The attached video tells you about Opioids that are centrally acting analgesics that can produce inhibitory response on CNS as well as on the respiratory system . The video covers all the basic topics under the heading in a simple manner. Timeline: 0:21:opioids 3:46:nociceptive neurons 7:05:GI smooth muscle 7:48:respiratory system 8:53:other smooth muscle 9:11:mast cells 9:59:occulomotor nerve 10:47:gall bladder 11:49:chemoreceptor trigger zone 12:42:side effects