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Issue
40 — January 2006 |
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Pictures |
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The
skin’s blood vessel system |
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The human skin is supplied with nutrients and oxygen via a blood vessel
system. Blood supplies the skin layer where cell growth is the strongest
with nutrients. The blood vessel system of the skin functions thus provides
nutrients to the cells and tissue, helps regulate body temperature and supports
blood pressure regulation.
Our illustration shows a scematic cross-section of the blood vessel system of
the human skin. The figure shows an interconnected network of vessels which is
characterized by regular structures on all levels. The skin or integument is composed
of various layers. The integument forms the exterior skin surface. It is composed
of the skin (cutis) and the subcutis (hypodermis). The cutis is composed of two
layers, the epidermis and the dermis (corium).
The dermis and subcutis are pervaded with a complex system of blood vessels,
while the epidermis is free of vessels. The blood supply to the skin (cutaneous
blood supply) is provided for by arteries and veins which carry blood to
and away from the heart and by a microvascular vessel network. A superficial
network comprises the interface between papillary and reticular dermis,
while a lower network is located on the border between dermis and subcutis.
Vertical vessels connect both networks and thus make it complete.
In the adjoining cutis and subcutis, as well as in the papillary and the
stratum reticulare of the cutis, arteries (which are shown in red in our
diagram) and veins (in blue) form network-like structures. From here, capillary
loops arise into the papillaries of the connective tissue.
The dermis, which mainly consists of connective tissue fibres, shows closely
intertwined structures with the epidermis (papillaries). In these subpapillary
spaces, arteries and veins are very densely structured. This finely capillarized
vessel system supplies the bordering zone and the epidermis which is free
of vessels. Besides the nerves, the subcutis contains the larger blood vessels
for the upper skin layers.
The skin as the largest organ in terms of area and the heaviest organ of
the human body fulfils a multitude of tasks. One of its major functions
is its metabolic one. The skin’s blood vessel system supplies the
cells and tissue with nutrients and supports the blood pressure regulation.
A complex interplay between blood vessel system, warmth receptors of the
skin, central nervous system and sebaceous glands is in charge of regulating
the body’s heat balance.
References: Helmut Leonhardt, Histologie, Zytologie und Mikroanatomie
des Menschen, Vol. 3, Thieme, Stuttgart 1990; Peter T. Pugliese, Physiology of
the Skin II, Allured Publishing Corporation 2001
