The Capillary Bed
The capillary bed is found in the superficial dermis and is an important part of the integumentary system. It is made up of a group of capillaries which are supplied with oxygenated blood via the arterioles and drained of deoxygenated blood via the venules of the circulatory system. The pulsating flow within the capillary bed is called vasomotion. The type of circulation through the capillaries is called microcirculation
Image 1 bellow shows the components of the capillary bed.
1 Arteries, Veins and Capillaries. BBC (2014)
When the oxygenated blood travels via the arterioles into the capillaries, which are only 1 cell thick and are permeable, certain gasses and substances can flow/diffuse from the blood to the interstitial fluid and tissue cells. This process I have described is perfusion. The deoxygenated blood is then carried away via the Venules into the veins then to the heart where the blood will be pumped to the lungs to collect more oxygen.
There are three types of capillaries in the body, Continuous, Fenestrated and Discontinued (Sinusoidal). These are found in various areas of the body and allow the diffusion of different types of substances. All capillaries have a basement membrane and an endothelial layer/wall, which is endothelial cells closely packed together. The spaces between the cells are called tight junctions.
Each capillary type depends on where they are found and how much/what they allow to pass through.
Below I have made a table to define the type of capillary, its appearance and where they are found.
Capillary type Appearance Where they are found
Continuous capillaries have intercellular clefts, within the tight junctions of the endothelial cells, to allow water, ions and other very small molecules to diffuse. Mostly everywhere in the body
Fenestrated capillaries have pores that are called fenestrations as well as the tight junctions. These allow larger molecules to diffuse. In the small intestine, kidneys, brain and in the endocrine system
Discontinued (Sinusoid) capillaries Appear flattened and have openings in the basement membrane and at the tight junctions of the endothelial layer, called intercellular gaps, that allow larger molecules to diffuse. In the liver, spleen, lymph nodes, bone marrow and in the endocrine system.
Image 2 highlights the structure of each of the main capillaries
2The three major types of capillaries. OpenStax College (2016)
The capillary bed is also very important to heat regulation. This is how the body controls its temperature.
When the bodies temperature is too low the vessels constrict (vasoconstriction) to decrease the amount of blood to flow to the area (Image 3. C) which stops heat from being lost from the surface of the skin. During this the erector pili muscles (Image 3. A) contract causing the hairs to stand on end (Image 3. B), this is how we get goose bumps. This action traps heat between the hairs acting like an insulated barrier on the skin preventing the heat from escaping. This is highlighted in Image 3.
3 Controlling temperature (LOW) BBC (2014), ABPI (2016)
When the temperature of the body is too high the vessels dilate (vasodilation) to allow more blood to flow to the area (Image 4.F), releasing heat from the surface of the skin. during this the erector pili muscles (Image 4. D) relax so the hairs lie flat on the skin so heat can leave efficiently. Also the sweat glands produce sweat and secretes from the pores onto the skin (Image 4. E). As the sweat is evaporated this cools the body. Image 4 shows an example of the bodies heat regulation in sweating and reddening of the skin (erythema) as the blood is pumped to the surface of the skin.
4 Controlling Temperature (HIGH) BBC (2014), ABPI (2016)
Telangiectasia
Other names for telangiectasia
Telangiectases
Telangiectasis
Broken capillaries
Thread veins
Spider veins
Dilated capillaries
What is Telangiectasia?
Telangiectasia is a benign skin condition where the superficial blood capillaries are in a state of constant vasodilation. The vessels can be found up to 1mm in diameter and will vary from light too dark in colour depending on the severity. (Some have been reported to appear blue)
The client may feel slight discomfort or find the area slightly itchy as the vessels are under pressure but this may not be present in mild cases. \\z
Image 6 shows how a capillary would look in a state of vasodilation
The appearance usually consists of an area with a group of capillaries visible on the surface of the skin. In most cases they do not cause any harm but may be an underlying symptom of other diseases/issues within the body.
Where is telangiectasia found?
Telangiectasia is usually more commonly found on the face, normally around the nose and cheek areas, although it can be found all over the body, mainly on the legs. Telangiectasia can be fatal if it is present in the other types of capillaries that supply vital organs in the body (this is not common).
Image 5 shows an example of telangiectasia on the cheek area.
What causes Telangiectasia?
Telangiectasia can be caused by many different factors. I have composed the table below to show the various causes of telangiectasia and why they have formed.
Causes Why?
ENVIRONMENTAL CHANGES Overexposure to U.V/sun light without the appropriate SPF applied, allowing the skin to be exposed to harsh weather or dramatic temperature changes cause skin damage which cause capillaries to dilate permanently.
