which organ is found in the left, upper quadrant of the abdomen and secretes digestive enzymes, insulin, and glucagon

This organ is the pancreas. It is a very small endocrine gland measuring 6 inches that is located on the left abdomen near the duodenum of the small intestine and the spleen. The pancreas is a very important organ that secretes digestive enzymes like:

pancreatic amylase - breaks down polysaccarides and glycogen into simple sugars
trypsin- breaks down proteins into amino acids
pancreatic lipase - breaks down triglycerides to fatty acids and monoglycerides
ribonuclease - digests nucleic acids

It also secretes insulin and glucagon to regulate blood sugar levels.