First, there is an amazing knitted replica of the human brain. Along with being quirky and colorful, it's also anatomically correct. If you're interested in this creation by Karen Norberg, check out this Scientific American article.
blog if you want to know more about him or his other anatomical knits.
Curious about knitting your own digestive system? Don't worry about it being uncharted territory; Matie Trewe has gone to the effort to write down the pattern. Although the blog has "expired" you can still get it via the Way Back Machine by clicking here.
The next anatomical knit is by Emily Stoneking, and I fear that she may not make it to regresty's page only due to talent. Then again if she is featured, it will probably be in the same warm fuzzy light that was shed on a review of Ben Cuevas's work. Her work, entitled Biology 101, has me longing to watch prosections of knitting creatures (even if he does kinda remind me of Kermit).