Welcome to Crash Course Anatomy & Physiology! -- Pssst... we made flashcards to help you review the content in this episode! Find them on the free Crash Course App! Download it here for Apple Devices: https://apple.co/3d4eyZo Download it here for Android Devices: https://bit.ly/2SrDulJ -- Crash Course is on Patreon! You can support us directly by signing up at http://www.patreon.com/crashcourse Want to find Crash Course elsewhere on the internet? Facebook - http://www.facebook.com/YouTubeCrashCourse Twitter - http://www.twitter.com/TheCrashCourse Instagram - https://www.instagram.com/thecrashcourse/ CC Kids: null