Lymphatics Flashcards
What contains lymphatic tissue?
Thymus, spleen & lymph nodes
Functions of the lymphatic system (x3)
Drains excess interstitial fluid from tissue spaces & returns it to the blood
Transportation of dietary lipids & lipid soluble vitamins from the GI tract (ADEK)
Carry out immune responses (kill abnormal cells + secrete antibodies)
Characteristics of lymphatic capillaries
One way vessel
Has a single layer of endothelial cells (there are openings between these cells)
Endothelial cells are connected to the surrounding tissue by anchoring filaments
What happens to the anchoring filaments when there is an excess of interstitial fluid?
The anchoring filaments are pulled –> openings between endothelial cells get bigger (fluid will move into lymphatic capillaries, pressure gradient)
What aids the flow of lymph? (x3)
Valves: prevents back flow (one way movement)
Skeletal muscle pump: muscles milk lymph vessels (forces lymph to the internal jugular + subclavian veins)
Respiratory pump: inhalation = increased return (pressure changes allows lymph to go from abdomen –> thoracic region)
2 areas for drainage of lymph
Thoracic duct
Right lymphatic duct
What does the thoracic duct drain?
Everything but upper right limb
What does the right lymphatic duct drain?
The upper right limb only
Primary lymphoid organs
Immune cell production + immune cell education
Examples: red marrow & thymus
Secondary lymphoid organs
Where most of the immune response occur
Examples: lymph nodes/nodules & spleen
Lacks capsule covering –> not an organ
What are MALT?
Mucosa associated lymphatic tissue: spread throughout mucous membranes lined the GI, urinary + repro tracts & respiratory airways
Purpose of lymph nodes
Acts as a filter
More incoming vessels than outgoing (slows lymph from leaving the lymph node, allows for more filtration time)
What is the germinal center?
Where lymphatic cells can develop
Spleen: lymphatics
Largest single mass of lymphatic tissue
Composed of red & white pulp
Red vs white pulp
Red pulp: acts like red bone marrow in the fetus - produces RBCs
White pulp: contains lymphocytes
