问题 填空题

根据人体的三种血管关系示意图,回答问题:

(1)图中管壁较厚、弹性大,血流速度最快的血管是______.(填标号)

(2)手臂上的一条条“青筋”是指______血管.(填标号)

(3)图中便于血液与组织细胞进行物质交换的血管是______(填标号),该血管管壁只由______层扁平上皮细胞构成,管内血流速度最慢.

答案

血液在血管内的流动方向是:动脉→毛细血管→静脉.根据图示中血管输送血液的方向可以判断:①是动脉,②是毛细血管,③是静脉.

(1)动脉血管的管壁厚、弹性大,管内血流速度在三种血管中最快.

(2)静脉是把血液从全身各处运回心脏的血管,有的静脉与动脉伴行,位置较深,有的静脉位置较浅,在体表可以看到,如手臂上的一条条青筋,就是静脉,图中的③是静脉.

(3)毛细血管数量大,分布广,血管的内径小,仅有8--10微米,只允许红细胞单行通过,管壁非常薄,只由一层上皮细胞构成;管内血流速度最慢.这些特点有利于血液与组织细胞充分地进行物物交换.图中的②是毛细血管.

故答案为:(1)①;(2)③;(3)②;一.

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