A: Lymphatic system Flashcards
Functions of lymphatics and immune system
- Draining excess interstitial fluid to bloodstream
- Transporting dietary lipids
- Immune response
How does the interstitial fluid re-enter circulation?
- Through capillaries at venous ends
- Lymphatic capillaries carry lymph from tissues to blood stream
What % of tissue fluid is returned to circulation?
10-20%
What enters lymph capillaries?
- Tissue fluid
- Bacteria, viruses, cancer cells
From what tissues are lymph capillaries absent?
- CNS
- Bone marrow
- Avascular tissues like: nails, epidermis, cornea, hair, articular and other cartilages
Give the name for specialized lymphatic capillaries, their location and what they receive
- Lacteals
- Located in villi of small intestine
- Receive digested fats (fatty lymph = chyle)
Where do lymphatics of skin drain?
Into nodes where limbs are attached to the trunk
(They run independently of other vessels, but lymph nodes are associated with arteries and veins)
Function of lymph nodes
- Lymph percolates through LN
- Antigens destroyed and activate B and T lymphocytes
Lymph passes through series of nodes, except lymph from:
- Paired viscera on posterior abdominal wall (kidney, ovary, testis): drains directly to para-aortic nodes without being filter in any outlying nodes
- Thyroid gland: may drain directly into veins without any nodes
Name the major lymph vessels and what they drain
- Right and left jugular trunks (draining head + neck)
- Right and left subclavian trunks (draining ULs)
- Right and left bronchomediastinal trunks (draining thoracic cavity)
- Thoracic duct (drains most of lymph below diaphragm + some posterior thoracic structures
Where does all lymph eventually drain into?
- Right lymphatic duct (20% of pop, 3 trunks on right side unite): drains right side of head, right UL, right side of thorax
- Thoracic duct: drains remainder of body
Explain course of thoracic duct
- Begins as Cisterna chyli
- Ascends along vertebral bodies
- Empties into venous circulation at junction between left IJV and left subclavian vein
Where is the right lymphatic duct emptied?
Empties into right IJV and right subclavian vein
Factors which propel lymph towards venous system
- Contraction of skeletal muscle
- Arterial pulse
Function of thymus
Lymphocyte maturation (immature lymphocytes develop into T lymphocytes)
Function of tonsils
- Form a ring around border between oral cavity and pharynx
- Gather and remove pathogens
Identify
Functions of spleen
- Detects and responds to foreign substances
- Destroys defective RBCs
- Limited reservoir for blood
What could be the consequences to the spleen following a rib fracture during an RTA?
Fracture to the rib can injure spleen because it’s in left side of abdomen –> can cause haemorrhage cause spleen is a very vascular organ
Where are Peyer’s patches located?
Distal part of small intestine
Function of Peyer’s patches and appendix
- Fight invading bacteria
- MALT (mucose associated lymphoid tissue) = abundant in walls of intestines
Chylothorax
Leakage of fatty lymph (chyle) into thorax
Mononucleosis
- Viral diseased caused by Epstein-Barr virus
- Attacks B lymphocytes
Lymphangitis
Inflammation of a lymph vessel
Effects of acute infection on draining LN vs lymphatics
- LN = enlarged, tender and painful
- Lymphatics = tender, reddened streaks (lymphangitis)
Hodgkin’s disease
Malignancy of lymph nodes
Non-Hodgkin’s lymphoma
Uncontrolled multiplication and metastasis of undifferentiated lymphocytes
What happens when tumours of epithelia enter draining LNs?
- Malignant cells form metastases (secondary deposits)
- LN is enlarged, but not tender
