Doctor Who is a Time Lord, from the planet Gallifrey
Although he physically resembles a human, as a Time Lord his physiology is different.
Like other members of his race, he has two hearts, he can go without breathing for a period of time, and has greater strength and stamina than humans.
When a Time Lord suffers a mortal injury, illness, or old age, they have the ability to regenerate which give them extremely long life spans.
"I'm a Time Lord"
"Thats what my race is called"
1. A contemptible person, possibly with ultimate control over time and space.
2. A desirable person of either gender, again, possibly with ultimate control over time and space.
1. Begone, you vile Time Lord!
2. Goodness, that maiden appears to be quite the Time Lord