Human Digestive System - Free MCQ Practice Test with solutions, UPSC Lucent

Pancreatic lipase assists at the beginning of fat digestion in the duodenum, but due to its tiny size, it cannot be finished there.
Furthermore, the small intestine is a part of it. In babies, the stomach is where some digestion takes place.

• In the digestion of animals, proteins are broken down into amino acids.
• Food deterioration is facilitated by amino acids.
• The building blocks of life are amino acids.
• Tyrosine, Tyrosine, and Glutamine are a few examples of amino acids.
• Oil and fats are both components of lipid molecules.
• The body uses sugar as a source of energy.

There are 5 phases in the digestive process, which go in the following order: Ingestion, Digestion, Absorption, Assimilation, Egestion

• Ingestion: It is the process through which an animal takes food into its body.
• Digestion: It is the process by which food consists of larger molecules and is transformed and broken down into small water-soluble molecules. 
• Absorption: It is the process by which digested food enters the bloodstream. 
• Assimilation: It is the process by which ingested food is absorbed by the body’s cells for use as fuel and a source of growth.
• Egestion: It is the process in which Undigested food is expelled as faeces

• Vitamin Niacin is a water-soluble vitamin necessary in regular metabolism as it is a source of coenzyme “Nicotinamide Adenine Dinucleotide (NAD)”  and “Nicotinamide Adenine Dinucleotide Phosphate (NADP)”. 
• Vitamin Niacin is another name for vitamin B3 or nicotinic acid.
• The deficiency of nicotinic acid causes Pellagra and canine(dog) disease (black tongue). 
• Pellagra traits by scaly, pigmented skin, and irritation of the GI tract.

• Rennin is a proteolytic enzyme present in the gastric juice in the stomach of infants which aids in the digestion of Casein (milk protein). 
• Rennin is produced by the main cells and is also referred to as chymosin.
• Its help in digestion is to curdle or coagulate milk in the stomach, which is crucial for young animals.
• Rennin secretions are at their highest in the first few days after birth, then they start to fall, and then pepsin takes their place.
• Rennin is released as an inactive proenzyme that is known as prochymosin and becomes active when it comes into contact with an acidic media.

• A starch hydrolyzing enzyme called diastase converts complex carbs into simple ones.
• It promotes digestion in situations of chronic illness, stomach fullness, flatulence, and indigestion.
• Diastase is an enzyme that helps turn starch into maltose.
• Diastase enzymes are secreted in the oral cavity (mouth).

• The largest gland in the body is the liver.
• Bile juice, which is kept in the gall bladder, is secreted by the liver.
• A shared duct allows for the flow of both pancreatic and bile juice into the small intestine.
• The liver stores glycogen, which is unutilized glucose.
• The liver produces bile juice, urea, and heparin.
• 75 percent of the blood that the liver receives comes via the portal veins, with the remaining 25 percent coming from the hepatic artery. Life is known to have a dual blood supply because of this.

• Ninety percent of the digestion and absorption of food takes place in the small intestine, with the remaining ten percent happening in the stomach and large intestine.
• The majority of digestion and nutrient absorption takes place in the small intestine.
• There are millions of tiny finger-like projections lining in the small intestine called villi.

• The large intestine plays important role in our digestive system; it can absorb most of the water from Indigested food. 
• The large intestine moves primarily in three different ways: peristalsis, mass peristalsis, and haustral churning.
• The substance travels through the colon’s ascending, transverse, descending, and sigmoid segments before entering the rectum.
• The waste is eliminated from the body through the rectum.
• The length of the large intestine is roughly five feet (or 1.5 meters).

• The enzyme pepsin digests proteins. 
• Protein is the basic molecule in the human body.
• The proenzyme pepsinogen that is in contact with hydrochloric acid gets transformed into the active enzyme pepsin.
• Pepsin transformed proteins into peptones.

