Lymphatic drainage of the thorax Flashcards
Why do we have a lymphatic system?
- More fluid leaves blood capillaries than returns to them
- Uncompensated fluid movement from blood to the extracellular fluid would result in oedema and loss of blood volume
- Lymphatic vessels drain excess extracellular fluid back into the blood
- Ensure foreign particles come into contact with immune system
what is the lymphatic system?
- Network of tissues and organs consisting of lymph vessels, lymph nodes and lymph
- Includes tonsils, adenoids, spleen and thymus
- 600-700 lymph nodes in humans
- Filter the lymph before it returns to the circulatory system
How many lymph nodes are there in humans?
600-700
what does the lymph trunk and lymph node contain?
Lymph trunk = carry the fluid
Lymph node= have expansions that do some of the filtering
Trunks= channel Nodes= enlargements
Describe the arrangement of the lymphatics across the body. State where the lymphatics join the venous circulation.
Right upper quadrant drains into the right subclavian vein.
Other three quadrants all drain via the thoracic duct into the left subclavian vein.
What is the size of a normal lymph node?
<2.5 cm
where are lymph nodes found and what do they contain?
- Found along lymph vessels
- contain lymphocytes and macrophages
- can act upon foreign bodies in the lymph
- drainage from infected regions detectable in enlarged lymph nodes
- found in armpit, groin, neck
What is a common cause of lymphadenopathy?
Infection
What is lymph usually like?
Colourless and odourless
where is the lymph node usually enlarged in children?
It is usually enlarged in the neck in children due to the large number of respiratory infections
How is lymph from the small intestines different? What is it called?
It is opaque and milky due to absorption of fats (chylomicrons)
It is called chyle
how does the lymph move?
-no pumps exist
-moves by the action of others
Slow and sporadic – no “pump”
Maintained by action of adjacent structures
Skeletal muscles and the pulses in arteries
Unidirectional due to the presence of valves
What causes movement of lymph through the vessels?
Skeletal muscle contraction
Pulses in arteries
What prevents backflow in the vessels?
Valves
What three groups of lymph nodes does the thoracic wall drain to?
The ones that drain the anterior chest wall--- Parasternal node (inside the chest wall) Lymph drains into nodes associated with: internal thoracic arteries (parasternal) ribs (intercostal) diaphragm (diaphragmatic)
REMEMBER: lymph nodes are going upwards towards the neck.
Which larger lymph vessels do these three groups of nodes drain to?
Parasternal
-Bronchomediastinal trunks
Intercostal (upper)
-Bronchomediastinal trunks
Intercostal (lower)
-Thoracic duct
Diaphragmattic
- Brachiocephalic
- Aortic/lumbar
Superficial
-Axillary or parasternal
Where does the thoracic duct start? State the vertebral level.
It begins at the cysterna chyli - L2 begins at vertebral level
It is the main channel draining most of the body
Describe the path of ascension of the thoracic duct.
The thoracic duct ascends just to the right of midline, in between the aorta and the azygos vein. It crosses over to the left side at T5 and it then empties into the left subclavian vein.
Where do the lymphatics in the lungs drain to?
Tracheobronchial nodes - this is the largest collection of lymph nodes in the body
where does the thoracic duct empty?
-Empties into junction of left internal jugular and left subclavian vein
What do the tracheobronchial lymph vessels join with and what does this form and where are they ?
Tracheobronchial lymph vessels join the parasternal and brachiocephalic lymph vessels to form the BRONCHOMEDIASTINAL trunk. They are located around bronchi and trachea, from within lung through hilum.
Describe the lymphatic drainage of the heart.
Lymphatic drainage of the heart follows the coronary arteries and drains into the:
Tracheobronchial nodes
Brachiocephalic nodes
What do the nodes on the aorta receive lymph from?
Oesophagus, diaphragm, pericardium and liver
Where do these aortic nodes drain to?
Thoracic duct and posterior mediastinal nodes
