the lyphatic sys is made up of
lymph vessels structures and organs that cont. lymphatic tissues and red bone marrow
functions of lyphocytes
drain interstitial fluid transport dietary lipids and protects with immune responses
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
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
how does lymph flow
due to the "milking action" action of skeletal muscle contraction and pressure changes that occur during inhalation
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
primary lymphatic organs and tissues are the sites where stem cells divide and develp what
mature B and T cells
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
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
when many bacterial toxins elevate body temp by triggering release of fever causing substances
adaptive immunity involves in the production of what
spefic types of cells or antibodies to destroy a particular antigen
mature T cells develope where
in the thymus from where immature t cells that migrated from the bone marrow
cell mediated immunity
is effective against fungi, parasite, intracellular viral infections, cancer cells, and foreign tiss. transplants
what is the function of (APCs)
the process the antigen to activate t cells and secrete substance to dvide t cells and b cells
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.
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 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 is the Right Lymphatic Duct?
Drains the right upper arm and the right side of the head and thorax.
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 is an Antigen?
Anything the body perceieves as foreign. Bacteria and their toxins, viruses, mismatched RBC's, cancer 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 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 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 are the Tonsils?
Simplest lymhoid organs; form a ring of lymphatic tissue around the pharynx.