(Lecture 13, Chapter 15) Lymphatics Flashcards
How does the body respond to damage to its tissues and/or cells?
Inflammation, swelling due to accumulation of ECF
ECF = _____ + ________ ____
plasma + interstitial fluid
What is lymph/lymph fluid?
- Plasma and water move into surrounding interstitial fluid from blood in the capillaries
- IF is collected into lymphatic vessels, and then known as lymph
Where is lymph collected and released?
- Collected at peripheral tissues
- Empties into the venous system
Is the lymphatic system an open or closed system?
Open; lymphatic vessels aren’t directly connected to capillaries
Fluid is collected, filtered in ____ ___, and returned to the blood
lymph nodes
What are the responsibilities of cells, tissues, and organs in the lymphatic system? (2)
- Drainage (returning IF to the bloodstream)
- Immunity (enhancing the body’s ability to defend against infection, illness, and disease)
T/F: Lymph doesn’t have to be replenished/regenerated
False
Lymphatic Vessels
Carry lymph and lymphocytes from peripheral tissues to the veins
Lymph Nodes
- Monitor the composition of lymph
- engulf pathogens
- stimulate immune response
Spleen
- Monitors circulating blood
- Engulfs pathogens
- Recycles RBCs
- Stimulates immune response
Thymus
Controls development/maintenance of T cells
Lymphocytes
- Main cell type in lymphatic system
- Surrounded by lymph
- Respond to invading pathogens, abnormal body cells, foreign proteins
Lymph Capillaries
- Open-ended
- Surround blood capillaries
- Embedded in capillary bed
Structure of lymphatics
- Lymphatics have valves that form from overlapping epithelial cells, creating bulges
- Valves ensure that flow of lymph is unidirectional
- No tight junctions or basement membranes; they would prevent the flow of lymph
Lymph flow
- Aided by slow/sporadic contraction of skeletal muscle
- Movement is independent of a pump (unlike the cardiovascular system)
- Valves open when the pressure of IF in interstitial space exceed that in lymphatic capillaries
T/F: Proteins can enter both lymphatic and blood capillaries
False, they can only enter lymphatic capillaries
Substances that can easily enter/exit lymphatic capillaries (3):
- Larger particles
- Cell debris
- Pathogens
Thoracic Duct
Collects lymph from below and above/to the left of the diaphragm
Right Lymphatic Duct
Collects lymph from above/to the right of the diaphragm
What blood vessels do the thoracic duct and right lymphatic duct drain into?
Thoracic Duct: left subclavian vein
Right Lymphatic Duct: right subclavian vein
Functions of lymph nodes
- Macrophages in lymph nodes remove/destroy microorganisms and debris
- Lymph nodes filter macrophages and debris, preventing them from going to other body parts
- Activate immune mechanisms; nodes are located where lymphocytes often encounter antigens and foreign particles
How does bottleneck flow occur in lymph nodes? Why is it beneficial?
- There are many afferent lymphatic vessels and only one efferent lymphatic vessel per lymph node
- Increased residence time = more time for immune function to work
List of lymphoid organs (5)
- Spleen
- Thymus
- Tonsils
- Peyer’s patches
- Appendix
