Tunica intima

The tunica intima (from Latin tunica = " robe " and Intimus " the heart " ), also called tunica interna (from Latin inter = " the interior ", " located inside" ), is the inner layer of blood and lymphatic vessels.

Construction

Outwardly, viewed from the lumen of borders, the tunica intima to the tunica media.

Function

To enable the best possible blood flow, endothelial cells provide a smooth inner surface. The directed towards the lumen surface usually repels the solid blood components such as erythrocytes and leukocytes. But for example, the erythrocytes can attach to a damaged endothelium. Among other things, during inflammation. By then produced by the endothelial cell adhesion molecules other cells can attach to the wall of the blood vessel. The endothelium also provides a selectively permeable barrier for dissolved blood components dar. It also sets vasoconstrictor and vasodilator substances such as, for example, nitric oxide ( NO), free.

The average thickness of the tunica interna, depending on the blood vessel, be 7-140 microns.

The endothelium controls the interactions with the blood and the surrounding tissue itself The main functions are the regulation of Gefäßwandtonus, the antithrombogenic effect and control of Exchanges. As well as the endothelium plays an important role in blood clotting ( hemostasis ). However, it is also responsible for the development of pathological conditions with. Many active substances or precursors are contained in the endothelium .. These substances act on the fibrinolytic system. The program stored in endothelial heparin sulfate and thrombomodulin are two important substances with antikoagulatorischem potential. The endothelium is separated by a thin basement membrane from the subendothelial loose connective tissue. This contains elastic fibers, fibroblasts, smooth muscle fibers as well as individual ( myointimal cells).

Pathology

A tear of the tunica intima, with subsequent washout by the blood stream, is a dissection. After injury to the tunica intima may lead to intimal hyperplasia.

Additional images

Illustration of a vein

Anatomy of the arterial wall

With hematoxylin- eosin stained preparation of an arterial wall with calcified atherosclerotic plaque