Lymphatic System Flashcards
What is the function of the lymphatic system?
Recover 3 Litres of lost fluid from the blood each day, draining back into the sub-clavian veins
How is lymph fluid moved throughout the body?
Pressure changes in the thorax (inspiration/expiration)
Pulsations of adjacent arteries
Skeletal muscle movement from physical activity
(Some core lymphatic contain smooth muscle)
What is the clinical significance of enlarged lymph nodules/nodes?
Block the lumen of vessels entering/leaving the node, leading to static fluid and infection
What is the difference between lymph nodules and lymph nodes?
Lymph nodules are a type of lymph tissue with exposure to the external environment
Lymph nodes are secondary lymph organs that filters and controls the fluid that flows through them
Where are primary lymph organs found and what is their specific function?
Organs where lymphocytes are formed and matured:
Bone marrow (B-cells and T-cells formed here, only B-cells matured here)
Thymus (T-cells are matured here)
Where are secondary lymph organs found and what is their specific function?
Filters and monitors the contents of the lymphatic fluid and blood
Lymph nodes (filters lymph and activates lymphocytes and erythrocytes)
Spleen (filters erythrocytes and produces PAPCs)
Where are the cells of the lymphatic system found in the lymph nodes?
B-cells are found in the medulla of the lymph nodes
T-cells are found in the paracortex of the lymph nodes
FDC’s are found in the germinal cortex of the lymph nodules
What are the cells found in the lymphatic system?
Lymphocytes:
B-cells, T-cells, NK-cells
Supporting cells:
Macrophages and Follicular Dendritic Cells (FDC’s)
How does fluid enter the lymph node?
Outer (convex) surface:
Afferent lymphatics - bring lymph fluid
Inner (hilum) surface:
Efferent lymphatics - take lymph fluid and lymphocytes
Feeding artery - bring lymphocytes via blood
Draining vein - take blood
How do lymph nodes filter lymph fluid?
Lymph fluid enters via afferent lymphatics with antigens
Antigens are trapped by FDC’S and presented to B-cells and T-cells, producing an immune response
What is lymphocytosis?
What is lymphadenopathy?
Infections lead to clonal expansion of B-cells in germinal cortex’s (lymphocytosis) and swelling of the lymph node (lymphadenopathy)
What are the haemopoetic functions of the spleen?
Removal of old/damaged erythrocytes and platelets
Retrieval of Iron from Haemoglobin
What are the immune functions of the spleen?
Activation and proliferation of lymphocytes and antibodies
Antigen presentation by PAPC’s
What does systemic infection do to the spleen?
Cause swelling
Swelling can cause a ruptured spleen leading to exsanguination - severe loss of blood
Describe when oedema occurs and what happens
When the hydrostatic pressure > oncotic pressure at the venule end of capillaries
Interstitial fluid is retained instead of returning back into the capillaries
