what is type 1 alveolar cells?

Answer 1

I just learned this in medical school.

They are a type of lung cell.

They compose 95% of the lung wall, but they are less numerous than type II alveolar cells.

They function as part of the blood/air barrier.

Answer 2

In the lung, part of the alveoli air sacs, the epithelium flat cells with attenuated cytoplasm and few organelles. (If you need more help with the words, click on my avatar here on the left of this answer and then click on my e-mail option in upper left part of page and send me a message. I'll add more detail here as you ask.)