Lymphatic system Flashcards
Lymphatic system functions
The lymphatic system moves fluid throughout the body and depends the body against disease-causing agents
- drains excess interstitial fluid
- transports dietary lipids (vitamin A, D, E, K)
- carries out immune responses
Lymph vessels
Collect excess tissue fluid and return it to venous blood
- without a “drainage” system edema in tissues increases and high fluid pressure causes tissue damage or tissue death
- this is extravascular fluid
Lymphatic system components
- lymphatic fluid - lymphatic vessels - lymph nodes - tonsils - thymus - spleen
Lymph
Lymphatic fluid
- clear, watery-appearing fluid found in the lymphatic vessels
- closely resembles blood plasma in composition
Interstitial fluid
IF
- complex fluid that fills the spaces between the cells and part of the extracellular matrix
- closely resembles blood plasma in composition
Structure of lymphatic vessels
The capillary wall is formed by a single layer of thin, flat, endothelial cells — as the diameter increases from capillary size, the walls become thicker and have three layers
- lymphatic resemble veins in structure with these exceptions
1. Thinner walls
2. More valves
3. Lymph nodes
Pics
Pic
Lymphatic vessels function
Transportation of fluid, proteins, fats, and other substances to the general circulation
- do not form a closed circuit
- lymphatic capillaries begin blindly in intercellular space
Lymphatic vessels
- lymphatic capillaries have greater permeability than blood capillaries
- large molecules are able to diffuse into lymphatic capillaries
- as lymph pressure increase, the cells of capillary walls overlap so that lymph does not move out
- lymphatic capillaries are attached to surrounding cells by connective tissue filaments
- as interstitial fluid increases, the tissue filaments are pulled and space between cells increases and fluid flows into capillary
Lymphatic vessels 2
- virtually all capillary beds contain lymphatic capillaries
- lymphatic vessels follow the venous system
- lymphatic vessels of the viscera follow arteries
- lymphatic capillaries merge to form larger lymphatic and eventually form the main lymphatic trunks
2 main ducts
- Right lymphatic duct
2. Thoracic duct (left lymphatic duct)
Right lymphatic duct
Lymph from the RUQ -> right lymphatic duct -> right subclavian vein
Thoracic duct
Lymph from the rest of the body -> thoracic duct -> left subclavian vein
Pic
Pic
Pic
Pic