Lymphatic System Flashcards
What does the lymphatic system do?
Returns interstitial fluid that has leaked from the vascular system and plasma protein back to the blood.
What are the three parts of the lymphatic system?
- Lymphatics: Network of lymphatic vessels
- Lymph: The fluid in vessels
- Lymph nodes: Cleanse the lymph
Once interstitial fluid enters lymphatics, it is called?
Lymph
What do lymphoid organs and tissues provide?
Structural basis of immune system by housing phagocytic cells and lymphocytes
(e.g. spleen, thymus, tonsils, lymph nodes, other lymphoid tissues)
Why do lymphatic vessels offer a one-way system?
To ensure lymph flows only toward heart
What 2 things do lymphatics (lymph vessels) include?
Lymphatic capillaries
Larger lymphatic vessels
What are lymphatic capillaries?
Blind-ended vessels that weave between tissue cells and blood capillaries.
Lymphatic capillaries are absent from what?
- Bones
- Teeth
- Bone marrow
How do lymphatic capillaries differ from blood capillaries?
- Similar but more permeable
- Can take up larger molecules and particles
(e.g. proteins, cell debris, pathogens and cancer cells) - Can act as a route for pathogens to travel throughout the body
What 2 specialized structures allow increased permeability of lymphatic capillaries?
- Endothelial cells overlap loosely to form one-way minivalves
- Minivalves are anchored by collagen filaments to matrix, hence increases in ECF volume opens minivalves more
What happens to the minivalves when the extracellular fluid decreases?
Close
What are lacteals and their functions?
- Specialized lymph capillaries present in the intestinal mucosa.
- Absorb digested fat and deliver fatty lymph (chyle) to blood
What do larger lymphatic vessels consist of and what’s its structure like?
- Collecting vessels, trunks and ducts.
- Similar to veins, except have thinner walls with more internal valves and anastomose more frequently.
What are the main functions of lymphatic vessels?
- Return excess tissue fluid to the blood
- Return leaked proteins to the blood
- Carry pathogens to lymph nodes
- Carry absorbed fat from the intestine to the blood (via lacteals)
Where do lymph capillaries drain into?
Collecting lymphatic vessels
Collecting vessels in skin travel with ______ veins, but deep vessels travel with _______.
- superficial
- arteries
What are lymphatic trunks formed by?
Union of largest collecting vessels
to drain large areas of the body
Name regions where larger lymphatic trunks drain.
- Paired lumber
- Paired broncho-mediastinal
- Paired subclavian
- Paired jugular trunks
- Single intestinal trunk
Lymph is delivered from trunks into what?
Two large lymphatic ducts
What does the right lymphatic ducts drain?
Right upper arm and right side of head and thorax
What does the thoracic duct drain?
The rest of the body; starts out as an enlarged sac aka cisterna chyli
What do lymphatic vessels do?
- Return excess tissue fluid to the blood
- Return leaked proteins to the blood
- Carry pathogens to lymph nodes
- Carry absorbed fat from the intestine to the blood (via lacteals)