The Gerousia was the Spartansenate. Meaning Council of Elders it consisted of thirty members including the two kings. Members had to be over the age of 60 and were elected for life. Theoretically, any Spartan citizen of the right age could stand but in practice members were selected from the most important aristocratic families.
The Gerousia prepared motions or rhetrai for the wider citizen assembly, the Apella, to vote on. The Gerousia could also veto motions passed by the Apella and was consulted by the ephors in matters of interpretation of the law.
The presiding officers were at first the kings, but in historical times the ephors, and the voting was conducted by shouts; if the president was doubtful as to the majority of voices, a division was taken and the votes were counted.
The apella was responsible for electing men to the gerousia for life.
Moreover, the gerousia always had the power to veto the decision of the apella.