PREGNANCY Due to the pressure applied to the blood vessels during pregnancy.
AGING Weakening of the blood vessels as we age.
ALCOHOLISM/DRUG ABUSE Alcohol and the misuse of drugs can alter the flow of blood (Blood circulation).
ROSACEA The dilated capillaries may become permanently dilated.
HARSH PRODUCTS Using products/Incorrect use of products like steroids etc. the products may be too harsh for the client’s skin.
Treatment for telangiectasia
Telangiectasia is deemed treatable if when gentle pressure is applied to the area, the skin blanches. Treatment is available using;
Advanced epilation using the application of one of the following types of currents;
Shortwave diathermy
Blend of galvanic and shortwave diathermy
Laser and intense pulse light treatment where heat is applied via a laser/light to minimise the vessels.
Sclerotherapy (This is more effective to treat telangiectasia on the leg area) a solution is inserted into the vessel, using a syringe, causing a clotting action that heals then disappears.
Spider Naevi
Other Names for Spider Naevi
Spider Angiomas
Spider Veins
Vascular Spider
Nevus Aranius
Arterial Spider
Stellate Haemangioma
Naevus Araneus/Arachnoidius
What is spider naevi?
Spider naevi is known to be classed in the same category telangiectasia where again the superficial blood capillaries, again up to 1mm in diameter and will vary from light too dark in colour depending on the severity, are in a state of constant dilation.
Here though the capillaries surrounding capillaries get blood from the arteriole which is visible on the skin as a central point giving the appearance of the body of a spider (usually found to be raised). The capillaries that feed from this point extend outwards then giving the appearance of (the spiders) legs. The differences between telangiectasia and spider naevi are mainly the causes.
Image 7 Shows an example of spider naevi on the facial area.
Where is spider naevi found?
Spider naevi is commonly found on the face, decollate and legs. If many are present, this can be indication of liver disease and other diseases. These may appear in groups of more than five. The client may feel discomfort in the area of the spider naevi, again due to the pressure on the vessels.
What causes spider naevi?
Spider naevi have mostly the same causes as telangiectasia although I have found that spider naevi has been more precisely related to conditions like disease, obesity, pregnancy/hormonal changes and genetic history of the cardiovascular system, rather than more lifestyle related causes like exposure to harsh chemicals etc. these conditions put additional pressure on the vessels causing them to dilate.
Although it has been known that prolonged episodes of standing/sitting and U.V/Sun light overexposure can also cause spider naevi to occur.
If many are present, this can be indication of liver disease and other diseases.
Image 8 shows an example of a group/cluster of spider naevi.
Treatment for spider naevi
Similarly, to telangiectasia, when gentle pressure is applied to the area, the skin blanches. Treatment is available using;
Advanced epilation using the application of one of the following types of currents;
Shortwave diathermy
Blend of galvanic and shortwave diathermy
Laser and intense pulse light treatment where heat is applied via a laser/light to minimise the vessels.
Campbell de Morgan
Other Names for Campbell de Morgan
Blood spots
Cherry Angiomas
Cherry spots
Senile Angiomas
Haemangioma
What is Campbell de Morgan?
Campbell de Morgan is a benign skin lesion that is commonly found to be red in colour, is usually in a small circular shape and elevated on the skin (looking like a spot). A Campbell de Morgan consists of a cluster of dilated capillaries. Although here, unlike telangiectasia and spider naevi, the eye can not differentiate each capillary on its own due to being so closely packed together. These lesions can be found ranging up to 3mm in size.
Image 9 shows an example of Campbell de Morgan and how they vary in size.
Where is Campbell de Morgan found?
These are fairly common particularly for people age 30+. They are most commonly found in the torso and upper body regions, including the arms. Usually the removal of Campbell de Morgan is for cosmetic purposes although if the client experiences frequent bleeding from the Campbell de Morgan then removal may be required in some cases.
What causes Campbell de Morgan?
It has been found that age seems to be closely linked to Campbell de Morgan spots in both males and females.
Treatment for Campbell de Morgan
Here when gentle pressure is applied to the area, the skin does not blanche. Treatment is available using;
Advanced epilation using the application of one of the following types of currents;
Shortwave diathermy
Blend of galvanic and shortwave diathermy
Laser and intense pulse light treatment where heat is applied via a laser/light to minimise the vessels.
Cryotherapy to freeze the Campbell de Morgan with the application of liquid nitrogen. The lesion then falls off.
Sclerotherapy a solution is inserted into the vessel, using a syringe, causing a clotting action that heals then disappears.