The lymphatic system

The Lymphatic System

The main functions of the lymphatic system are:

Removal of bacteria and abnormal material
Helps prevent infection
Drains away excess fluids which are then eliminated from the body.

Lymph is colourless, clear, and similar to a watery fluid resembling blood plasma which it supplies to tissues for their metabolism. It is filtered through the walls of the capillaries. In the spaces between the cells where there are no blood capillaries lymph provides nourishment.

It also carries lymphocytes – these are a type of white blood cell. There is also another type of white blood cell present which lines the inside walls of the lymph nodes. Macrophages destroy and engulf any debris, bacteria or foreign bodies carried in the lymph. They also manufacture antibodies to fight bacteria, which pass into the blood stream along with the circulating lymph. When we suffer from an infection, the lymph nodes that are nearest to the infectious site will swell (oedema) and as the white cells fight the bacteria the area tends to become tender.

The lymphatic system has no muscular pump (heart) as does the blood circulation. The lymph moves through the vessels and gets around the body through movements of large muscles contracting. Lymph travels in one direction, from body tissue back towards the heart.

Lymph vessels

Lymph vessels contain valves along their vessels to prevent lymph flowing backwards. The vessels run very close to the veins around the body, and are very similar in structure to veins.

The vessels join to form larger lymph vessels, until they eventually flow into one or two large lymphatic vessels; these are the thoracic duct (or left lymphatic duct) and the right lymphatic duct. The thoracic duct receives lymph from the left side of the head, neck, chest, abdomen and lower body. The right lymphatic duct receives lymph from the right side of the head and upper body.

These large lymph vessels then empty their contents into a vein at the base of the neck, which then empties into the vena cava. The lymph is then mixed into the venous blood as it returns to the heart.

Oedema is the swelling of the tissues. This can occur when fluids accumulate instead of returning to the blood stream.

Lymph nodes

These are usually called glands. They are tiny oval structures usually between 1mm and 25mm in length, which filter the lymph, extracting the bacteria, and defending the body by fighting against infection, destroying any harmful bacteria. Lymphocytes are found in the lymph glands, and produce the antibodies which fight against the invasion of any micro-organisms.

Lymph nodes of the head

Buccal group: these drain the eyelids, nose, skin and face.
Mandibular group: drains the lips, chin, nose and cheeks.
Mastoid group: drains the temple area and skin of the ears.
Occipital group: drains the back of the scalp and upper neck area.
Sub-mental group: drains the lower lip and chin.
Parotid group: drains the ears, eyelids and nose.

Lymph nodes of the neck

Superficial cervical group: drains the back of head and neck.
Lower deep cervical group: drains the back area of neck and scalp.

Lymph nodes of the neck and chest

These nodes are in the armpit: Axilla glands drain the various areas of the chest and arms.

The Lymphatic System: A system of fluid balance and immune defence

When plasma passes out of capillary walls into the surrounding tissues, it is called interstitial fluid and provides the necessary nourishing substances for cellular life.

This interstitial fluid contains proteins that help draw fluid across the capillary wall.

Here, it will be drawn to the hyaluronic acid content of the glycosaminoglycans gel, aiding the support of collagen, elastin fibrils and the many other cells that reside in the dermis. Some fluid will move up through the dermal/epidermal junction towards the epidermis to aid the hydration of the epidermal cells and become part of the trans-epidermal water loss (TEWL) of the epidermis.

After bathing the cells, 90-98% of the interstitial fluid re-enters the capillaries, returning to the heart through the veins. The other 2-10% returns via the lymph capillary system, which is a system of dead-end capillaries that extend into most tissues, paralleling the blood capillaries.

Lymph fluid is the nourishing fluid of the cells. The lymphatic system is not only a reservoir of organic fluids and defence system against microbial invasion. Lymph fluid is the healer of wounds, the builder of tissues and regenerator for the body.

Nutritional Function

It is in the lymphatic system that the daily metabolism, the combustion and absorption of nourishing elements coming from the intestine happen. Lymph fluid carries lipids and lipid-soluble vitamins absorbed from the gastrointestinal tract. This is one of the next most important functions of the lymphatic system.

The absorption of fats and fat-soluble vitamins from the digestion system and the subsequent transport of these substances to the venous circulation makes the lymphatic system invaluable to the health of the body and, of course, the skin. Particularly the absorption of beta-carotene (Vit A)

Metabolism of the Lymphatic System

Lymph flows slowly; there is no ‘pump’ to accelerate the flow, and it relies on body movement (like walking) to help with transportation. If the lymph flow is steady and regular, the result is a balanced metabolism. When we sleep or are sedentary for long periods of time, the lymphatic circulation becomes partly stopped. It has also been found fatigue, cold, over-exertion, and nervous tension will also slow it down.

When the lymph circulation slows down, waste products accumulate, and the lymph becomes viscous, with one of the first signs of an impaired lymphatic system is swelling in the hands and feet after periods of standing or sitting. Another indication is puffy eyes in the morning.

Because there are lymphatic capillaries not only in the sheaths around the nerves but also between the nerve bundles, the stagnant lymph exerts pressure, producing a feeling of pain on the tissues and nerve extremities.

In addition, the stagnation of the fluid will produce a feeling of fatigue and heaviness in the limbs.

The effect of an impaired lymphatic system on skin cells of the dermis is very detrimental to cell renewal and repair. As cells dry out and vital functions like wound healing diminish, the tissues are poisoned by their own waste products.

As well as regular body movement, the lymphatic system relies on a regular fluid intake, as the internal hydration of the body must be maintained at an optimum level for the formation of these vital fluids. So, it is good to advise clients to increase water intake before and after treatment.

In conditions of poor body hydration, the supply of the vital interstitial fluids to the dermis is greatly reduced. This reduction of dermal fluid will have a knock-on effect on the epidermis, resulting in poor dermal/epidermal cell function and enzyme activity.

When addressing any skin condition that is related to hydration, treatment must begin with the systems that are responsible for the movement and maintenance of body fluids. Most importantly, the lymphatic system and the circulatory system they work together and are equally important.

Impaired Lymphatic System

Swelling of the ankles, feet and fingers as an early physical indication of an impaired lymphatic system. Ankles are the first place to look and to test these areas for fluid retention; use the simple toxaemia test of pressing into the swelling, which will be apparent just above the ankle bone.

Do a very firm press into the swelling for about 30 seconds, then a quick release. Count how long it takes for shape and colour to return to the depressed area. If you have counted over 3 seconds, the probability you have an impaired lymphatic system is high.

If a client has an impaired lymphatic system, advise them there will be fluid retention around the eyes for longer. This is normal