The Lymphatic System Flashcards
How many litres of interstitial fluid are collected by the lymphatic system each day? Where is this fluid returned?
3 litres (out of 20)
Returned to the venous system
Name 3 phagocytes
Macrophages, dendritic cells and neutrophils
What cells are present in the lymphatic system?
Lymphocytes (e.g. B, T and NK cells)
Supporting Cells - macrophages, follicular dendritic cells
In what part of the body are there no lymphatics?
CNS
How does lymph continue flowing in lymphatics? (2)
1) Passes through skeletal muscle, skeletal muscle contraction helps lymph to continue flowing
2) Larger lymphatics (e.g. Abdomen/thorax) contain smooth muscle, which contracts to move lymph
What can lymphoedema result in?
The presence of a static fluid can result in infections e.g. Cellulitis
How does cellulitis often present?
As redness of the skin
What are two examples of tissues in the lymphatic system?
Diffuse, MALT (mucosal associated lymphatic tissue)
Lymphatic nodules
What are two types of MALT?
GALT AND BALT
Gut and bronchus respectively
What are some examples of lymphatic nodules?
Tonsils, Peyer’s Patches, the vermiform appendix
What are the 3 organs of the lymphatic system?
Spleen, thymus and lymph nodes
What prevents the movement of essential bacteria out of the colon?
Valves
What is the function of lymph nodes?
To act as filters for the lymph
Where do afferent lymphatics enter the lymph node?
Via the convex surface
Where do efferent lymphatics leave the lymph nodes?
Via the hilum
Where are follicular dendritic cells found?
In the germinal centres of lymph follicles
What do follicular dendritic cells result in? How?
The proliferation of B cells, particularly memory B cells.
Through the adhering of antigen-antibody complexes to their processes, the cell retains the specific antigen for months.
Lymph nodes contain professional APCs. What are two examples of these? Which cells in particular do they prime?
B cells and macrophages.
Activation of T cells
What is the first reaction of the body to an antigen?
An inflammatory response
What two cells largely mediate inflammation?
Neutrophils
Macrophages
What is the humoral response mediated by? What is produced as a result of the humoral response?
B cells.
Antibodies (b cells —-> plasma cells (produce antibodies)
What is the cell mediated response mediated by?
T cells
What do T cells require to recognise an antigen?
An APC
Cell mediated immunity is important in defence against… (3)
Tumour cells
Transplant rejection
Viral/fungal infections
Where do many of the macrophages, neutrophils, B and T cells exist in the lymphatic system?
Lymph nodes
Where do the feeding artery and draining vein enter and leave the lymph node?
Via the hilum
Where do the majority of lymphocytes enter and leave the lymph nodes?
Enter in the feeding artery
Leave in the efferent lymphatics
What is the main cause of enlarged lymph nodes?
Germinal centres of lymph follicles fill with lymphocytes to fight infection, resulting in swelling and pain
How do cancers metastasise to lymph nodes?
Via the afferent lymphatics
What is the main function of the spleen?
Filters the blood in the same way that lymph nodes filter lymph
Has immune and haemapoietic functions
Give 3 haemopoietic functions of the spleen
Removes damaged/old RBCs
Removes platelets
Retrieves iron from RBC haemoglobin
Why can rupturing of the spleen result in death?
Has a rich blood supply, relatively fragile —> can result in death through extreme blood loss (exsanguination)
What is the process of removing the spleen called?
Splenectomy
What can take over the removal of ageing RBCs from the blood in the case of an absent spleen?
The liver
Bone marrow
The risk of what increases after a splenectomy?
Infection
DVT
Pulmonary Embolism
What can result in an enlarged spleen?
Systemic infection (e.g. Glandular fever)
Where is the thymus located?
In the superior mediastinum
The thymus turns into mostly fat by which age?
The late teens
What is the main function of the thymus
Thymic cell education
