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BIO 211 (UNIT # 2) CH 20 The Lymphatic System

Mr Daigle Bio 211 (A&P 2) CCTC Spring 2011
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lymphatic system
body sys. responsible for adaptive immunity
the lyphatic sys is made up of
lymph vessels structures and organs that cont. lymphatic tissues and red bone marrow
it is lymph
when interstitial fluid passes into lymphatic vessels
lymph and interstitial fluid relation
chemically similar to blood plasma
interstitial fluid
components of blood plasma filter through blood capillary walls to form this
lymphocyte
is a type of WBC in the vertebrae immune system
functions of lyphocytes
drain interstitial fluid transport dietary lipids and protects with immune responses
depth of immune responses
protects the body against invasion
depth of trasportation of dietary lipids
transports lipids and lipids soluble vitamins from the g.i tract to the blood
depth in draining of interstitial fluid
lymphatic sys drains tissue spaces of excess fluid and returns proteins that have escaped from blood to the cardiovascular system
lymphatic vessels begin as what
lymphatic capillaries
lymphatic capillaries merge to form larger
lymphatic vessels
where does the lymphatic vessels drain
the thoracic duct (main) or right lymphatic duct
what are located in intervals along lyphatic vessels
lymph nodes
thoracic duct drains into
left subclavian vein
Rt. lymphatic duct drains into
Rt. subclavian vein
lymph nodes consist of
masses of b cells and t cells surronded by a capsule
lymphatic organs
thymus lymphatic nodes spleen lymph nodules and bone marrow
passage of lymph
from interstitial fluid to lymphatic capillaries to lymphatic vessels and lymph nodes to the thoracic duct to rt. subclavian vein to the junction of the internal jugular and subclavien veins
valves of the lymphatic system prevent what
backflow of lymph
how does lymph flow
due to the "milking action" action of skeletal muscle contraction and pressure changes that occur during inhalation
skeletal musc. forces lymph where
towards the subclavian veins
afferent lymphatic vess.
filtered lymph enters a node through this
efferent lymphatic vess.
filtered lymph leaves the other end of the node through one or two of this
two lobed organ located posterior to ths sternum and medial to the lungs and superior to the heart
thymus
largest single mass of lymphatic tissue in the body
spleen
spleen is made from
capsule of dense conn. tiss.
stem cells in red bone marrow give rise to
mature B cells and immature T cells
mature B cells and immature T cell migrate where
to the thymus
primary lymphatic organs and tissues are the sites where stem cells divide and develp what
mature B and T cells
what organs are included when B andT cells are mature
red bone marrow and the thymus
sites where most immune responses occur
secondary lymphatic organs and tiss.
the immune responses occur in what organs
lymph nodes spleen and and lmphatic nodules
lymphatic nodules description
oval shaped concentrations of lymphatic tiss. that are not surronded by a capsule
in what organs are the lymphatice nodules scattered in
the gi respiratory urinary and reproductive tracts
tonsils function
to participate in immune responses agains inhaled or ingested foreign substances
names of tonsils
pharyngeal palatine and ligual
pharyngeal tonsil
embedded in the posterior wall of the upper part of the throat
palatine tonsil
lie at the back of the throat on either side (commonly removed in tonsillectomy)
lingual tonsil
located at the base of the tongue can be removed during tonsellectomy
innate immune defenses include (outer)
barriers provided by the skin and mucous membranes (first line of defens)
innate immune defenses include (inner)
internal antimicrobial proteins, phagocytes and natural killer cells, inflammation and fever
inflammatory response
is the defensive response to tissue damage
sign of infammation
redness, pain heat and swelling
fever occurs
when many bacterial toxins elevate body temp by triggering release of fever causing substances
fever causing substnces
macrophages and interleukin-1
define antingen
any subsance that the adaptive immune system recognizes as foreign
adaptive immunity involves in the production of what
spefic types of cells or antibodies to destroy a particular antigen
B cells complete their development where
in red bone marrow
mature T cells develope where
in the thymus from where immature t cells that migrated from the bone marrow
responsible for cellular immunity
T cells
sub population for T cells
cytotoxic T cells, helper T cells and memory T cells
cell mediated immunity
is effective against fungi, parasite, intracellular viral infections, cancer cells, and foreign tiss. transplants
(APCs)
antigen presenting cells
what is the function of (APCs)
the process the antigen to activate t cells and secrete substance to dvide t cells and b cells
anti body mediated immunity is most effective against what
viral and bacterial infections
antibody mediated immunity is produced by
descendants of b cells called plasma cells
destruction of antigens by antibodies
is referring to antibody mediated immunity
What are Lymph vessels?
