Hypernatremia BP question

I'm really struggling with fluids and electrolytes and am having a hard time undertstanding certain concepts. I've been browsing the internet and looking through several books, but there are some things that just won't sink in.

I'm confused why the BP is high in hypernatremia. I know that in hypovolemia since the water volume is low that means the BP will be low. I would think that in hypernatremia since the water is low in relationship to the sodium, there would be a similar relationship to the BP.

What am I missing?

Thanks!