Lymphoid System Flashcards
Components of lymphatic system
Beaded appearance due to valves
Lymphatic vessels
Lymphatic tissues (tonsils, peyer’s patches)
Lymphoid organs (thymus, spleen, lymph nodes)
Bone marrow
Role of lymphatic system
- a drainage system
Drains excessive interstitial fluid
Transports dietary lipids (triglycerides) and fat soluble vitamins (A, D, E, and K)
Immunity
What is the cisterna chyli?
Dilated sac (retro-peritoneal) at lower end of thoracic duct which receives lymph from the intestinal trunk & two lumbar lymphatic trunks. Transports fatty chyle from intestines and thus acts as conduit for lipid digestion.
Where does the thoracic duct open?
The junction of left subclavian vein and internal jugular veins.
What is chyle?
Lymph and emulsified fats. Low pressure of lacteals in the small intestine allow for diffusion of large fatty molecules.
Where does the right lymphatic duct empty?
Into the junction of the right subclavian vein and the right internal jugular vein
What do lacteals follow?
the superior mesenteric artery
What causes lymphoedema?
Primary lymphoedema - congenital
Secondarily :-
» interstitial fluid due to high capillary blood pressure
Obstruction of lymphatic vessels (infections- eg. Filariasis), parasite infestation, lesions)
Lack of skeletal muscle contraction (paralysis)
Types of cells in lymph nodes (5)
B-cells (or B-lymphocytes) T-cells Plasma cells Macrophages Dentritic cells
What do B-Lymphocytes do?
Makes antibodies against antigens.
Develop into memory B cells after activation by antigen. Important part of adaptive immunity.
What is Splenomegaly?
Enlargement of the Spleen, commonly due to overwork. Maybe due to a disease that involves abnormal RBC to be filtered in the spleen (eg. sickle cell anaemia, immune hyperplasia, bone marrow diseases, cancers, blood flow disturbances.)
What is hyperplasia?
An increase/ proliferation in the number of cells.
It maybe a normal physiological response, or a response to a diseased state.
What is neoplasia?
The proliferation of genetically abnormal cells.
