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