In the labelled part A(i.e., the stomach,) the enzyme responsible for first stage of protein digestion is produced.A-stomac, B-pancrease,C-small intestine,D-gall bladder.

The local digestive hormones are produced by gastric and intestinal mucosa e.g., secretin, cholesyctokinine, etc. The hormones stimulate the activity of enzymes. If these are not produced, the process of digestion will be hindered and digestive system will not work properly.

If goblet cells are non-functional for some reason, this will adversely affect smooth movement of food down the intestine due to the absence of much.
These glands secrete mucus which along with succus entericus which helps in digestion and movement of food material in the alimentary canal.

Stomach, serves as a right place due to the following reasons
(i) HCl inactivates the salivary amylase and prevents further breakdown of disaccharide carbohydrate.
(ii) It kills microorganisms and lower the pH of stomach between 1.2.5 (very acidic).
(iii) Pepsinogen (inactive precursor of pepsin) in the presence of HCl is converted into pepsin (principal protease of stomach).

If the liver would stop secreting the bile,following may happen
(i) The fats in our diet would not digested, it is because bile helps in emulsiying fats and breaks it down for the body to absorb
(ii) The liver makes bile from chlesterol.Thus,higher levels of cholesterol in the body may occur.
(iii) Bilirubin is made from our dead red blood cells and is a type of a pigment , that also acts as a part of the bile.Hence, if the liver does not secrete bile, the bilirubin would stay in blood instead of being converted by the liver into soluble form and flows with the bile.
(iv) This may our skin,white of the wyes more yellow in color(jaundice),darken our urine and the stools would be whiter in color.