20.1 Lymphatic System Flashcards
Returns interstitial fluid leaked from blood vessels back to blood; Consists of three parts
1. Lymphatic vessels (lymphatics)
2. Lymph
3. Lymph nodes
Circulates 3L
Lymphatic system
Clear fluid in vessels
Lymph
Bulging filters that cleanse lymph
Principal secondary lymphoid organs of body
Most are embedded in deep connective tissue in clusters along lymphatic vessels
Also where immune cells are activated
Lymph nodes
Provide structural basis of immune system by housing phagocytic cells and lymphocytes
Ex. Spleen, thymus, tonsils, lymph nodes, lymphoid tissues
Lymphoid organs
One way system that includes lymphatic capillaries and larger lymphatic vessels
Lymphatic vessels
Blind ended vessels that weave between tissue cells and blood capillaries
Absent from bones, teeth, and bone marrow
More permeable than blood capillaries; Takes up larger molecules like proteins, debris, pathogens
Lymphatic capillaries
Offers a way for pathogens and cancer cells to travel
Make one way minivalves
Lymphatic capillaries
Specialized lymph capillaries present in intestinal mucosa
Absorb digested fat and deliver chyle to blood
Lacteals
Fatty lymph
Chyle
Larger lymphatic vessels; Have structures and tunics similar to veins, except have thinner walls with more internal valves
Where lymphatic capillaries drain
Collecting lymphatic vessels
Formed by union of largest collecting vessels, drain larger areas of body
Lymphatic trunks
Drains right upper arm and right side of head and thorax
Right lymphatic duct
Drains rest of body
Thoracic duct
Start of thoracic duct in individuals
Cisterna chyli
Condition in which lymphatic vessels appear as painful red lines under the skin
Caused by inflammation of larger lymphatic vessels that contain vaso vasora
Lymphangitis
Low pressure system; Milking action of skeletal muscle
Pressure changes in thorax during breathing
Physical activity will increase lymph flow
Lymph transport
Severe localized edema
Caused by anything that prevents normal return of lymph in blood
Ex. Tumors blocking lymphatics or removal of lymphatics during surgery
Lymphedema
Worms building up in lymphatic system
Elephantiasis
Help with immune response
Destroy infected cells
T cells
Produce plasma cells, which secrete antibodies
B cells
Phagocytize foreign substances and help activate T cells
Macrophages
Capture antigens and deliver them to lymph nodes
Help to activate T cells
Dendritic cells
Produce reticular fibers (stroma) in lymphoid organs
Reticular cells
Houses and provides proliferation sites for lymphocytes
Offers surveillance vantage points for lymphocytes and macrophages as they filter through lymph
Lymphoid tissue
Loose connective tissue where macrophages live
Reticular connective tissue
Loose arrangement of lymphoid cells and some reticular fibers
Found in every body organ
Diffuse lymphoid tissue
Side where fluid exits the lymph node
Hilum
Inflamed, swollen, tender lymph nodes that result when nodes are overwhelmed by what they are trying to destroy
Buboes
Blood rich organ about the size of a fist
Located on left side of abdominal cavity
Largest lymphoid organ
Served by splenic artery
Site of lymphocyte proliferation and immune surveillance and response
No trabeculae
Spleen
Site where immune function occurs in spleen
Contains mostly lymphocytes on reticular fibers
Found around central arteries
Appear as islands of white in sea of pulp
White pulp
Site where old RBCs and bloodborne pathogens are destroyed
Red pulp
Simplest of lymphoid organs
Form ring of lymphatic tissue around pharynx
Appears as swellings of mucosae
Gather and move pathogens from food and air
Tonsils
At posterior end of oral cavity
Largest of tonsils and most often infected
Palatine tonsils
Lumpy collection of follicles at base of tongue
Lingual tonsils
AKA adenoids
Located at posterior wall of nasopharynx
Pharyngeal tonsil
Surround openings of auditory tubes into pharynx
Tunal tonsils
Overlying epithelium invaginates in tonsils
Histology: White lines
Tonsillar crypts
Clusters of lymphoid follicles in wall of distal portion of small intestine
AKA aggregated lymphoid nodules
Structural similar to tonsils
Location aids in function
Peyer’s patches
Offshoot of first part of large intestine
Contains large number of lymphoid follicles
Appendix
Bilobed lymphatic organ found in inferior of neck
Where lymphoid T cells mature
Thymus
