Explain the differences in pressures at the arterial and venous ends of the capillary bed.
Roughly how much fluid leaves and reenters the blood via the capillary beds/day? How much is excess?
Arterial end: high hydrostatic pressure, low osmotic pressure, Venous end: low hydrostatic pressure, high osmotic pressure
20L/day leave, 17L/day reabsorbed, 3L interstitial fluid excess
What are the 3 main functions of the lymphatic system?
Describe the vessel path that lymph takes from the capillary bed.
1) Restoration of excess interstital fluid and proteins to blood
2) Absorption of fats and fat-soluble vitamins from digestive system and transport them to venous circulation
3) Defence against invading oganisms
Lymphatic capillary (10um) -> Lymphatic collecting vessel -> Lymph nodes -> Lymph trunk -> Lymph duct (2mm)
Discontinuous membrane so fluid can enter capillary, MORE VALVES than veins b/c lower pressure + one way movement
What is elephantitis?
Describe a lymph node.
Roundworm infection of lymph nodes blocking the lymphatic drainage so interstitial fluid builds up in tissues. Common in legs and scrotum.
Kidney shaped, vessels enter convex side and leave concave side (lymph drains out), fibrous capsule, trabeulae divide it into sections, contains lymphocytes in cortex. Nodes swell if infection detected and lymphocytes start dividing.
B: Cortex (lymphocytes!)
C: Fibrous capsule
Where does the lymphatic system start?
What forms the venous angle?
What proportion of the lymphatic system drains into the R and L venous angles?
Where do superficial lymph vessels drain to
Cisterna chyli. Then up thoracic duct and drain into venous angle.
Internal jugular vein, subclavian vein, at both sides of neck.
R: 1/4, L: 3/4
Deep lymph vessels -> major ducts in thorax
A: R lymphatic trunk
B: Venous angle
C: Thoracic duct
D: cisterna chyli
What are Virchow's nodes?
What are the 3 main collections of superficial lymphatic vessels?
Where are superficial lymphatic vessels found?
What do the superficial and deep cervical lymph nodes travel with in the neck?
L supraclavicular nodes. Abdominal cancers can often metastasise to them. (Pic).
Cervical, Axillary, Inguinal
Subcutaneous tissue and drain to deep lymphatics
Superficial with external jugular vein over SCM, drains alot of facial structures. Deep alongside internal jugular vein under SCM, form R jugular trunk.
List the cervical lymph nodes.
Where do they all drain to, and what do they drain?
What do deep cervical nodes drain?
Occipital, Retroauricular, Parotid, Buccal, Submental, Submandibular.
Superficial cervical. Tongue, tonsils, pinna, scalp, neck and throat.
Most of tongue, tonsils, pinna, parotid, oropharynx, nose, paranasal sinuses, palate, larynx, trachea, esophagus. More imp in terms of cancer
When should lymph nodes be palpable?
What is a radical neck dissection?
What 2 proceedures are used today
Fighting infection or metastasis (increase in size over time and fixed - pic).
Traditional treatment for metastatic neck disease (most imp factor for spread of head and neck carcinoma from primary sites). RND: removal of SCM, IJV, spinal accessory nerve and cervical lymph nodes.
Modified radical (1 structure left) and selected neck (leave at least 1 group of lymph nodes in neck) dissections
Label the lymph nodes A-E
D: superficial cervical
E: deep cervical
What are the 2 routes of lymphatic drainage from the breast?
What are the 5 major lymph node groups in the axilla (describe drainage)?
What is a radical masectomy?
Axillary lymph nodes (75%) and parasternal lymph nodes.
Humeral (drains from upper limb), Pectoral (drains from ant. chest, 1st ones breast drains to), Subscapular (drains from post. chest) -----> all 3 drain to central -> apical nodes at top of axilla -> supraclavicular -> R venous angle
Removal of all breast tissue, nipple, axillary lymph nodes and some pec major. RARE NOW. Modified radical masectomy: removal of breast, nipple and most axillary lymph nodes.
What is sentinel lymph node identification?
Sentinel lymph nodes = node that lymph drains to 1st from a structure. So if have tumour, ID which node its likely to pass through and thus metastasise to. Inject radioacive blue dye around tumour site -> it spreads to SLN -> dissect and remove nodes and tumor.
Lymphatic drainage of lower limbs follows which superficial routes and drains to where?
Where are the deep inguinal nodes found?
What are the 2 groups of inguinal lymph nodes?
Where do efferents from superficial lymph nodes drain to?
Follow great saphenous -> drain to superficial inguinal lymph nodes. Follow short saphenous -> drain to popliteal lymph nodes.
In femoral triangle (NAVY)
Horizontal: superficial to inguinal ligament, enter abdominal wall, perineum, and external genitalia. Horizontal lymph node clearance for vulva/scrotal cancer. (NB: penis to deeper inguinal LN and testes to preaortic LN.)
Vertical: along termination of great saphenous vein, most superficial lymphatics from leg
Deep inguinal nodes (also receive lymphatics from deep leg structures).
What do the deep lymphatics accompany?
Describe deep drainage of the thorax.
How does the thoracic duct enter the thorax and travel thereafter?
Arteries. Largely in trunk. Receive drainage from internal organs.
Most lymphatics surround lungs. Interlobar lymph vessels -> interpulmonary nodes -> bronchopulmonary nodes -> superior tracheobronchial nodes. All drain to bronchomediastinal trunks.
Through aortic hiatus and travels in posterior mediastinum between aorta and azygos vein
Where does lymph from the following drain to:
a) internal (from inner pelvic structures) and external iliac (from legs) nodes?
b) GI tract?
c) intestinal and R and L lumbar trunks
a) common iliac nodes -> lumbar nodes
b) preaortic lymph nodes (celiac, superior and inferior mesenteric)
c) cisterna chyli (beginning of thoracic duct)
NB: 3 major arteries supply gut so also have 3 groups of LN on front of aorta called preaortic LN
A: cisterna chyli
B: pre-aortic LN
C: lumbar LN
What is the largest lymphoid organ and where is it located precisely?
What is it the site of?
Spleen, in L hypochondrium, deep to 9th - 11th ribs
Lymphocyte proliferation, RBC filtration, destruction and storage so full of blood. Can live without but would be on antibiotics for life.
Label A and B
A: Splenic artery
What is the thymus, and where is it found?
What are the tonsils? What do they do?
Primary lymphoid organ, located in superior mediastinum. After puberty it undergoes progressive atrophy and replaced by fat.
Lymphoid tissue around the mouth and pharynx: palatine, lingual, pharyngeal (adenoids if enlarged), tubal tonsils. They gather and remove pathogens entering the pharynx in food/inhaled air.
What is wrong with this lady?
Lymphodema in L arm as result of masectomy. Remove axillary lymph nodes = increases chance of lymphodema but reduces chance of metastasis.