When there is no coroner or deputy coroner in a county in which the office of coroner has not been replaced by a county medical examiner or when both are absent from the county when needed or will not or cannot perform the duties required under this article, the medical examiner shall assume the duties and responsibilities of the coroner. When the medical examiner is performing the duties of the coroner in such cases, such medical examiner may sign the death certificate except when an inquest is held.