17 Cells And Tissues Of Lymphatic System Flashcards
What are the levels of organisation in the lymphatic system?
Lymph
Lymphatic vessels
Lymphoid tissues and organs
What is chyle?
Lymph that arises in the GI tract
White cloudy substance - contains fats and dissolved lipids
What are the different lymphatic vessels in size order? (Smallest first)
Capillaries
Trunks
Ducts
Veins
How do the gaps between the endothelial cells in a lymphatic capillary open?
Oncotic/interstitial pressure causes the gaps to open
What are the anchoring filaments?
Reticulin (collagen 3)
Projections from the endothelial cells
Where are lymphatic vessels in relation to cardiovascular vessels?
Tend to lie adjacent to capillaries, arteries and veins
What happens with the lymphatic vessels in limbs?
Deep lymphatics pass through muscles where contraction aids lymph movement in trunks
Larger lymphatic vessels
Ducts and trunks
Contains smooth muscle cells in walls
In abdomen or thorax
Contraction of smooth muscle is important contributed to lymph flow
What is 3 valves together in a lymphatic vessel called?
Lymphangion
Compression by local veins and arteries propels the lymph
What are lymphatic trunks and ducts?
Equivalent to larger veins
Larger fibrocartilaginous valves
Skeletal muscle and organ movement used for flow
What is the cisterna chyli?
Large container of chyle from GI tract
Where does the lymph in the upper right quadrant of the body drain into?
Right subclavian vein or internal jugular vein
Where does the lymph from most of the body flow into?
The left subclavian vein or internal jugular vein
What are the 3 most important lymph nodes?
Neck (cervical)
Groin (inguinal)
Armpit (axillae)
Lymph nodes
Shaped like a kidney
Each node has multiple afferent lymphatic vessels entering
Single efferent lymphatic vessel leaving via concave hilum
Each lymph node has feeding artery and draining vein that also enter and leave hilum
What is the capsule of a lymph node made of?
Collagen 1 and reticulin
What do the follicles in the node contain?
Immune cells
E.g. macrophages, dendritic, B and T cells
What are follicular dendritic cells?
Located in germinal centres
Antigen antibody complexes adhere to dendritic processes
Cell can retain antigen for months
Causes proliferation of B cells
What is a difference between B and T lymphocytes?
B lymphocytes can recognise antigens
What us lymphadenopathy?
Enlarged lymph nodes
During infection, germinal centres full with lymphocytes causing swelling
Cancers can metastasise to lymph nodes
What are the lymphatic organs?
Thymus Spleen Tonsils Appendix Payer’s patches
Where is the thymus?
Superior mediastinum (middle of chest between lungs) Fully formed and functional at birth Starts to shrink after puberty by late teens, is mostly fat
What is the structure of the thymus?
Similar to lymph node but no hilum
No afferent vessel so secretes straight into bloodstream
What is the function of the thymus?
Maturation of bone marrow derived stem cells into immunocompetent T cells
‘Thymic cell education’
