Lymphatic system Flashcards
What is the function of the lymphatic system
Defense, return extravascular tissue fluid to the bloodstream (manage body water)
Define lymph
Lymph is extravascular tissue fluid that has entered a lymphatic vessel. Lymph, like blood, is considered to be a fluid connective tissue.
What are the primary cells of the lymphatic system
lymphocytes
What are the functions of lymphocytes
They respond to
- Bacteria or viruses that invade the body
- Abnormal cells of the body, such as cancer cells
- Foreign proteins, such as those released by bacteria
Where do lymphocytes circulate
Lymphocytes circulate in blood. They also circulate in lymphatic vessels in lymph and populate numerous lymphoid tissues and organs.
Where do lymphatic vessels begin and end
Begin in peripheral tissues and end at connections to veins.
Where are lymphocytes produced
bone marrow
Primary lymphoid tissues and organs are what
Sites where lymphocytes are formed and become mature. They include:
• Bone marrow
• Thymus gland
Secondary lymphoid tissues and organs are what
Sites where lymphocytes are activated and reproduced (cloned). They include:
• Lymph nodes
• Tonsils
• Mucosa-associated lymphoid tissue (MALT) in the gut, respiratory, urinary and reproductive tracts
• Appendix
• Spleen
___________ carry lymph from peripheral tissues and return it to the venous system.
Lymphatic vessels
___________ are associated with nearly every tissue and organ in the body and are closely associated with blood capillary networks in tissues
Lymphatic capillaries
___________ begin as blind-end pockets rather than continuous tubes and have very thin walls
Lymph capillaries
From ____________, lymph flows into larger vessels that lead to the trunk of the body usually in association with blood vessels.
lymphatic capillaries
Like _____, lymph vessels have valves that prevent backflow of lymph in these vessels that have very low flow pressures within them
veins
_____________ are located in the subcutaneous layer deep to the skin and in the loose connective tissue just underneath epithelial layers lining the digestive, respiratory, urinary and reproductive tracts and body cavities
Superficial lymphatics
__________ accompany deep arteries and veins throughout the body
Deep lymphatics
Superficial and deep lymphatics converge to form larger vessels called _________, which drain into one of two large collecting vessels that then return lymph to the venous circulation:
• Thoracic duct
• Right lymphatic duct
lymphatic trunks
___________ empties at junction of right internal jugular and right subclavian veins
Right lymphatic duct
___________ empties into junction of the left and internal jugular and left subclavian veins
thoracic duct
What is the most inferior part of the thoracic duct
cisterna chyli
What does the cisterna chyli do?
Receives lymph from the inferior part of the abdomen, pelvis and lower extremities.
Where do lymphatic vessels begin and end
Begin in peripheral tissues and end at connections to veins.
What are specific chemical signals that stimulate the immune system called?
antigens
What are the 3 types of T cells?
Cytotoxic T cells, helper T cells, suppressor T cells
___________ attack foreign cells or cells of the body infected by viruses
Cytotoxic T cells
___________ stimulate the activation and function of different classes of lymphocytes and help to establish and control the sensitivity of an immune response
Helper T cells
__________ inhibit the activation and function of different classes of lymphocytes; the interplay between suppressor T cells and helper T cells helps to establish and control the sensitivity of an immune response
Suppressor T cells
What are the 3 classes of lymphocytes
T cells, B cells, and NK cells
When stimulated, B cells become _______, which produce and secrete ________.
- plasma cells
- antibodies
What are antibodies?
Antibodies are proteins that circulate widely in body fluids and attack targets throughout the body.
What are natural killer cells
Natural killer (NK) cells attack foreign cells, infected cells or cancer cells and play a role in continuous monitoring of peripheral tissues, sometimes called IMMUNE SURVEILLANCE.
What plays the most important role for maintaining lymphocyte populations
bone marrow
_________ production involves the bone marrow, the thymus and other peripheral lymphoid tissues
Lymphocyte
What are thymosins?
Thymosins are hormones produced by the thymus that promote the development and maturation of lymphocytes
When _____ maturation is near completion, they re-enter the bloodstream and travel to peripheral lymphoid tissues and organs
T cell
______________ protecting the epithelia of the digestive, respiratory, urinary and reproductive tracts; tonsils; lymph nodes; appendix; spleen
Mucosa-associated lymphoid tissue (MALT)
What is the function of afferent lymphatic vessels?
Afferent lymphatic vessels carry lymph to the lymph node from peripheral tissues.
Where are dendritic cells found and what are their function?
Dendritic cells are found in the space immediately deep to the capsule of the lymph node. They initiate the immune response.
What is the path of lymph flow through a lymph node?
1) Afferent lymphatics
2) Dendritic cells
3) Outer cortex
4) Deep cortex
5) Medullary sinus
6) Efferent lymphatics
Where are B cells located?
outer cortex
After the outer cortex, Lymph then flows to the deep cortex, which is dominated by ______
T cells
After the deep cortex where does lymph go?
Lymph then continues into the medullary sinus at the core of the lymph node, which contains B cells and plasma cells
What is in the medullary sinus
B cells and plasma cells
Where does filtered lymph leave the lymph nodes?
efferent lymphatic vessels, which collects lymph from the node and carries it toward the venous circulation
Where is the thymus located?
mediastinum
What is the function of the thymus
The thymus is located in the mediastinum and is the location for the production and maturation of lymphocytes. It functions this way predominately before puberty
What does the thymus do after puberty?
After puberty, the thymus gradually diminishes in size and becomes fibrous and filled with adipose through a process called INVOLUTION.
What is involution?
The shrinking of an organ. The thymus goes through involution after puberty
What is the largest lymphoid organ?
Spleen
What are the 3 functions of the spleen?
- Removes abnormal blood cells and other components of blood
- Stores iron recycled from red blood cells
- Initiates immune responses by T cells and B cells in response to antigens circulating in blood
