W11 Intro to lymphatic system

Question 1

What is the Lymphatic System?

Answer 1

the lymphatic system acts as a countercurrent system draining from the tissues all waste materials and recycling surplus fluid, salts, proteins, fat and immune cells back to body

the Lymphatic System is the cleansing system

Question 2

The lymphatic system (Drainage)

Answer 2

a network of drainage tubes connected to lymph glands which act as drainage channels for the body’s tissues

one way drainage system

Starting with small blind ending tubes like sea anemones they drain into small streams and then ever bigger channels drain to lymph glands and beyond before eventually draining back into the blood circulation in the great vveins of the neck

Question 3

Lymphatic system appearen

Answer 3

Dermal lymphatic vascular network

Lymphatic capillaries (initial lymphatics):
Blind ended
No smooth muscle
Incontinuous basement membrane

Collecting vessels:
Smooth muscle coverage
Luminal valves
Basement membrane

Question 4

Initial lymphatics absorb …

Answer 4

Initial lymphatics absorb fluid, salts, proteins and cells from the tissues to make lymph.

Question 5

Lymp is transported to?

Answer 5

transported down bigger lymphatic vessels which actually contract so pumping lymph onwards

Question 6

Valves ensure?

Answer 6

Valves ensure lymph flow is in one direction (downstream) to the lymph glands (nodes) and beyond

Question 7

Once absorbed into initial lymphatics lymph …

Answer 7

Once absorbed into initial lymphatics lymph is pumped up the leg because larger lymphatic vessel contract in a similar way to our main heart

Question 8

Lymph nodes filter…

Answer 8

filter the lymph where there is also interaction with the immune system

Question 9

Discharging lymph

Answer 9

After passing through a series of lymph nodes large lymphatic vessels eventually discharge lymph into great veins of the neck

Question 10

What is Lymph?

Answer 10

Lymph is interstitial (tissue) fluid containing salts, proteins and cells,
originally formed from a plasma ultrafiltrate

Question 11

What are Lymph Nodes (Glands)?

Answer 11

Lymph glands are filter stations positioned at intervals along the lymph drainage route

Question 12

Lymph nodes function

Answer 12

To clean up the lymph before it re-enters the blood stream, by sieving out, trapping and destroying (inorganic) foreign materials

Monitoring the lymph for tell tale signs of (organic) predators e.g.infection, so playing a vital role in our immune system responses

Question 13

The first function of the Lymphatic System

Answer 13

The first function of the Lymphatic System is fluid balance(homeostasis)

           ‘Clears away the mess the CVS leaves behind!’

Question 14

Lymp facts

Answer 14

Upwards of 8 litres a day of plasma is filtered into the tissues and then reabsorbed almost entirely by the lymph drainage

Question 15

Steady state

Answer 15

all vascular filtrate/interstitial fluid drains via the lymphatic with only periods of transient reabsorption directly back into the blood circulation.

So any build up of fluid in the tissues for any length of time i.e. oedema, represents a failure of the lymph system to do its job properly i.e. act as an overflow pipe

Question 16

CHRONIC OEDEMA

Answer 16

= LYMPHATIC FAILURE

Either lymph drainage is insufficient or lymph load (vascular fluid filtration) exceeds lymph drainage capacity

Question 17

A swollen ankle

Answer 17

e.g. in the heat or after a long haul flight, is not normal and always means lymph drainage is not keeping up with fluid filtration (lymph load) from the blood vessels

Question 18

Lymphatic failure with increased capillary filtration

Answer 18

(high lymph load overwhelming lymph drainage capacity) = relative lymphatic failure

Question 19

Lymphatic failure with no increase in capillary filtration

Answer 19

(normal lymph load) = absolute lymphatic failure (lymphoedema)

Question 20

Lymphatic failure resulting from sustained increased capillary filtration

Answer 20

exhausting lymph drainage capacity = absolute lymphatic failure (lymphoedema)

