External functional device, which has: at least one body of the housing, at least one chamber (9, 15, 21, 57) integrated in the body of the housing, to accommodate medical fluids； at least one channel (17, 19, 49) integrated in the housing body, to accommodate and / or guide a medical fluid； and at least one valve device (35, 36, 39, 40, 47, 51, 53, 61) fully or partially integrated in the housing body, to control or regulate a fluid circulating through the functional device external, where the external functional device, at least on one of its surfaces, is provided with a coating device that is part of at least one valve device (35, 36, 39, 40, 47, 51, 53, 61) integrated, and where the coating device, at least in one section, is attached in a non-positive, positive and / or by adhesion of materials to the housing body, where the external functional device is designed as a cassette (1000) for a blood treatment, and where the external functional device has at least one venous blood chamber (21), where at least one valve device has a blood valve of a needle (61) that is disposed between the chamber of venous blood (21) and a A needle chamber (57) of the external functional device, which, referred to the alignment of the external functional device during use, is disposed above the venous blood chamber (21).Dispositivo funcional externo, el cual presenta: al menos un cuerpo de la carcasa, al menos una cámara (9, 15, 21, 57) integrada en el cuerpo de la carcasa, para alojar fluidos médicos； al menos un canal (17, 19, 49) integrado en el cuerpo de la carcasa, para alojar y/o guiar un fluido médico； y al menos un dispositivo de válvula (35, 36, 39, 40, 47, 51, 53, 61) integrado completamente o de forma parcial en el cuerpo de la carcasa, para controlar o regular un fluido que circula a través del dispositivo funcional externo, donde el dispositivo funcional externo, al menos en una de sus superficies, está provisto de un dispositivo de recubrimiento que forma parte de al m
