Intro To The Lymphatic System And Its Diseases Flashcards
Is the lymphatic system open or closed?
Open
Give 3 features of lymphatic capillaries
Blind ended
No smooth muscle
Incontinuous basement membrane
Give 3 features of collecting vessels
Smooth muscle coverage
Luminal valves
Basement membranes
What is a pumping unit?
Segment of lymphatic vessels between two valves
What does lymphatic drainage begin with?
The absorption of fluid from tissues
What do lymph nodes do?
Filter the lymph and interact with the immune system
What is lymph?
Interstitial fluid containing salts, proteins and cells, originally formed from plasma ultrafiltrate
What are lymph nodes?
Filter stations positioned at intervals along the lymph drainage route
What is another word for interstitial?
tissue
What two basic functions do lymph nodes perform?
Cleaning the lymph before it re-enters the blood stream
Monitoring the lymph for signs of infections
What are the three functions of the lymphatic system?
Fluid balance
Immune function
Fat absorption
What controls the amount of fluid in a blood vessel?
The balance of forces in terms of hydrostatic pressure and osmotic pressure of proteins in the blood
Where is the bulk of the fluid from the blood system drained into?
Lymphatic capillaries
Does reabsorption take place along the blood vessel?
Not at homeostasis
What is the rate limiting step for fluid drainage?
The lymphatic system
What is oedema?
Fluid swelling of a tissue
What causes chronic oedema?
Lymphatic failure (either lymph drainage is insufficient or the lymph load exceeds the capacity)
What are the three mechanisms for chronic oedema?
Lymph failure with increased capillary filtration (high lymph load overwhelming drainage capacity)
Lymph failure with no increase in capillary function
Lymph failure resulting from sustained increased capillary filtration exhausting lymph drainage capacity
What causes venous oedema?
High lymph load from venous hypotension overwhelming lymph drainage
What does lymphoedema cause?
Swelling due to build up of fluid, cells and fat, as well as a predisposition to infections
Why does lymphoedema often happen following breast cancer?
Generally you remove a lymph gland to stop the cancer spread but this increases risk of overwhelming that drainage route and the patient developing arm swelling
What causes elephantiasis?
A mosquito bite-transmitted parasite that damages or blocks the lymph system in the groin
What are the symptoms of elephantiasis?
Leg swelling
When does post-thrombotic syndrome occur?
After a DVT
Why does post-thrombotic syndrome occur?
The veins are so damaged, they cant drain fluid any more
Why does lymphoedema follow heart failure?
The pressure in the veins entering the heart builds. The higher venous pressure backs up the lymph capillaries in the leg
How is the lymphatic system related to immune function?
Once the immune cells interact with an antigen, they drain to the lymph system for immune processing
How does the gut absorb fat?
Through the lymphatic system which takes it to the bloodstream for redistribution
What does the lymphatic system do when fat is needed?
Mobilises it from peripheral and subcutaneous fat
What happens with fat when there’s a lymphatic system blockage?
It builds up
What relation does obesity have to the lymphatic system?
Obesity could be caused by bad lymph drainage (one option- not always!)
What is a sentinel lymph node biopsy designed to do?
Detect the lymphatic spread of cancer and guide treatment
What is podiconiosis?
When the lymph vessels become poisoned from silicates in the soil entering the skin and lymph system when children walk barefoot
What can cause primary chronic lymphoedema?
Developmental abnormality of the lymphatic system (generally genetic)
How do we currently manage lymphoedema?
Physio and pressure therapies intended to stimulate lymph drainage and reduce blood vascular filtration
