How can I learn anatomy and physiology?
Study a lot.
Anatomy requires a lot of memorization. Use flash cards or Quizlet and go through the information often. Learn the information from class right away after class and review it every day.
Physiology also requires memorization, but you must really understand the function of the the different organs. Read the book before you go to class so you know what you understand and what you need to get out of the class session. If you don't understand something, be sure to ask. If you read the book in preparation for class, you will know what to ask. Don't be shy about asking questions. If you are wondering about something, most likely many of the other students are too.
Here's my only advice.
I tell this to anybody who will listen to me - it doesn't matter if you're bad at drawing or not, just do what you can. Use Google's image search to find an image of an organ or body part that is most visually appealing to you, and then trace it, copy it, simplify it; whatever works for you.
Memorisation will only get you so far in this subject, and whilst there are a lot of important details you'll need to memorise, it's much more useful to able to picture the anatomy and to understand the way it works through the process of visualisation.
So dig out your pencils, draw the structure you're interested in, label as many of the details as you can, throw in some little notes or arrows, and then give it lots of colour. You'll have it down in no time.
Once you've drawn a bunch of nice images, keep them all together. Then challenge yourself to do draw quick outlines from memory, writing in the details as you go! It's addictive.