We previously learned that arterioles have a smaller diameter than arteries.

我们以前了解到，脉的直径比脉。

On the other end, about 6000 times smaller  than you, are your small arteries permeating your whole body.

，比您约 6000 倍的脉遍布全身。

A small alley is as small to the city  as an arteriole 0.1 millimeters wide is to you.

巷对于城市来说就像0.1毫米宽的脉对于你来说样。

Arterioles also have relatively more smooth muscle in their walls, which allows them to constrict and dilate more efficiently.

脉壁上的肌肉也相对较光滑，这使它们可以更有效地收缩和扩张。

If your blood pressure happens to increase, for example, the higher pressure causes the arterioles leading to your glomeruli to stretch.

例如，如果你的血压碰巧上升，更高的压力会导致导致肾的脉伸展。

Blood flow to individual organs, or throughout the entire circulatory system, can be regulated by changing the diameter of the arterioles.

流向各个器官或整个循环系统的血液可以通过改变脉的直径来调节。

In fact, the mesangium is continuous with the smooth muscles of the afferent and efferent arterioles, and fills in the space between the loops of blood vessels, hence the name.

事实上，系膜是由入、出脉的平滑肌细胞延续而来，填满了毛细血管袢的空隙，因此得名Mes-angium。

In arterioles, a process called hyaline arteriolosclerosis is where the walls of arterioles where they develop hyaline deposits, which are the deposits of proteins, and these make them hard and inflexible.

脉会出现透明样细脉硬化，即脉的血管壁上产生了透明质酸沉积，即蛋白质沉积物，而这些物质让脉僵化变硬。

And if the weak spot ruptures in a smaller arteriole blood vessel — say, one that leads to an organ like a kidney or eye, it can lead to organ damage or failure.

如果个较的脉血管中的薄弱环节破裂——比如说，个通向肾脏或眼睛等器官的血管，它可能导致器官损伤或衰竭。

Sexual arousal triggers the parasympathetic reflex that causes arterioles in the external genitalia to dilate and fill with blood, which is actually one of the only times the parasympathetic system controls any arteriole action.

性唤起触发副交感神经反射，导致外生殖器中的脉扩张并充满血液，这实际上是副交感神经系统控制任何脉作的唯时间之。

So, in the case of hypovolemia and hypotension, the macula densa cells sense the low sodium and chloride levels and send a signal over to the juxtaglomerular cells which are located in the wall of the afferent arteriole.

因此，当血容量减少、低血压时，致密斑感受到钠、氯含量降低，传递信号给位于入脉血管壁上的旁细胞。