Lymphatics Flashcards
What is lymph made up of
Fluid and plasma proteins only
It can gain lymphocytes as it flows through the lymphatic capillaries and channels (e.g. fats will be added in the small intestine)
What does the flow in the lymphatic system rely upon
Muscle contraction
Pressure changes
Gravity
What is the flow in the lymphatic system similar to
Veins
Why is the flow in the lymphatic system unidirectional
Due to valves
What happens to the fluid flow into extracellular spaces an infection
Increases due to protein accumulation (osmosis) which drives an increased lymph flow and therefore the immune response in the nodes, as more antigens are being presented and phagocytosis occurs
What are the 4 main functions of the lymphatic system
Tissue drainage
Return of plasma and plasma proteins
Absorb fat from the gut
Immunity
How can the lymphatic system drain tissue and return plasma proteins
Drains must escape cell-free plasma (tissue fluid) from the extracellular spaces back to the venous system (about 8L a day)
What does a lymph node consist of
Mass of lymphatic tissue that is surrounded by a fibrous capsule
Every node is connected to an incoming and outgoing lymph vessel
What are germinal centres
Secondary lymphoid follicles
What are lymph nodes
Secondary lymphoid tissues of about 0.1-2.5cm in diameter where the immunological (acquired immunity) functions of the lymph are located
Lymph nodes can be
Isolated
Grouped
Where are grouped lymph nodes found
At the bases of major arterial trunks
How much lymph is approximately produced per day
8L
What happens to the lymph produced everyday
About half is reabsorbed into the lymph nodes
How many lymph nodes are there in a young adult
About 450
How many lymph nodes in the abdomen are chiefly associated with the mesenteries
250
What are the lymph nodes in the abdomen chiefly associated with the mesenteries known as
Deep lymph nodes
Give an example of superficial lymph nodes
Inguinal nodes located in and around the femoral triangle at the base of the lower limb
Give an example of a primary lymphatic tumour
Hodgkins
How does a secondary tumour form
As a result of metastasis from other sites
How does lymphatic fluid drainage occur
Initially it occurs symmetrically from the limbs, head, neck and trunk
Deep lymphatic drainage will normally follow the routes of arterial supply
Eventually all the lymph congregates into 2 large lymph ducts which empty into the venous system at the jugular/subclavian junction
How many lymphatic ducts are there
Name them
2
Right lymphatic duct
Thoracic duct
What happens to the fat absorbed into the lymph from the small intestine
They drain to the SVC and eventually to the liver for absorption
Where can lymphocytes be generated and mature
Thymus and Bone marrow (1) Spleen (2) Lymph nodes (2) Peyer’s patches (2) Tonsils Lymphocytes
What is the spleen
Largest lymphatic organ
It’s present in the upper left quadrant of abdomen (peritonised)
Contains large amount of blood, routinely discharged via smooth muscle action
What occurs in the white pulp of of the spleen
The immune function where T (PALS) and B (germinal centres) cells are found
What is found in the spleen
Red pulp
White pulp
Where does lymph drainage NOT occur from
Epithelium Cartilage Bone Central nervous system Or from the majority of the spleen and liver
