Cork and cork cambium (cork producing cell layer) are external Cortex-this is the primary tissue of the plant stem Phloem & Xylem are the inner most part and are concerned with carrying fluid and nutrients up and down the plant. Source(s): http://en.wikipedia.org/wiki/Bark. Orinoco Â· 9 years ago.
Malocclusion and bruxism are the most common causes of TMJ disorders. 1  Emotional stress is often the underlying cause of a TMJ disorder, as it can contribute to people either consciously or unconsciously tightening facial and jaw muscles and grinding or clenching their teeth.
Common Causes of TMJ Disorder. Temporomandibular joint (TMJ) and myofascial pain dysfunction (MPD) may be caused by: Trauma to the head or neck, e.g. whiplash. Pathology or trauma to the joint itself, e.g. arthritis. Hormonal imbalances, e.g.. growth spurts in teens, menstrual cycle and menopause in women.