As control signal 47 is active high, transistor 36 is turned on to apply {TAIL ~ voltage} at {HEAD ~ node} 38 to node 39 
As control signal 47 is active high , transistor 36 is turned on to apply { TAIL ~ voltage } at { HEAD ~ node } 38 to node 39
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH