arises in the lymph nodes
what are the symptoms of Hodgkin’s?
painless swelling of the lymph nodes (usually in the neck) night sweats fever fatigue weight loss
what is the treatment for Hodgkin’s?
radiation
chemotherapy
bone marrow transplants
Hodgkin’s disease is considered
curable
What are the two defense systems?
innate immunity (nonspecific defense) adaptive immunity (specific defense)
what is innate immunity (nonspecific)?
group of protective mechanisms that respond immediately to protect the body from ALL foreign invaders.
What is adaptive immunity (specific)?
group of protective mechanisms that mounts its attack against a specific invader.
The cells that attack during an adaptive immunity attack are
are specific for that foreign substance and have memory
Innate and adaptive immunity occur
at the same time and work together to protect the body
what are pathogens?
harmful or disease causing organisms
what are the seven tools of the innate immunity system?
species resistance mechanical barriers chemical mediators natural killer cells phagocytes inflammation fever
what is species resistance?
a given species is susceptible to diseases that may be unique to that species and to no other.
what types of infections can cross species?
zoonotic infection
what is a type of zoonotic infection?
rabies
what are mechanical barriers?
the body’s first line of defense
what are some examples of mechanical barriers?
skin that is unbroken
tears
saliva
Mucous membranes are a type of mechanical barrier because
they secrete substances that can kill invaders
what is a lysozyme?
an enzyme that destroys bacteria
what is an example of a lysozyme?
tears
saliva
HCL
what are two types of chemical mediators?
interferon
complement
what is interferon?
substance produced by cells toxic to viruses
interferon is
nonspecific so it protects against a number of viruses
How does interferon work?
protects neighboring cells
what is complement?
group of at least 20 plasma proteins that normally circulate in the blood in an inactive state. When stimulated they complement the functioning of innate and adaptive immune systems
what are some examples of complement?
membrane attack complex
chemotaxic agents
histamines
opsonization
what is membrane attack complex?
punches holes in cell walls
what are chemotaxic agents?
attract WBCs to the area
How are histamines a complement activity?
complement stimulates the release of histamines from basophils and platelets as a result of trauma. This increases the permeability of blood vessels in the injured area
what is opsonization?
improving phagocytes ability to adhere to the pathogen
what are natural killer cells?
unique white blood cells that “police” the body in the blood and the lymph
natural killer cells have the ability to
find and lyse some cancer and virus affected cells before the immune system is activated
How do natural killer cells work?
not by phagocytosis but by attaching themselves to their target and destroying its cell membrane
what do natural killer cells secrete?
perforins
what are phagocytes?
cells that eat organisms
what are the chief phagocytes?
macrophages
where do macrophages derive from?
circulating monocytes that leave the blood stream and enter through the tissues and enlarge
what are wondering macrophages?
macrophages that constantly wander through the interstitial spaces looking for invaders
what are fixed macrophages?
macrophages that remain within certain organs
what is an example of a fixed macrophage?
kupffer cells in the liver
what is another type of phagocyte?
neutrophils
eosinophils are
slightly phagocytic
what sometimes prevents phagocytes from being successful?
inability to adhere to the invader
how is inflammation a part of innate immunity?
prevents the spread of damaging agents
disposes of debris and pathogens
sets the stage for repair
what are the four signs of inflammation?
redness heat swelling pain (sometimes a loss of function in serious injury)
_________ leads to a release of various chemicals
tissue injury
the release of certain chemicals after inflammation causes
dilation of blood vessels increase permability of blood vessels swelling pain chemotaxis of WBCs
the dilation of blood vessels causes
more blood to go to the area of the injury causing redness and heat
increased permeability of the capillaries causes
emigration
swelling is
increased amount of blood in the vessels leads to an increase in pressure within the capillaries resulting in more fluid escaping into the interstitial spaces
pain is caused when
swelling puts an increase of pressure on the nerves
chemotaxis of WBCs is due to
leukocytosis
what is leukocytosis?
injured cells stimulate rapid release of neutrophils
Within one hour after inflammation, neutrophils
have collected at the site of injury and are eating the invader
Following neutrophils, ________ are second responders
monocytes
monocytes swell and
increase the number of lysosomesin the cytoplasm to become macrophages.
Macrophages are responsible for
the final clean up of the infected area and the dead neutrophils
What happens to severe infections?
pus accumulates
what is pus?
a mixture of dead neutrophils, broken down tissue cells, pathogens and macrophages
What is an absess?
When pus accumulates under the skin.
Fever is a
systemic protective mechanism against a pathogen
Body temperature is regulated by
the hypothalamus
Normal body temperature is
99.7 degrees
What are pyrogens?
a secretion of lymphocytes, neutrophils and macrophages as they attack pathogens
Pyrogens stimulate the release of
prostaglandins which raises the set thermostat
When a person has chills during a fever it indicates
that the fever is rising.
Why do you have chills during a fever?
the muscles are contracting to produce more heat in order to reach the new temperature setting in the hypothalamus.
When a person sweats during a fever
it indicates that the fever is dropping
Mild fevers are beneficial because
there is an increase in metabolic rate of tissue cells speeding up defensive actions and repair processes
High fevers can be dangerous because
they can inactivate enzymes leading to tissue damage and death
How does aspirin work?
prevents temperature from rising.
Aspirin is an
antiprostaglandin that makes you feel better
What are antigens?
substances that stimulate an adaptive immunity
Antigens can be classified as
foreign antigens or self antigens
What are foreign antigens?
antigens not produced by the body but introduced from the outside
What are some examples of foreign antigens?
bacteria
viruses
parasites
transplanted tissue
what are self antigens?
molecules produced by the body that stimulate an adaptive immune response
What are some examples of self antigens?
autoimmune diseases
Adaptive immunity results from the activities of
T cells and B cells ( a type of lymphocyte)
T cells and B cells have been programmed at birth to
respond to specific antigens
In a lifetime, T and B cells
will never be challenged
In order for an adaptive immunity response to occur
lymphocytes must recognize the specific antigen and after recognition, the lymphocytes must increase in number to effectively destroy the antigen
As T and B cells are produced, they develop
receptors that are programmed to recognize different epitopes that they may come in contact with during the person’s life time
What is an epitope?
specific regions of a given antigen that will be recognized by specific populations of T and B cells
Some antigens bind to
their receptors and directly activate B and T cells
Most lymphocyte recognition involves
major histocompatibility complexes
what are major histocompatibility complexes?
glycoproteins that are unique to an individual (except identical twins) that are found on all cell membranes except red blood cells
Once recognition occurs, the specific lymphocyte
goes through cell division increasing the number of cells equipped to destroy the antigen.
Where does cell division occur?
lymphatic tissue
Many times ____________ are necessary in recognition between antigen and its specific cells.
antigen presenting cells
What is an example of an antigen presenting cell?
macrophages
How do macrophages function?
They first phagocytize the antigen. The partially digested antigen is then displayed on the surface of the macrophage and then presented to the T and B cells for recognition.
Recognition between the specific antigen and its T and B lymphocytes also needs ____________ with cytokines and other cells called helper T cells
costimulation
what are helper T cells?
cells that proliferate first when meeting an antigen through the secretion of interleukin 2. The specific T/B cells increase and will directly be responsible for destroying the antigen by proliferation of these specific lymphocytes into identical cells called a clone
what is a clone?
a population of identical cells
T cells develop from
hemocytoblasts in the red bone marrow
T cells then migrate to the ________ to mature
thymus gland
In the thymus T cells develop
immunocompetence
Immunocompetence:
the ability to carry out immune responses if properly stimulated
Most T cells arise before
puberty but some continue to develop throughout its life
T cells develop ________ on the cell membrane that can recognize specific antigens that the body may be challenged with in life
antigen receptors
T cells are very effective against
fungi parasites viruses cancer cells foreign tissue transplants
Mature T cells will leave the thymus gland and
become embedded in lymphoid tissue or will freely circulate
What are the different subpopulations of T cells that are vital in response
helper T cells
Cytotoxic T cells
Memory T cells
suppressor t cells
what are helper t cells?
cells that do not directly attack the antigen but produce cytokines mainly interleukin 2
what are cytokines
small hormones that are involved with cell functions
interleukin 2 is needed for
all adaptive immune responses.
Without helper t cells
the adaptive immune system is nonfunctional
what are cytotoxic t cells
cells that are directly responsible for destroying the invader always requiring costimulation by helper T cells.
After being activated and proliferating in the lymphoid tissues, cytotoxic t cells
migrate to the site of invasion and produce perforins and lymphotoxins that will destroy the specific invader
what are memory t cells?
cells that are programmed to destroy a recurring invader (chicken pox)
The secondary reaction of memory t cells will be
much faster and the person may not ever know that they’ve come in contact with the antigen again.
What are suppressor t cells?
poorly understood, probably associated with tolerance/autoimmune disease
When B cells are activated they will produce
antibodies that kill the specific antigen
B cells are formed from
hemocytoblasts in red bone marrow
b cells mature in
red bone marrow and gain immunocomptency
After b cells gain immunocompetency,
they leave the RBM and establish residency within a lymphoid tissue or circulate
After recognition of specific antigens occurs
proliferation follows
During proliferation
B cells enlarge, divide and differentiate into plasma cells
Plasma cells produce
antibodies
The B cells that don’t become plasma cells
form memory cells
Plasma cells produce
2,000 molecules of antibodies per second for 4-5 days
What is an antibody?
protein produced in response to an antigen
The antibodies produced by the clone of plasma cells
enter circulation and form Antigen-antibody complexes with the specific antigen.
What are the different ways an antibodies destroy antigens?
immobilization
agglutination and precipitation of antigen
activation of complement
initiation of inflammatory response
What is immobilization:
antibodies form against the cilia or flagella of some bacteria and these bacteria lose their mobility
what is agglutination and precipitation of antigen?
the antibodies may cause the antigens to clump together. Phagocytosis is easier
What is activation of complement?
antigen-antibody complexes initiate complement activation
What are the 5 different classes of antibodies that plasma cells produce?
IgG IgA IgM IgD IgE
IgG is
most abundant 80% of all antibodies in the body
IgA:
15% of antibodies
IgM:
5-10% of antibodies
IgD:
Less than 1% of antibodies
IgE:
less than 1% of antibodies. Involved with allergic reactions
What are B memory cells?
cells that quickly recognize the antigen during a later exposure and kill it before the body reacts to it.
The secondary respose of B cells:
is much quicker and stronger than the primary response
What is lag time?
time between the invasion of antigen into body and the appearance of antibodies
Why is there a lag time?
due to the time needed for the specific B cells to divide and differentiate into plasma cells
what are autoimmune diseases?
the immune system fails to recognize itself and lanches an immune attack against its own system
What are some examples of autoimmune disease?
rheumatoid arthritis, diabetes mellitus, multiple sclerosis and lupus
What causes autoimmune inflammatory disease of connective tissue?
unknown but occurs in families
who is mostly affected by autoimmune disease of connective tissue?
women
what are the symptoms of autoimmune disease of connective tissue?
pain in joints
photosensitivity
rash across the eyes and nose
inflammation of kidneys, liver, spleen, heart and central nervous system
what is an allergic reaction?
an over reaction to an antigen that is tolerated by most others
the antigen that causes an allergic reaction is called an
allergen
what are some common allergens?
milk nuts some drugs vaccines some plants venoms
what is the outcome of allergic reactions?
varies from a congested nose to anaphylaxis
what is anaphylaxis?
severe reaction with an allergen that results in mass vasodilation, increased permeability (leading to swelling), increased smooth muscle contraction the airways of the lungs and increased mucus production
what is tissue rejection?
When the body recognizes transplant tissues as nonself and mounts an immune response.
The more similar the surface proteins are between donor and recipient,
the weaker the rejection response.
What is the drug used in transplants to decrease tissue rejection?
cyclosporine
What is cancer?
when a normal cell transfers into a cancer cell it displays tumor antigens.
If the immune system can detect cancer cells as nonself,
they can be destroyed.
What is immunological surveillance?
there are cells that are constantly circulating and guarding against the appearance of cancer cells.
What happens to immunological surveillance as we age?
it decreases and cancer risk increases.
What is AIDS?
an immunological disease identified in the 1980s cause by human immunodeficiency virus
How was AIDS first identified?
CDC in Atlanta had high rates of pneumocytosis pnemonia
what causes pnemocytosis pneumonia?
a protozoan and a Kaposi’s sarcoma.
What is a Karposi’s sarcoma?
cancer of the blood vessels seen as purple lesions on the skin
Who is mostly affected by Karposi’s sarcoma?
elderly homosexual men
HIV cannot
live long outside its host
HIV is transmitted by
body secretions such as blood, semen, vaginal secretions, tears and saliva
What types of cells can HIV enter?
helper t cells
macrophages
brain cells
When helper T cells are invaded by HIV
the population is decreased and the immune system colapses
How do patients usually die from AIDS?
opportunistic diseases such as cancer, pneumonia, or a raging infection
When do symptoms of HIV occur
a few months to ten years after diagnosis
What are nonprogresssors?
people who have been infected by HIV but after 10-15 years show no symptoms of it
HIV is a
retrovirus
what is a retrovirus?>
its genetic code is found on RNA not DNA
The core of HIV contains
RNA and reverse transciptase
What surrounds the core of a HIV cell?
protein coat or capsid
The enter HIV cell is surrounded by
a lipid bilayer with glycoproteins
what is the function of the glycoproteins
help the HIV to bind and enter target cells
How does the virus enter the host cell?
reverse transcriptase produces viral DNA from RNA. THe DNA inserts itself into the hosts DNA and directs it to produce new viruses.
HIV has a high
mutation rate changing its coat rapidly and making the development of a vaccine hard
What is the treatment for HIV/AIDS?
combination therapy of AZT and protease
What does AZT do?
it is a reverse transciptinase inhibitor
what does protease do?
prohibits the manufacturing of the protein coat on new viruses
