lymphatic system and immunity Flashcards
what does the lymphatic system do
transports excess fluid away from the interstitial spaces and returns it to the bloodstream.
are lymphatic capillaries open or closed?
Closed-ended tubes that extend into the interstitial spaces to form complex networks that are associated with blood capillaries
What type of cells do lymphatic capillaries consist of
single layer of squamous epithelial cells
what are lymphatic vessels
formed by merging of lymphatic capillaries
composed of 3 layers: epithelial lining, middle layer of smooth muscle and elastic fibers, out layer of connective tissue
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what are lymph nodes
masses of lymphoid tissue
what do the lymphatic trunks do
drain lymph from large regions of the body
“typically named after the area it is located in”
what are the two ducts known as
Thoracic duct and right lymphatic duct
what region is the thoracic duct responsible for
begins in abdomen as CISTERNA CHYLI passes upward through the diaphragm beside the aortas and empties into the left subclavian vein; drains lymph from LOWER BODY REGION, left arm and left side of head and neck
what region is the right lymphatic duct responsible for
originates in the right thorax and empties into the right subclavian vein; drains lymph from right side of head neck and right arm and right thorax
which collecting duct is larger
thoracic duct
what does lymph do
returns proteins to blood that leaked into interstitial space and transports foreign particles to lymph nodes
movement of lymph is controlled mostly by what
muscular activity and valves
metastasis
spread of cancer from one area of the body to another
what are the primary lymphatic organs
red bone marrow (located in flat bones and the epiphyses of long bones) and the thymus glad which produce T and B cells
what are the secondary lymphatic organs
lymph nodes, spleen, and lymphatic nodules
where do most immune responses occur
secondary lymphatic organs
does the thymus gland have efferent and afferent supply?
No it does not have afferent lymphatic supply
how does blood enter the thymus gland
by branches of subclavian artery and enters at the medulla
what is thymosin
a hormone which promotes proliferation and maturation of T-cells
where is the thymus gland located
in the mediastinum in front of the aortic arch and behind the sternum
where are afferent vessels located on lymph nodes
enter on convex surface
where are efferent vessels located on lymph nodes
exit from the hilum
what is the capsule of the lymph node
white fibrous connective tissue extends into the node dividing it into compartments which contain lymphocytes and macrophages known as NODULES
what are lymph sinuses
spaces within the node which provide complex network of chambers and channels which lymph circulate through as it passes through the node
where is the spleen located
in the upper left portion of the abdominal cavity just beneath the stomach
what is the spleen filled with
blood
the tissues of the spleen are known as what
pulp (red and white)
what does red pulp contain
red blood cells, lymphocytes, and cellular debris
fills remaining space
what does white pulp contain
contains lymphocytes and distributed in tiny islands
infection
condition caused by the presence and multiplication of a pathogen
pathogen
disease producing agents which include viruses, bacteria, fungi, parasitic forms of life
immunity
bariety of defense mechanisms in the body that prevent the entrance of pathogens or destroy them if they enter the tissues; two major types of immunity (specific and nonspecific)
what does it mean to be species resistant
a species or organism is resistant to certain diseases that other species are susceptible to
what are mechanical barriers
unbroken skin and mucous membranes help prevent the entrance of some infectious agents