• The islets of Langerhans in the pancreas contain several types of endocrine cells: α (alpha), β (beta), δ (delta) and γ (gamma) cells.
• β (beta) cells secrete insulin. Insulin lowers blood glucose by promoting the uptake of glucose into body cells and by stimulating glycogen synthesis in the liver.
• α (alpha) cells secrete glucagon; δ (delta) cells secrete somatostatin; γ (gamma) cells (also called PP cells) secrete pancreatic polypeptide.

Hence, the correct answer is Option B.

• A peptide hormone of the digestive tract is cholecystokinin. It aids in promoting the breakdown of protein and fat.
• It is produced by a cell in the small intestine’s epithelium, and it is secreted in the duodenum.
• triggers the gallbladder to secrete bile and pancreatic juice.

• Saliva is a liquid that various animals, including humans, create in their mouths that is typically frothy. 
• Saliva is 98 percent water and is produced in salivary glands, but it also contains numerous essential elements like electrolytes, mucus, antibiotic chemicals, and other enzymes.
• Saliva performs a variety of digestive tasks, including moistening food and assisting in the formation of a bolus of food that is simple to swallow.
• The amylase enzyme, which converts certain starches into maltose and dextrin, is found in saliva.
• As a result, food is already being digested in the mouth before it even reaches the stomach.
• Saliva does not break down fats, fibers, or proteins.

• The polysaccharide is produced and then stored as glycogen in the liver. Glycogen is transformed into glucose when the body needs energy, and then glucose is released into the blood to reach the target cell.
• A multibranched polymer of glucose is called glycogen.
• In both humans and animals, glucose is stored as glycogen.
• Mostly in the liver and muscles, glycogen is created and stored.
• The process of glycogenesis transforms any glucose that is not immediately consumed into glycogen for storage in the liver and muscles.

• Cirrhosis is a late stage of liver scarring (fibrosis) brought on by a number of disorders and diseases affecting the liver, including hepatitis and chronic drinking.
• The liver is unable to carry out its essential tasks of metabolism, and protein synthesis, including the creation of blood clotting factors, and drug and toxin filtering.

• The parotid gland, submaxillary gland, sublingual gland, and infra-orbital gland are the four pairs of salivary glands found in rabbits.
• Humans do not have an infraorbital gland.

Hydrolytic enzymes disassembled protein, lipids, nucleic acids, carbohydrates, and fat molecules into their most basic components.
Mostly all digestive enzymes are hydrolytic enzymes.
Due to the release of HCl, the pH of the stomach is low. Protease, a protein-digesting enzyme, operates in low pH environments, such as the stomach.
Amylase is a starch (carbohydrate) digesting enzyme that’s why carbohydrate digestion does not take place in the stomach.
The dehydrogenation (oxidation) of numerous compounds in the presence of hydrogen peroxide is catalyzed by peroxidase, an iron-containing enzyme that is primarily found in plants but is also present in leucocytes and milk.

The stomach is a muscular J- shaped thickly walled bag-like structure that is one function that stores the food for several hours by a sphincter called the gastro-esophageal sphincter. 
It is divided into four portions that are Fundus, Cardiac, Body, and Pyloric regions. 
The pylorus is a narrow cone-shaped constriction placed at the end of the stomach and the starting of the small intestine. 
It consists of two sections antrum which combines the parts of the stomach and the pyloric canal and also joins the stomach and small intestine.
The pyloric region opens into the small intestine through the Pyloric sphincter.

The pancreas is a part of the digestive system that is placed in the abdomen beyond the stomach and performs as a gland. 
The pancreas serves both endocrine as well as exocrine functions. 
As an endocrine gland, it assists in the secretion of hormones like glucagon and insulin and regulates blood sugar levels.
Additionally, it performs the role of an exocrine gland, secreting pancreatic juice by the pancreatic duct into the duodenum.

• The small intestine is the longest component of the digestive system.
• The length of the small intestine is 7 meters (22 feet).
• The small intestine’s primary activities are to absorb nutrients and finish food digestion.