Session 1 - Lymphatic system Flashcards
What does the lymphatic system consist of?
- Lymphatic capillaries and vessels
* Lymphoid tissues and organs
What is the function of the lymphatic system?
- Innate immunity
- Adaptive immunity
- The allergic response
What is the purpose of lymphatic capillaries and vessels?
• Fluid moves out of the tissue fluid and blood and needs to be reabsorbed
What are lymphatic capillaries and vessels?
• A network of vessels that assist in circulating fluids
What are the functions of lymphatic capillaries and vessels?
• Transport excess fluid away from interstitial spaces
How is the lymphatic system different from the CVS?
• Lymphatic system moves in a one way direction
Describe the structure of the lymphatic capillaries
- Tiny closed end vessels consisting of simple squamous epithelium
- More permeable than blood vessels as the lack a basement membrane
Describe the structure of lymphatic vessels
- Resemble small veins
* One way valves
How is lymph pumped around lymphatic vessels
- Contraction of surrounding skeletal muscle
- Periodic contraction of smooth muscle in lymphatic vessel wall
- Pressure changes in the chest during breathing
How are lymphatic vessels similar to veins?
• One way valves
How are lymphatic vessels different from veins?
• No “pump”
What do lymphatic vessels converge and empty into?
- The right lymphatic duct
* The thoracic duct
Where does the right lymphatic duct drain from and where does it empty?
• Drains lymph from upper right limb and right half of head, neck and chest, and empties into subclavian vein
Where does the thoracic duct drain from and where does it empty?
• Drains from rest of body (other than right lymphatic duct) and empties into left subclavian vein
What are the four lymphoid organs?
- Lymph nodes
- Tonsils
- Spleen
- Thymus gland
What is a lymph node?
• Rounded structures, distributed along the lymphatic vessels
What is the structure of a lymph node?
• Cortex and medulla
Describe the cortex of a lymph node
- Outer part
* Follicles with germinal centre, containing dividing lymphocytes
Describe the medulla of a lymph node
- Inner part
* Contains phagocytic macrophages
What are the 4 lymph nodes which are important clinically?
- Inguinal lymph nodes (groin)
- Axillary lymph nodes
- Cervical lymph nodes (neck)
- Aortic chain lymph nodes
What are the three main functions of the lymphatic system?
- Fluid balance
- Fat absorption
- Defence
How much fluid moves form blood capillaries to intersitial space a day?
30L
How many litres of fluid enter lymphatic vessels from blood capillaries?
3L
What does the lymphatic system do to fat?
• Absorbs it from the digestive tract
