The valves regulate fluid flow to the second chamber in accordance with {HEAD ~ electrical signals} from {TAIL ~ the heart} 
from
The valves regulate fluid flow to the second chamber in accordance with { HEAD ~ electrical signals } from { TAIL ~ the heart }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL