(2) Mineralocorticoids. Mineralocorticoids keep mineral salt metabolism in
balance which, in turn, helps to maintain the body's electrolyte and fluid intracellulary
balance. Aldosterone, a mineralocorticoid, regulates the metabolism of sodium,
chloride, and potassium. Aldosterone causes sodium to be absorbed into the blood
which leads to water being reabsorbed in the farthest renal tubules. Proper levels of
aldosterone also cause potassium to be excreted and aids in the maintenance of normal
(1) Functions. The pancreas is a gland with two major functions, one an
endocrine function and the other an exocrine function. As an endocrine organ, the
pancreas produces the hormone insulin. As an exocrine organ, the pancreas produces
a variety of enzymes (protein-digesting enzymes, fat-digesting enzymes, and
(2) Composition. The pancreas, located slightly behind and toward the top
of the stomach, is composed of three parts: a head, body, and tail. The average length
is about six inches, and the average weight is about three ounces. The endocrine
portion of the pancreas is called the isles of Langerhans which are clusters of cells.
Three kinds of cells are found here: alpha cells, beta cells, and delta cells.
Figure 1-5. The pancreas.
b. Hormones. Alpha cells secrete the hormone glucagon which acts primarily
on the liver. Alpha cells increase the body's blood sugar level by causing sugar to be
removed from storage in the liver and transferred to the blood. Beta cells secrete
insulin which affects most body cells. Insulin causes a decrease in blood sugar by
increasing the ability for body cells to take up and use sugar. Beta cells promote
storage of sugars and fats on body tissue and promote building of body protein. Delta
cells secrete somatostatin, a hormone which inhibits growth.