Name the four hormones secreted by the duodenal epithelium as the food enters the duodenum

Cholecystokinin – It is responsible for contraction and relaxation of gall bladder to release bile into the stomach in order to digest the fat and protein present in the food.  

Duocrinin – It is responsible for stimulation of Burner’s gland to secrete enzymes and mucus to help indigestion.

Enterogastrone – It is involved in inhibition of gastric secretion when the condition is unfavorable.

Secretin- When the acidic content of the empty stomach reaches the duodenum, this hormone is secreted.

Explanation:

these muscles maintain the blood pressure in the vessels. the smooth muscles are innervated by nerves of the autonomic nervous system. when the muscles contract, they cause vasoconstriction of the vessels and increase blood pressure. when the muscles relax, they enable vasodilation of the   blood vessels hence reduce blood pressure.