Any major college bookstore will have the latest and most accurate biology textbooks.
You can browse most any college bookstore without being a student.
You'll find the books (especially biology books) to be extremely expensive at a college bookstore, but you can then find the title(s) of the books that interested you the most online at Amazon, eBay, used bookstores, online college bookstore websites, etc, for far less prices -- or just rent it in an online edition for even less for a few months at www.coursesmart.com
Any current freshman college biology book by Peter Raven, et al, will give you all that you want to know.
This is the current freshman biology textbook for most classes at the University of Texas:
Biology, 10th Edition
eText: ISBN-13 9780077440183, ISBN-10 0077440188
Print: ISBN-10 0073383074, ISBN-13 9780073383071
Author(s): Raven, Peter; Johnson, George; Mason, Kenneth; Losos, Jonathan; Singer, Susan
Publisher: McGraw-Hill Higher Education
Copyright year: © 2014 Pages: 1408
And specifically for human physiology:
Essentials of Human Anatomy & Physiology, Eleventh Edition
eText: ISBN-13 9780321943576, ISBN-10 0321943570
Print: ISBN-10 0-321-91900-9, ISBN-13 978-0-321-91900-7
Author(s): Elaine N. Marieb
Publisher: Pearson
Copyright year: © 2015 Pages: 656
Edited by trance, 28 September 2014 - 04:55 AM.