Lymphatic system Flashcards
Function of lymphatic system
- removes excess tissue fluid
- transportation of fats
- immune defence
Describe what is found in tissue fluid
- more lymphocytes than blood
- pathogens, cell products and cell debris
Describe lymph vessel structure
have very thin walls, contain valves that prevent back flow
What happens in primary lymphoid tissues
where lymphocytes are produced and mature into B and T cells
Where are B cells produced
Primary Lymphoid tissues- Bone marrow and Bursa of Fabricius (birds)
Where are T cells produced
Primary lymphoid tissue- Thymus
What is the function of Secondary Lymphatic Tissues
Where lymphocytes are activated
List secondary lymphatic tissues
- spleen
- lymph nodes
- mucose associated lymphoid tissue (MALT)
- Peyer’s patches
Describe the Thymus
- primary lymphoid organ
- Larger in younger animals and regresses with age
Where is the thymus found?
is found cranial to the heart and in birds is in the neck
Where does the thoracic duct originate and drain
Originates from the cisterna chyle
Drains into the vena cava
What is chyle
Lymph from the digestive system which contains emulsified fats
Describe the histological features of the thymus
- Has cortex and medulla
- Connective tissue capsule and strands form incomplete lobules
- Hassall’s corpuscle
Describe the histological features of the spleen
Has: - smooth muscle capsule - trabeculae central arteries red and white pulp
Describe the histological features of lymph nodes
Has:
- capsule and subcapsular sinus
- cortex- B cell centres
- High endothelial venules (HEVs)
