a narrow opening produced by cleavage or separation of parts. 2. cleavage (def 1). 3. Anatomy. a natural division or groove in an organ, as in the brain. verb (used with object), fissured, fissuring. 4. to make fissures in; cleave; split.
A diet rich in potassium helps to counterbalance some of sodium's harmful effects on blood pressure. Foods that are good sources of potassium are listed in the Food Sources of Potassium table on the next page.
This includes when it occurs and how fast it occurs. The retinoic acid form of Vitamin A helps to regulate the rate of gene transcription. Vitamin A Supports the Immune System. The skin and the lining that covers the digestive, respiratory and urinary tracts are important components of the immune system. They are your body's first barrier against infection.