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.
TMJ disorders â a type of temporomandibular disorder or TMD â can cause pain in your jaw joint and in the muscles that control jaw movement. The exact cause of a person's TMJ disorder is often difficult to determine. Your pain may be due to a combination of factors, such as genetics, arthritis or jaw injury.