1570s, "action of pouring liquid from one vessel to another," from French transfusion and directly from Latin transfusionem (nominative transfusio) "a decanting, intermingling," noun of action from past-participle stem of transfundere "pour from one container to another," from trans "across, beyond" (see trans-) + fundere "to pour" (from nasalized form of PIE root *gheu- "to pour"). Sense of "transfering of blood from one individual to another" first recorded 1640s.
"to beat or throb (as the heart or a blood vessel); contract and dilate in alternation or rhythmically," 1741, a back-formation from pulsation, or else from Latin pulsatus, past participle of pulsare "to beat against, strike upon," frequentative of pellere (past participle pulsus) "to beat, strike" (from PIE root *pel- (5) "to thrust, strike, drive"). Related: Pulsated; pulsating; pulsatile.
early 15c., "bloodshot," from Late Latin sanguinosus "full of blood," from Latin sanguis "blood" (see sanguinary). Meaning "pertaining to blood" is from 1813.