Because many other body systems, including the vascular, nervous, and integumentary systems, are interrelated, disorders of one of these systems may also affect the musculoskeletal system and complicate the diagnosis of the disorder's origin. Diseases of the musculoskeletal system mostly encompass functional disorders or motion discrepancies; the level of impairment depends specifically on the problem and its severity. Articular diseases (of/or pertaining to the joints) are the most common. Some diseases and disorders may adversely affect the function and overall effectiveness of the system. Disorders of muscles from another body system can cause irregularities such as impairment of ocular motion and control, respiratory dysfunction, or bladder malfunction. Complete paralysis, paresis, or ataxia may be caused by primary muscular dysfunctions of infectious or toxic origin; however, the primary disorder is usually related to the nervous system, with the muscular system acting as the effector organ capable of responding to a stimulus, especially a nerve impulse.