The Lymphatic System Flashcards
What is the lymphatic system?
The lymphatic system is a network of drainage vessels throughout the body (few exceptions – eyeball, inner ear, CNS and cartilage), series of nodes along the vessels. Returns a fluid (lymph) to the blood circulation.
What is in Lymph?
Lymph is made up from tissue fluid and small proteins, lipids (chylomicrons from gut lymphatics), damaged cells, bacteria and cancer cells.
How much lymph is produced per day?
3-4L of lymphatic fluid is produced per day.
What does the lymphatic system do?
The lymph system continuously moves remaining tissue fluid and small proteins etc. from the extracellular space back to blood circulation but it is also a route for spread of infection and malignant disease.
Describe the lymph vessels that take lymph from the tissue fluid to the veins
Lymphatic capillary – afferent lymphatic vessels (bigger but still smaller than smallest veins), lymph nodes, efferent lymphatic vessels, lymphatic trunks and then lymphatic ducts.
Why is there a difference in speed of entering a lymph node and leaving?
Fast movement into the lymph node but slow movement out to allow the node to modify the lymph. This is created due to there being only one exit but many entrances to a node.
How does lymph move in only one direction?
One direction flow from a low-pressure system, no central pump.
There are valves which assisted by passive constriction (arteries and muscles) and intrinsic constriction maintain movement in one direction.
How does lymph drain into the veins?
The lymphatic system drains lymph into venous circulation and the right and left lymphatic ducts. Left lymphatic duct is also known as the thoracic duct. Drains into the junction between the internal jugular vein and the subclavian.
Which areas of the body does each duct drain?
The right duct only does the right side of your face down to the right hemidiaphragm and all of the right upper limb, whilst the left duct drains all of the rest of the body including both legs.
Why doesn’t lymph drain into arteries?
Lymph doesn’t drain into the arteries because of the high pressure.
What is lymphoedema?
Chronic condition -abnormal collection of protein rich fluid causing tissue swelling due to compromised lymphatic system. Can be due to removal or enlargement of lymph nodes, infections, damage to lymphatic system (cancer) treatments, lack of limb movement, congenital.
Lymphoedema – non pitting oedema.
Describe lymph nodes
Connective tissue structures – tough fibrous outer capsule, inside this is the reticular connective tissues like candy floss
Contains a large collection of lymphocytes (B and T) and macrophages. Lymph nodes are lymphoid organs.
Lymph draining into lymph nodes may contain pathogens such as from an infected area of tissue. Lymph nodes play a massive role in immune defence.
Does all lymph pass through a node? What barriers are there in nodes to stop pathogens?
All lymph will pass through at least one lymph node. There is both a physical filter in terms of the reticular connective tissue and a phagocytic filter.
What causes lymphadenopathy?
Lymphadenopathy – swollen lymph nodes
Usually due to infection or more rarely malignancy.
How can you tell the difference between a swollen lymph node caused by cancer or infection?
When palpating – if infectious cause – tender and mobile, if cancerous causes the lymph node will be hard, matted, potentially immobile and non-tender.
If node is enlarged – examine the area of tissue it drains and if malignancy suspected examine other lymph nodes and body systems.
