The majority of my students are either out of state or international students who live on campus during the regular academic year and return home during the summer months. Thus, most students cannot attend face-to-face summer classes held on campus. In 2015, I developed a flipped, completely online human physiology course to meet the needs of these students. Human Physiology Online is composed of an asynchronous portion, where students review course material on their own (out of sync), and a synchronous portion, when we all meet online at the same time (in sync). Here, I describe the asynchronous and synchronous components of Human Physiology Online in detail, including how I use technology to recreate the small group environment of my regular face-to-face class during synchronous class sessions. I also present student feedback for Human Physiology Online from anonymous course surveys.