Nurse Christine Chapel (Voice by Majel Barrett).
On stardate 5483.7, while under the influence of the women of Taurus II, the male crewmembers of the Enterprise were incapacitated enough by the "siren's song" to nessecitate that Lieutenant Uhura assume command of the ship. Uhura assigned Chapel as acting Chief Medical Officer. She and Uhura then led an all-woman landing party that beamed down to Taurus II to rescue Kirk, Spock, and Dr. McCoy. ("The Lorelei Signal") In 2369, Christine Chapel obtained a love potion from Harry Mudd and she used it on Spock. For a time he was in love with her but the effects of the drug were only temporary. ("Mudd's Passion") While in a miniaturized state, Nurse Chapel assisted Dr. McCoy mend Mr. Sulu's broken leg. ("The Terratin Incident") After Captain Kirk and Mr. Spock were mutated into water breathers on stardate 5499.9, Nurse Chapel assisted Dr. McCoy when he reversed their mutations.("The Ambergris Element")
Although the character of Nurse Chapel appeared in only five episodes of the animated series: "The Survivor", "The Lorelei Signal", "Mudd's Passion", "The Terratin Incident" and "The Ambergris Element", she was the main focus in "Mudd's Passion". Majel Barrett portrayed Nurse Chapel in the live action Star Trek series as well, and she also provided the voices for several other characters in the Animated Star Trek series including Lieutenant M'Ress and the voice of the ship's computer.