Lymphatic System Flashcards
What does the lymphatic system consist of?
Lymphatic vessels and Lymphatic organs
What are the 3 general functions of the lymphatic system?
Returning excess tissue fluid to the bloodstream, absorbing fats from the digestive tract and transporting them to the bloodstream, and defending the body against disease.
Describe lymphatic vessels
Form a one way system that begins with lymphatic capillaries.
Describe lymphatic capillaries
Found in most areas of the body, small close-ended vessels with thin walls. They then merge into larger vessels which carry the lymph into the thoracic and lymphatic ducts.
What can happen when the lymph vessels aren’t working well?
Edema which is localized swelling cause by accumulation of fluids in the tissues. Too much fluid has been made and not enough is being drained.
Describe lymph nodes
Lymph vessels lead to many lymph nodes. These act as fillers for foreign objects or pathogens in lymph. There are white blood cell types there to fight foreign objects.
Where does lymph end up?
Vessels merge before entering one of two ducts…
Thoracic duct and right lymphatic duct.
Describe the thoracic duct
Returns lymph collected from body below thorax, left arm, left side of head and neck into the left subclavian vein.
Describe the right lymphatic duct
Returns lymph from the right arm and right side of head and neck into the right subclavian vein.
What do lymphoid organs contain?
Lymphocytes which are white blood cells involved in adaptive immunity.
What are the 2 types of lymphoid organs?
Primary lymphoid organs and secondary lymphoid organs
Describe primary lymphoid organs
Where lymphocytes develop and mature. In red bone marrow and thymus.
Describe secondary lymphoid organs
Where lymphocytes become activated. In spleen and lymph nodes.
Describe red bone marrow
Network of stem cells which develop into various white blood cells. The blood cells enter bloodstream at sinuses. B cells remain and mature in the bone marrow and T cells migrate from the bone marrow and reach the thymus.
Describe the thymus
Soft, bi-lobed organ located between the trachea and the sternum. It is the site of T cell maturation.