YPE循环系统.ppt

SPECIAL HISTOLOGY INTRODUCTION General features of blood vessels The wall of blood vessels are composed of 3 layers from the lumen outward. GENERAL FEATURES OF BLOOD VESSELS INTRODUCTION General features of blood vessels The wall of blood vessels are composed of 3 layers from the lumen outward. Tunica intima Endothelium Subendothelial layer Internal elastic membrane Tunica media Tunica adventitia ★External elastic membrane Artery Arteries are classified into three types on the basis of size and the characteristics of the structures Large artery Medium-sized artery Small artery Arteriole ARTERY ? LARGE ARTERY Large artery (elastic artery) Aorta, pulmonary arteries, innominate arteries, common carotid arteries, subclavian arteries, vertebral arteries and common iliac arteries Main features: have multiple sheets of elastic membranes ARTERY ? LARGE ARTERY 1.Tunica intima Endothelium: rich in Weibel-Palade bodies Subendothelial layer Internal elastic membrane: not prominent ARTERY ? MEDIUM-SIZED ARTERY Medium-sized artery (muscular artery) ※※ Most of the “named” arteries of the body except large artery Main features: the tunica media is composed of smooth muscle ARTERY ? MEDIUM-SIZED ARTERY 1.Tunica intima Endothelium: few Weibel-Palade bodies Subendothelial layer Internal elastic membrane: prominent ARTERY Relationships between structure and function of artery Large artery: rich in elastic membranes, facilitate the continuous and uniform movement of blood Distend during systole Contract during diastole Medium-sized artery: rich in smooth muscle, regulate blood distribution in organs Small artery and arteriole: regulate peripheral resistance CAPILLARY Classification (according to the ultrastructure) Continuous capillary Fenestrated capillary Sinusoid (sinusoid capillary) Classification of capillary 3 types of cells Pacemaker cell Transitional cell Purkinje fiber Pacemaker cell (P cell) Distribution: SA node AV node Structure: Small, fusiform or polygo