Accountability, responsibility, and expectations are closely linked.
In setting sharp expectations, you are articulating areas of responsibility.
Then, for not living up to that responsibility, you might be held to account.
When expectations are fuzzy, responsibility is also fuzzy, and so holding people to account is difficult.
Expectations: build a hut – two metres tall, three metres wide, by next week.
Responsibility: by next week, a hut that is two metres tall and three metres wide.
Accountability: you will answer for any deficiency in the hut, as defined above.