ANATOMY AND PHYSIOLOGY - Lymphatic System Flashcards
What are the four components of the lymphatic system?
Lymph
Lymphatic vessels
Lymphatic ducts
Lymphoid tissues
What is the function of lymph?
Lymph is a watery liquid from the interstitial space that picks up fats, bacteria and other unwanted materials and filters these through the lymphatic system
What is the function of the primary lymphoid tissues/organs?
Lymphocyte production
What are the four primary lymphoid tissues/organs?
Bone marrow
Thymus
Foetal liver
Bursa of fabricus
In which species is the Bursa of fabricus present in?
The Bursa of fabricus is only present in birds
What is the function of the secondary lymphoid tissues/organs?
Lymphocyte activation
What are the secondary lymphoid tissues/organs?
Lymph nodes
Spleen
Tonsils
Mucosa-associated lymphoid tissue (MALT)
What are the two main functions of the lymphatic system?
Supports the cardiovascular system
Supports the immune system
How does the lymphatic system support the cardiovascular system?
The lymphatic system maintains fluid levels through returning fluid to the bloodstream
How does the lymphatic system support the immune system?
The lymphatic system filters out unwanted materials and is the site of lymphocyte production, maturation and activation
How is fluid (lymph) returned back into the systemic circulation by the lymphatic system?
Hydrostatic pressure pushes fluid out of the capillaries into the interstitial space and oncotic pressure pushes fluid from the interstitial space into the capillaries. The excess fluid left in the interstitial space, known as lymph, is collected by lymphatic capillaries which merge to form lymphatic vessels which filter the lymph through lymph nodes before travelling towards the heart. Filtered lymph drains into lymphatic ducts and into the subclavian veins, back into the systemic circulation
What are the two lymphatic ducts?
Right lymphatic duct
Thoracic lymphatic duct
Which parts of the body are drained by the right lymphatic duct?
Right thoracic cavity
Right arm
Right side of the head and neck
Which vein does the right lymphatic duct drain into?
Right subclavian vein
Which parts of the body are drained by the thoracic lymphatic duct?
The thoracic lymphatic duct drains the areas of the body the right lymphatic duct does not
Which vein does the thoracic lymphatic duct drain into?
Left subclavian vein
Unlike blood vessels, lymphatic vessels have no pressure, so how does the lymph move around the body?
Contraction of skeletal muscle during movement
Contraction of smooth muscle in lymphatic vessel walls
System of valves preventing lymph back flow
What are the specific functions of bone marrow in the lymphatic system?
Production and maturation of B-lymphocytes
Production of T-lymphocytes
What are the specific functions of the thymus in the lymphatic system?
T-lymphocyte maturation and proliferation
Where are the immature and mature T-lymphocytes found within the thymus?
The T-lymphocyte maturity increases from the cortex to the medulla of the thymus
Where does lymph enter and exit lymph nodes?
Lymph enters via afferent lymphatic vessels and exits via efferent lymphatic vessels at the hilus of the lymph node
Where are the germinal centres contained within follicles located within the lymph node?
Germinal centres contained within follicles are found within the cortex of the lymph node
Where are B-lymphocytes found within lymph nodes?
B-lymphocytes are found within the lymphoid follicles
What is the paracortical zone of the lymph nodes?
The paracortical zone is the area between the cortex and the medulla in the lymph nodes
Where are T-lymphocytes found within lymph nodes?
T-lymphocytes are found within the paracortical zone
What is the function high endothelial valves found in the lymph nodes?
High endothelial valves are modified post-capillary venues that enable lymphocytes in the blood to enter the lymph via diapedesis
What are the two main tissue types found in the spleen?
White pulp
Red pulp
What is the function of white pulp in the spleen?
White pulp is lymphoid tissue involved in immunosurveillance
What is the function of red pulp in the spleen?
Red pulp contains venous sinuses (blood filled cavities) which are lined with macrophages to phagocytose any pathogens, foreign material or senescent erythrocytes and thrombocytes
What are periarteriolar lymphoid sheaths (PALS) found in the spleen?
Periarteriolar lymphoid sheaths (PALS) are portions of white pulp surrounding the central arterioles running through the spleen
What is the function of periarteriolar lymphoid sheaths (PALS) in the spleen?
Blood must pass through the periarteriolar lymphoid sheaths (PALS) and undergo immunosurveillance before entering the red pulp to be drain by the venous sinuses
List three examples of MALT tissue
Peyer’s patches
Gut-associated lymphoid tissue (GALT)
Bronchial-associated lymphoid tissue (BALT)
