fundamentals
Cells
Function of cells
Some cells, especially glandular cells, have as their primary function the production of complex substances, such as a hormone or an enzyme. Hormones are chemical messengers that control and coordinate activities throughout the body. For example,insulinis a hormone produced by certain cells in the pancreas to help regulate blood sugar levels. Enzymes are complex proteins that control and carry out nearly all chemical processes and reactions within the body. Other cells in the pancreas produce digestive enzymes that break down food so that it can be absorbed. Some cells produce other useful substances such as cells in the breast that produce milk, cells in the lining of the lungs that produce mucus, and cells in the mouth that produce saliva. Other cells have primary functions that are not related to the production of substances. For example, muscle cells contract, allowing movement. Nerve cells generate and conduct electrical impulses, allowing communication between the central nervous system (brain and spinal cord) and the rest of the body. 