401k: Why does dividend/Capital Gains distributions lower the price/share of a 401k fund?

I know that when there is a dividend and capital gains distribution in a 401k fund, the event lowers the price/share of the fund itself..

My question is why? And please explain it to me like I’m reading an idiots guide to 401k’s… I’m not up to par on financial/economics jargon.

Asking because I just saw a $14,000 distribution into my 401k from dividends and capital gains distributions and reinvestment, but the price/share of the fund itself dropped quite a bit, lowering it by over $1.00/share