Pain behind one eye is a common complaint among people who suffer with cluster headaches and the one-sided nature does not usually change sides. Eyestrain is one of the common causes of pain behind the eyes and it is prevalent these days with prolonged use of computers and long hours of watching TV. It is due to multiple factors like dry eyes from infrequent blinking and strain of the inner eye muscles due to staring at a fixed distance for a long period of time.
Because these somatic cells do not regularly use telomerase, they age. The result of aging cells is an aging body. If telomerase is activated in a cell, the cell will continue to grow and divide. This immortal cell theory is important in two areas of research: aging and cancer. Cellular aging, or senescence, is the process by which a cell becomes old and dies.
Here, an enzyme called enterokinase is released from the brush-border villi. Now, the activated trypsin goes on to activate all other released enzymes like the chymotrypsinogen, procarboxypeptidase, etc. into their active forms of chymotrypsin and carboxypeptidase, etc. Trypsin and chymotrypsin are both protein digesting enzymes. They break down proteins into their component amino acids.