Vessel Wall - Tissue Functioning and Remodeling in the Circulatory and Ventilatory Systems - page 351

Tabl e 7. 1. Artery wall structure. Downstream from the heart, the arterial tree successively
comprises elastic, transition, and muscular arteries, and arterioles. The different artery types act
as conducting, distributing, and resistive arteries with increasing distance from the heart. During
the systole, elastic arteries store a part of the blood volume ejected by the left ventricle for diastolic
restitution owing to wall recoil. Peripheral muscular arteries and arterioles locally control the
lumen size and the vessel resistance.
Layer Elastic Muscular Arteriole Cerebral

artery artery artery artery

Caliber Great Mid Small Mid

Intima Absence of

subendo-
thelium

IEL Thin Important, Thin Well

elastic scalloped Thin developed

lamellae

Media Thick Thin 1-5 layers Almost

Numerous Numerous of SMCs no EnFs

elastic layers

lamellae of SMCs

EEL Badly Clearly Badly Absent

defined defined defined

Adventitia Thin Thick

Tabl e 7. 2. Wall structure (EC: endothelial cell; FB: fibroblast; SMC: smooth muscle cell; Col:
collagen; Eln: elastin; FN: fibronectin; Lam: laminin; PoG: proteoglycan; Tsp: thrombospondin;
vWF: von Willebrand factor).

Wall layer Components

Endothelium EC

Basement membrane Col4, Lam

Subendothelium Col3/4/5, Lam, FN, PoG, Tsp, vWF,

FB, ± SMC

IEL Eln

Media Col, Eln, PoG,

FB, SMC

EEL Eln

Adventitia FB, Eln, Col

Vasa vasorum, nerve endings, lymphatics

The external elastic lamina is not very well defined and the adventitia is thinner.
The orientation and extension of the collagen fibers of the adventitia of human
aortas that undergo uniaxial tension are correlated to the applied stress [ 654 ]. After
straightening and suitable orientation, collagen fibers can bear increasing loads.