[annabananapi]

If you don't have many team members, a single captain (over the entire team) would most likely suffice. I don't know how long your team has been functioning, but if one student stands out as the most passionate and dedicated to the team's objectives, they would probably be a good choice for a leadership role.
On my team, we have two co-captains (one for fabrication and one for marketing) who work closely together, and then six department captains. Each co-captain is in charge of three departments, but they are not necessarily experts in all of them. Our team is 40 members, so this specific structure is probably a little more complex that what you are looking for. But the basic structure of captain(s) may be helpful.
Any captain(s) should be in contact with each other and everyone on the team. That way, they know who is coming to meetings and who isn't. Structure is for efficiency.