One way system, lymph flows toward the heart.
What do Lymph vessels (lymphatics) include?
Lymphatic capillaries, lymphatic collecting vessels, lymphatic trunks and ducts.
What are Lymphatic Capillaries?
Similar to blood capillaries, with modifications: Very permeable, loosely joined endothelial minivalves.
Where are Lymphatic Capillaries absent?
Bones, teeth, bone marrow and the CNS.
What are Minivalves?
Function as one way gates that allow interstitial fluid to enter lymph capillaries, do not allow lymph to escape from the capillaries.
What do Lymph Capillaries absorb during inflammation?
Cell debris, pathogens, cancer cells.
What do the cells in the lymph nodes do?
Cleanse and examine.
What are Lacteals?
Specialized lymph capillaries present in intestinal mucosa. Absorb digested fat and deliver fatty lymph (chyle) to the blood.
What are Lymphatic Collecting Vessels?
Have the same three tunics as veins, have thinner walls, with more internal valves, anastomose more frequently.
What are Lymphatic Trunks?
Formed by the union of the largest collecting ducts.
What is the Right Lymphatic Duct?
Drains the right upper arm and the right side of the head and thorax.
What is the Thoracic Duct?
Arises from the cisterna chyli and drains the rest of the body.
Where do both Lymphatic ducts empty lymph into?
Venous circulation at the junction of the internal jugular and subclavian veins on its own side of the body.
What are the Lymphoid Cells?
Lymphocytes.
What are the two main varieties of Lymphocytes?
T Cells (T lymphocytes), B Cells (B lymphocytes).
What do T cells and B cells do?
Protect the body against antigens.
What is an Antigen?
Anything the body perceieves as foreign. Bacteria and their toxins, viruses, mismatched RBC's, cancer cells.
What do T cells do?
Manage the immune response, attack and destroy foreign cells.
What do B cells do?
Produce plasma cells, which secrete antibodies. Antibodies imonbilize antigens.
What are Lymph Nodes?
Principal lymphoid organs of the body. Embedded in connective tissue and clustered along lymphatic vessels.
Where do Aggregations of Lymph nodes occur?
Near the body surface in inguinal, axillary, and cervical regions of the body.
What are the two basic functions of Lymph nodes?
Filtration and immune system activation.
What is Filtration?
Macrophages destroy microorganisms and debris.
What is Immune System Activation?
Monitor for antigens and mount an attack against them.
What is the structure of a Lymph Node?
Bean shaped and surrounded by a fibrous capsule.
What are the distinct histologically regions of Lymph Nodes?
Cortex and a medulla.
What is the circulation in the Lymph Nodes?
Only lymph nodes filter lymph. Lymph enters via afferent lymphatic vessels. It meanders through these sinuses and exits the node at the hilus via efferent vessels. Because there are fewer efferent vessels, lymph stagnates somewhat in the node. This allows lymphocytes and macrophages time to carry out protective functions.
What is the Spleen?
Largest lymphoid organ, located on the left side of the abdominal cavity beneath the diaphragm. It is served by the splenic artery and vein, which enter and exit at the hilus.
What are the functions of the Spleen?
Site of lymphocyte proliferation, immune surveillance and response, cleanses the blood. Stores breakdown products of RBC's for later reuse. Stores blood platelets. Site of fetal erythrocyte production.
What is the Structure of the Spleen?
Two distinct areas, white pulp and red pulp.
What is the White Pulp of the Spleen?
Containing mostly lymphocytes suspended on reticular fibers and involved in immune functions.
What is the Red Pulp of the Spleen?
Remaining splenic tissue concerned with disposing of worn out RBC's and bloodborne pathogens.
What is the Thymus?
A Bilobed organ that secretes hormones (thymosin and thymopoietin) that cause T lymphocytes to become immunocompetent.
How does the size of the Thymus vary with age?
In infants it is found in the inferior neck and extends into the mediastinum where it partially overlies the heart. It increases in size and is most active during childhood. It stops growing during adolescence and then gradually atrophies.
How does the Thymus differ from other lymhoid organs?
It functions strictly in T lymphocyte maturation, it does not directly fight antigens.
What do the hormones of the Thymus do?
Stimulate lymphocytes to become immunocompetent.
What are the Tonsils?
Simplest lymhoid organs; form a ring of lymphatic tissue around the pharynx.
What are Palatine Tonsils?
Either side of the posterior end of the oral cavity.
What are the Lingual Tonsils?
Lie at the base of the tongue.
What are the Pharyngeal Tonsils?
(Adenoids) - posterior wall of nasopharynx.
What are the Tubal Tonsils?
Surround the openings of the auditory tubes into the pharynx.

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