Step-by-step explanation:
Acinar cells that secrete enzymes or bicarbonates in the small intestine which are necessary for nutrient digestion. Digestive enzymes are activated only once they have reached the duodenum.
Islet cells that secrete insulin or glucagon within the pancreas is a type of Beta cell. Insulin or glucagon are both secreted in response to blood sugar level.
Blood vessels tubular structures in the circulatory system that carries blood throughout the body. The most important types are arteries and veins.