Give scientific reasons:
$(1)$ The pancreas is an exocrine as well as an endocrine gland.
$(2)$ The liver,although not taking part in the process of digestion directly,is an important accessory digestive gland.

(N/A) $(1)$ The Islets of Langerhans located in the pancreas secrete hormones like Glucagon and Insulin. These hormones are transported by the blood to their target organs,making it a ductless endocrine gland. Simultaneously,the pancreas secretes pancreatic juice containing various digestive enzymes,which is transported to the duodenum via the pancreatic duct. Thus,it functions as an exocrine gland.
$(2)$ The liver secretes bile juice,which contains inorganic salts like $Na_{2}CO_{3}$ and $NaHCO_{3}$. These salts provide an alkaline medium in the duodenum,which is essential for the activation of pancreatic enzymes. Additionally,bile juice contains organic salts like sodium taurocholate and sodium glycocholate,which help in the emulsification and digestion of fats. Therefore,although the liver does not secrete digestive enzymes,it plays a crucial role in digestion,making it an important accessory digestive gland.