A course page is crowded and content-rich (on a representative page, JAWS tells me, "page has 24 headings and 96 links"), and it's not easy to know where to start.
Why it matters
Sighted users can easily see that the middle column is likely primary: it's much wider than the other two, and for anyone familiar with the web it looks like content, while the other two columns look like navigation or tools.
Blind users have no way of perceiving this. The "Topic outline" header isn't very meaningful, and there's no explicit "Start here" marker.
Each course should start with a small amount of narrative. Even a "Start here" heading with copy like, "Read assignment #1 and follow the links under it" would be very helpful.