A cannula system for conveying a liquid, in particular blood, is provided comprising: a cannula with a tube element having a front end region and a rear end region, wherein a channel extends through the tube element from the front end region of the tube element to the rear end region of the tube element； a hollow body, wherein the hollow body has a front end region that can be inserted into the channel of the tube element through a front inlet opening of the channel； and a connector which is designed to receive the front end region of the tube element and the front end region of the hollow body in an internal region of the connector when the cannula system is in a connection state, in which the front end region of the tube element is inserted into the channel of the tube element of the cannula.
