Most nursing schools
have "pre-reqs", which by definition must be taken prior.
However what those pre-reqs are varies from place to place. The program I went to was designed for students to come fresh out of high school, the only "pre-reqs" were high school chemistry and algerbra. If one didn't have those in high school, or didn't do well on the placement tests, then they could take them at the college level.
Now, with the competetive nature of schools, long waiting lists, schools have added more and more "pre-reqs" such as A&P, etc. It's to the point now that ADN's are now taking over 3 years to get the degree that used to be done in two years.
The LPN programs here are all-inclusive, without pre-reqs and teach the A&P, etc. alongside the nursing ciriculum.
In some schools theses courses are "co-reqs" and can be taken alongside the nursing ciriculum.