Lymphatic System Flashcards
How many litres per day are collected as interstitial fluid?
3 litres
What are the vessels called in the lymph system?
Lymphatics
What cells are present in the lymph system?
Lymphocytes (B, T, Natural Killer cells)
How much fluid goes into the lymphatic system per day?
20 litres
17 reabsorbed
What are the three main parts of the Lymphatic system?
Lymph
Why doesn’t lymph contain red blood cells?
Too large to fit through the capillary membrane
What organs are important in the Lymph system?
Tonsils, Adenoids, Thymus, Spleen
Where are lymphatic capillaries not present?
Bones, bone marrow, teeth and the CNS as have own drainage system
What are lymphatic capillaries made from?
endothelial cells
Form flaplike minivalves
What causes the movement of lymph through vessels?
Skeletal muscle movement, pressure changes in the thorax while breathing and adjacent artery pulsation, large lymphatics contain smooth muscle
Where are lymphocytes found and mature?
Loose reticular connective tissue that makes up lymph nodes and some lymph organs
What are MALTs?
Mucosa associated lymphoid tissues e.g. tonsils and Peyer’s patches and vermiform appendix
What is the role of Lymph Nodes?
Serve as a filter, traps antigens, processes antigen and presents processed antigens to T cells
Where do afferent lymphatics enter?
Convex surface
Where do efferent lymphatics leave?
Hilium
What is a Follicular dendritic cell?
Located in germinal centres
form antigen antibody complexes which retain antigens for months
increase amount of memory B cells
What are Antigen presenting cells?
B cells and Macrophages that are equipped with special immonostimulatory receptors that allow for activation of T cells
What is the inflammatory response?
The initial reaction of the body to an antigen
What mediates the inflammatory response?
Neutrophils and or macrophages
What is Humoral immunity?
B lymphocytes produce antibodies tha transform into plasma cells that synthesise and secrete specific antibodies
What is cell-mediated immunity?
T cells need antigen presenting cells (macrophages and B lymphocytes) to recognise antigens
What is cell mediated immunity important in defence against?
Viral, fungal and mycobacterial infections, tumour cells and transplant rejection
What do B cells do?
Attack invaders outside cells
What do T cells do?
Attack invades inside cells
What causes lymph nodes to swell?
As lymph nodes figt infection the germinal centres fill with lymphocytes which causes swelling and pain
What is the function of the spleen?
Filters blood
Antigen presentation by APCs, activated and proliferation of B and T lymphocytes and produces antibodies, removes macromolecular antigens from blood, removed old erythrocytes and platelets, retrieves iron from haemoglobin
Why is it okay to remove the spleen?
Liver and bone marrow will destroy old blood cells
What are the problems with removing the spleen?
increases risk of infected by encapsulated bacteria and malaria, DVT and pulmonary embolism threefold
What is the role of the thymus?
Maturation of bone marrow derived stem cells into immunocompetent T cells- thymic cell education
When does the thymus become mostly fat?
late teens