Question 21

Chronic venous disease and oedema

Answer 21

higher volume of fluid leaving the blood vessels (small veins and capillaries) and entering the tissues of the feet, ankles and legs

has to be drained from the tissues by the lymph

If lymph drainage overwhelmed = venous oedema

but rate limiting step = lymph drainage

Question 22

Chronic venous disease and no oedema

Answer 22

If the lymph drainage is robust no oedema occurs despite the high volumes of fluid entering

Question 23

Breast cancer related lymphoedema

Answer 23

commonest disease (of lymph)

chronic swelling due to lymph drainage failure

Question 24

If oedema persists after treatment of the veins….

Answer 24

then the lymph drainage is permanently damaged and a state of lymphoedema now exists

Question 25

Lymphoedema following treated heart failure

Answer 25

Eventual and permanent failure of lymph drainage from high sustained lymph load (equivalent to hypertensive heart failure

Question 26

The second function of the Lymphatic

Answer 26

tissue immunity

The Lymphatic System houses the immune system and is responsible for tissue immunosurveillance

A common complication of impaired lymph drainage is disturbed immune cell trafficking and infections

Question 27

Cellulitis (erysipelas)

Answer 27

Cellulitis frequently reflects a problem with lymph drainage. Recurrent cellulitis always means a problem with lymph drainage

Question 28

The dermal lymphatic holds ?

Answer 28

The dermal lymphatic holds centre stage immunologically in any tissue

Question 29

The third function of the Lymphatic System

Answer 29

is fat homeostasis

The Lymphatic System is responsible for gut fat absorption and peripheral fat resorption

Question 30

The intestinal lymphatic system is responsible for ?

Answer 30

for absorption of dietary fat. Disturbances in lacteal function lead to malabsorption.

Question 31

Impaired lymph drainage in peripheral tissues

Answer 31

results in a build up of subcutaneous fat as seen in Breast Cancer Related Lymphoedema.

Lymphoedema which arises from a failure of lymph drainage is not just a fluid problem

Question 32

Close relationship between fat and lymphatics

Answer 32

The lymph system appears important for fat homeostasis. Obesity impairs lymphatic function.

Question 33

Lymphoedema occurs when

Answer 33

when the lymphatic system fails

Question 34

Lymphoedema results

Answer 34

in swelling such as a leg with build up of fluid, cells and fat, as well as a predisposition to infections

Question 35

podoconiosis

Answer 35

Here lymph vessels become poisoned from silicates in the soil entering the skin and lymph system when children walk barefoot.

Question 36

Chronic oedema caused by

Answer 36

by a developmental abnormality of the lymphatic system

Question 37

Damage to lymph drainage is known as

Answer 37

secondary lymphoedema

Question 38

Primary lymphoedema

Answer 38

when lymphoedema occurs for reasons of of an intrinsic fault in drainage and may be much more common than generally realised

Question 39

What is the management of lymphoedema/chronic oedema?

Answer 39

not one drug or one operation known to improve lymph drainage

treatment = physically based, to stimulate lymph drainage and reduce blood vascular filtration (lymph load)

Question 40

The structural basis of the active lymph transport system:

Answer 40

Intraluminal valves
- unidirectional flow
Lymphatic smooth muscle
- pumping

Question 41

Respiratory disease:

Answer 41

Asthma, Chronic airways disease

Question 42

CVS :

Answer 42

Hypertension, Plasma volume homeostasis, Atherosclerosis

Question 43

CNS

Answer 43

Glaucoma, Dementia

Question 44

Infection and Immunity

Answer 44

HIV, Organ rejection, Autoimmunity, Cellulitis, Sepsis, wound healing, tissue repair

Question 45

GI

Answer 45

Crohn’s disease

Question 46

Other Diseases of Lymphatic Dysfunction

Answer 46

Cancer Metastases

Obesity and Hypercholesterolaemia