The pH of the stomach is important in regulating the physiological processes involved with breaking down food. When the pH is too low, this creates an acidic environment in the stomach that kills bacteria. As pH decreases, pepsin becomes more active in disassembling proteins into smaller peptide chains, which is useful in breaking down tissue and plant cell walls into usable nutrients.
The digestive system is important in the breakdown of food into ions, vitamins, and fluids that are necessary by the body's cells for proper functioning of other systems. The digestive system has several factors that regulate its activity, which include hormonal, neural, and local mechanisms.
Hormonal mechanisms include the release of CCK in response to high fat meals, which is necessary to produce sufficient pancreatic enzymes. Neural mechanisms can refer to parasympathetic motor center's stimulation of the release of gastric juices and secretions. This occurs to help initiate the stomach's churning and mixture of food with digestive juices. Local mechanisms can include the pyloric sphincter's regulation of chyme flow from the stomach to the small intestine.
Thus, the correct answer is (d).
Choices (a) through (c) are incorrect because all of the listed choices, not just one, contribute to control of the digestive activities.
The pyloric sphincter is a muscular band that is positioned between the small intestine and stomach. This structure is located distally from the stomach and extends from the pylorus. The pyloric sphincter's main responsibility is to regulate the flow of chyme between the stomach and small intestine. Thus, the correct answer is (c).
Liver cells are otherwise called hepatocytes. They are arranged as series of irregular plates resembling the spokes of a wheel. Hence, the correct match is (k) hepatocytes.
Intrinsic factor is a protein that aids our body in the absorption of vitamin B12. Vitamin B12 is essential for the formation and growth of red blood cells. Hence, the correct match is (g).
Mesentery is a double layered serous membrane sheet suspending the jejunum and ileum from the posterior wall of the abdomen. Therefore, the correct match is (a).
The chief cells are also called gastric zymogenic cells or peptic cells. They are present in the stomach and release pepsinogen. Hence, the correct match is (i).
Palate is the roof of the oral cavity or mouth. It is seen in all mammals including humans. The main role of it is to separate the oral cavity from the nasal cavity.
Hence, the correct match is (h).
Parietal cells are also called oxyntic cells or delomorphous cells. They are a kind of stomach epithelial cells. Their role is to secrete gastric acid that is hydrochloric acid and intrinsic factor. Hence, the correct match is (j).
Parasympathetic system controls external organs like digestive organs. For example, the parasympathetic stimulation increases the muscular activity of the digestive system.
Hence, the correct match is (d).
Sympathetic actions and parasympathetic actions are opposite to each other. For example, sympathetic stimulation inhibits the muscular activity of digestive tract. Hence, the correct match is (f).
Peristalsis is a kind of movement that aids in the movement of materials along the digestive tract. Therefore, the correct match is (b).
Bile salts are released from the gall bladder. They are used for the emulsification of fats. Therefore, the correct match is (l).
Salivary amylase is an enzyme present in the saliva of mammals including humans. It catalyzes the hydrolysis of starch. It breaks down the starch into sugars. Hence, the correct match is (e).