Physiology (Lymphatic system)

Allahuakbar. Let see how lymphatic system in our body do their work ;) (Physiologically)

Bismillahirahmanirrahim..

Asalamua'laikum everyone..I've already share with all of you about lymphoid tissue where we can view it histologically. Now, I'd like to share it in a slight different view; physiologically. :)

Ok.. first, we need to talk about:
 'Lymphatic system organization'

-Actually, lymphatic system is an accessory route to drain fluid from the interstitial space into blood. 

-It carry protein and large particulate matter that cannot enter the capillaries.
-All tisuue in our body got lymphatic system, except :
*CNS (Central Nervous System), 

*Superficial portion of the skin
*endomysium of muscle & bones
($cause they already have "prelymphatics"$)

And then..

Lymph will drain into two parts of our body:
1. Thoracic duct

-Lymph will drain from; lower part of the body, left side of head,neck, and chest.
-They will drain into Left internal jugular and subclavian vein

2. Right lymphatic duct
- Lymph will drain from; Right side of head, neck and chest

-They will lastly drain into Right internal jugular and subclavian vein.

Now, we move to :
"Lymphatic Circulation"

This time, we need to talk about Lymphatic vessel. Actually, lymphatic vessel function is to drain back lymph (interstitial fluid)back  into blood stream.

But how they do it?

Ok.. first,we must know that unlike artery, lymphatic vessel don't have pump to pump the lymph in reverse direction. In order to move the lymph, lymphatic channel have:

-contraction and relaxation of smooth muscle

-then, they have valve

-and by the help adjacent arterial pulsation

After we know about how lymph flow in our lymphatic system, lets discuss about one of the vessel in lymphatic system, that is : Lymphatic Capillaries.

How about the structure? Can you tell me? ok..let me tell you :D

Lymphatic capillaries actually function to permit passage of high molecular weight substance into the lymph.They have:

- Anchoring filament ; attach endothelial cells surrounding into connective tissue

-Valve : Endothelial cell overlap, and free edge flap inward.

-Actomysin filament : Contractile filament for rhytmic contraction

In steps, they'll do it like this:
1. Valves will trap the lymph. Not to let the lymph flow backwards.

2.Contraction of anchoring filament.

3.Contraction of contractile filament (actomysin filament)

Where actually valve presence along lympahtic vessel in certain area in our body? Ok let me tell u :)
1. In intestine; valve presence restricted to EXIT of lymphatic vessel

2.In skin and skeletal muscle, valve presence THROUGHOUT the lymphatic vessel.

Ok.. we're done with lymphatic circulation..

Now let me tell you about :
"Lymph Composition"

Actually, composition of lymph not so different with blood plasma. At terminal, lymph composition quite similar as interstitial fluid. But it differs according to which tissue it drains.

For example, in terms of Protein concentration:
-In Interstitial fluid, it is - 2g/dl

-Lymph form in liver as high as - 6g/dl

-     ,,                intestine  ,,       - 3-4 g/dl

-     ,,                thoracic   ,,       - 3-5 g/dl

Lymph, is major routes for absorption of FAT from GIT and other large particle e.g. bacteria.

How do lymph form?

Actually, lymph come from interstitial fluid.

1. Increase in interstitial fluid protein

2. Cause increase in colloid osmotic pressure.

3. Favor fluid attraction into interstitial space

4. Increase both volume and pressure of interstitial fluid.
5 As pressure of interstitial fluid increase, the lymph flow also increase

6. Carries away excess of interstitial fluid and protein

The relationship between lymph flow and inerstitial fluid pressure is :
The higher the interstitial fluid pressure, the higher the lymph flow.

When the pressure is (-), then, the lymph flow is just normal. As the pressure lose (-) and start gain (+), then, lymph flow increase and if over excessive, it can cause 'edema' (swelling in skin due to accumulation of fluid)

Is there any factors that can increase lymph flow?

Yes of course..

1. Anything that increase interstitial fluid, will also increase lymph flow.

2. Lymphatic 'pump'.
-Contraction & relaxation of smooth muscle

-external factors that compress the lymph vessel : e.g. contraction of surrounding skeletal muscle and arteries pulsation.Movement of the part of the body and etc

-Lympahtic capillary pump (actomysin filament)

How to calculate rate lymph flow?
 ok, this is it;

Rate of lymph flow = Product of interstitial fluid pressure X acyivity of lymph pump

1/10 fluids enter back to blood stream through lymphatic system rather than venous system

100 ml flows through thoracic duct

20 ml flows into circulation

Thus, total, our lymph flow is 120 ml / hour or equal to 2-3 L each day.

Thus, the main funtion of lymphatic system also :: "Controlling"
It control : volume, pressure and protein concentration of interstitial fluid and also.

Not only that,it also a "Drainage system" that expel dead cells, bacteria, and other waste and filter the lymph before it is return into the blood.

Last, al "Immune system". It produce lymphocyte to combat infection.

Disorders relate with lymphatic system is :

1. Filariasis :obstruction of lymphatic system (Lymphedema)

2. Lymphadenopathy : Increase in size of lymph nodes

3.Lymphadenitis / Lymphangitis : Inflammation of the lymph nodes.

4.Lymphoma : cancer that arise from lymph node.

Ok my fren.. :) I think, its enough for now. Don't forget to say Alhamdulillah as much as possible for the lymphatic system that Allah gave us ;) Physiologically, it help us in maintainig our body circulation ;)

Good morning~ and read with LOVE ;)