Suturing devices and systems used to apply sutures and/or to close openings at, within, or into a biological structure. The suturing device can comprise an elongate member having a proximal end, a distal end, one or more distal arms, one or more proximal extensions, and one or more needles. A sheath may be used with the device to maintain or substantially maintain haemostasis while the device is used and while a procedure is performed in the biological structure.