Lymphatics Flashcards
What are the 4 functions of the lymphatic system?
- Tissue drainage
- Return of plasma & proteins that leak out
- Carries absorbed fat from the gut
- Immunity
Why does the lymphatic system need to drain tissues?
High pressure causes fluid to leak from the capillary bed
Some is taken back in by venules but much needs to be drained.
Why does the Lymp. System need to return plasma & proteins?
Plasma and its proteins leak out the capilaries as well but cant be reabsorbed by venules so have to be returened to the venous system via the lymph.
How is the lymphatic system involved in immunity?
Lymph goes via lymph nodes which contain many antibodies & lymphocytes.
Why can lymphatic vessels absorb proteins & large molecules that blood cant?
Lymphatic vessels have no basement membrane
Examples of lymphatic tissues
Spleen Thymus Marrow Tonsils Lymph nodes
What makes up Lymph?
The fluid & plasma proteins int he vessels
Gains lymphocytes when passing through capillaires & fat when through small intestine
What causes Lymph to flow?
Pressure, gravity and muscle contraction
How is lymph flow kept unidirectional?
Valves
How is lymph flow altered in an infected space?
- Protein accumulates in infected space
- increased fluid flow to extracellular space
- Increases lymph flow through area
- More antigens from space reach nodes & immune resposne increases.
Where are lymph nodes found?
Isolated all over the body or in groups at the base of major arterial trunks
What is a lymph node?
Secondary Lymphoid tissue
A filter for lymph
When will a lymph node swell?
When the area it drains is infected
What do lymph nodes do?
Filter pathogens out of the lymph using white cells & plasma cells.
How do lymph nodes notify the body of pathogens?
By releasing antibodies and antigen-presenting cells into the lymph
what else do lymph nodes filter out?
Inert particles
How are lymphatics arranged in limbs?
Superficial and deep lymphoid vessels are seperated by a fascia.
Superficial lymphatics follow superficail veins & ditto for deep.
How does lymph from superficial lymphatics return to the venous system?
Via the deep lymphatics.
Opening in the fascia allow the superficial to flow into the deep.
E.g. Saphenous opening at femoral triangle of lower limb.
How are lymphoid vessels arranged in cavities?
They follow deep arteries.
What lacks lymphoid drainage?
Eyeballs CNS Inner Ear Epidermis Cartilage Bone
What do superficail lymph nodes do?
Drain from the outer layers of fat/skin
e.g. superficial inguinal nodes at femoral triangle
How are deep lymph nodes split?
Into pre-aortic nodes and para-aortic nodes
What are pre-aortic nodes?
Those associated with midline and unpaired aortic branches suppling the GIT.
What are para-aortic nodes?
Those associated with paired, lateral aortic branches to the body walls and paired organs.
Where does all lymph end up?
In two large lymph ducts
How does lymph return to the venous system?
By emptying into the venous system at the jugular/subclavian junction.
Name the two lymphatic ducts?
Right lymphatic Duct
Thoracic Duct
Where does the right lymphatic duct drain?
The upper right quadrant of the trunk, right of head and right arm.
Where does the thoracic duct drain?
The left head, left arm, abdomen, lower limbs and upper left qadrant of the trunk.
What primary tumors grow in lymph nodes?
Lymphomas such as hodgkins lymphoma
How do tumors metastasise to the lymph nodes?
From pretty much everywhere as lymph flows eveyrwhere.
Nodes filter out cancer cells which stay in the node and multiply.
What other pathologies can affect lymph nodes?
Infections e.g. TB & glandular fever
Inflammatory Hyperplasia
From where to where does lymph carry fats?
From the small intestine to the liver
What lymph vessels are visible to the naked eye?
Those in the small intestine as theyre so laden with fat they get massive
How is the lymphatic system involved with lymphocytes?
IT transports them
Produces them in marrow
Matures them in thymus and lymphoid tissue.
Where the spleen?
Upper left quadrant of abdomen
What does the spleen do?
routinely discharges a large amount of blood by smooth muscle contraction.
What is the largest lymphatic organ?
Spleen
What are the 3 palpable lymph nodes?
Axillary
Cervical
Inguinal
Order the types of lymph vessles
'blind' capillaries Vessels Trunks Ducts (thoracic/right) Then onto venus blood supply.
