He asked: 'Who are the Rudras?' Yagnavalkya replied: 'These ten vital breaths (pranas, the senses, i.e. the five gnanendriyas, and the five karmendriyas), and Atman, as the eleventh. When they depart from this mortal body, they make us cry (rodayanti), and because they make us cry, they are called Rudras.'

In plain words: Yagnavalkya says the Rudras are the ten life-powers of the body: the five senses and the five powers of action, with the self as the eleventh. When they leave the body at death, they make the living cry. The word Rudra comes from "to make cry."