and that's what's shown in this diagram here.

这就是这张图想说明的内容
As I move from the beginning of the aorta to the end

主动脉的起始部和终末部之间
there must be some drop in pressure.

必然存在着一定的压差
Has to be, otherwise blood wouldn't flow at all

否则血液就不能流动
but there's not very much of a drop.

但这个压差并不大
Similarly, the large arteries would still have large diameters,

与此相似主要的大动脉血管直径较大
have low resistances.

内部阻力较小
Doesn't take much pressure to move a flow rate

在这些大动脉中
through those large arteries,

无需太大压力就能产生流动
so over the large arteries there's not much pressure drop either.

所以在大动脉中也不存在太大压差
This would be the branches,

这些是分支
like the main branch that goes to your arm,

像这个导向手臂的主要分支