Human Digestive System Practice Questions
20 free Human Digestive System practice questions for the NCERT Biology. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
Which of the following terms describes the human dentition based on the fact that teeth are embedded in sockets of the jaw bone?
- A Pleurodont
- B Thecodont type
- C Diphyodont
- D Heterodont
Correct answer: Thecodont type
Human teeth are called thecodont because each tooth is embedded in a socket of the alveolar bone. This provides strong structural support for mastication.
The hard chewing surface of the teeth, which helps in the mastication of food, is made up of:
- A Dentine
- B Pulp
- C Enamel
- D Cementum
Correct answer: Enamel
Enamel is the hardest substance in the human body and covers the crown of the tooth. It is highly mineralized and designed to withstand the mechanical stress of chewing.
What is the dental formula of an adult human?
- A 2102/2102
- B 2123/2123
- C 2122/2122
- D 2133/2133
Correct answer: 2123/2123
The adult human dental formula 2123/2123 represents two incisors, one canine, two premolars, and three molars in each half of the upper and lower jaws. This totals 32 permanent teeth.
Which structure prevents the entry of food into the glottis during swallowing?
- A Sphincter of Oddi
- B Gastro-oesophageal sphincter
- C Epiglottis (cartilaginous flap)
- D Pyloric sphincter
Correct answer: Epiglottis (cartilaginous flap)
The epiglottis is a cartilaginous flap that covers the glottis (opening of the windpipe) during deglutition. This reflex action ensures food enters the esophagus rather than the larynx.
The stomach is anatomically divided into four main parts. Which part opens into the first part of the small intestine?
- A Fundus
- B Cardiac
- C Body
- D Pyloric
Correct answer: Pyloric
The pyloric portion is the terminal part of the stomach that leads into the duodenum. The flow of food through this junction is regulated by the pyloric sphincter.
Which of the following is the correct sequence of the three parts of the small intestine?
- A Duodenum -> Ileum -> Jejunum
- B Jejunum -> Duodenum -> Ileum
- C Duodenum -> Jejunum -> Ileum
- D Ileum -> Jejunum -> Duodenum
Correct answer: Duodenum -> Jejunum -> Ileum
The small intestine starts with the C-shaped duodenum, followed by the long coiled middle portion called the jejunum, and ends with the highly coiled ileum.
The opening of the stomach into the esophagus is regulated by which muscular sphincter?
- A Pyloric sphincter
- B Sphincter of Oddi
- C Lower esophageal sphincter
- D Ileocaecal sphincter
Correct answer: Lower esophageal sphincter
The lower esophageal sphincter (also called the cardiac or gastro-oesophageal sphincter) controls the passage of food from the esophagus into the stomach. It also prevents the backflow of acidic gastric contents into the esophagus.
Which layer of the alimentary canal wall forms irregular folds called rugae in the stomach?
- A Serosal layer
- B Muscular layer
- C Sub-mucosal layer
- D Mucosa
Correct answer: Mucosa
The mucosa is the innermost layer of the alimentary canal. In the stomach, it forms thick longitudinal folds called rugae that allow the stomach to expand when food is ingested.
The 'Crypts of Lieberkuhn' are found in which layer of the intestinal wall?
- A Serosal layer
- B Muscular layer
- C Sub-mucosal layer
- D Mucosa
Correct answer: Mucosa
Crypts of Lieberkuhn are tubular glands located in the mucosal layer between the bases of the villi in the small intestine. They secrete succus entericus, which contains various digestive enzymes.
Which of the following is the largest gland of the human body?
- A Pancreas
- B The liver
- C Salivary glands
- D Adrenal glands
Correct answer: The liver
The liver is the largest gland in the human body, weighing approximately 1.2 to 1.5 kg in an adult. It is situated in the abdominal cavity just below the diaphragm.
The hepatic lobules are covered by a thin connective tissue sheath called:
- A Bowman's capsule
- B Glisson's capsule
- C Peritoneal capsule
- D Pericardial sac
Correct answer: Glisson's capsule
Glisson's capsule is a thin connective tissue sheath that is characteristic of the mammalian liver. It wraps around each hepatic lobule, which is the structural and functional unit of the liver.
The duct of the gallbladder along with the hepatic duct from the liver forms the:
- A Pancreatic duct
- B Common bile duct
- C Hepatopancreatic duct
- D Cystic duct
Correct answer: Common bile duct
The cystic duct from the gallbladder joins the common hepatic duct to form the common bile duct. This duct then carries bile toward the duodenum.
Which sphincter regulates the opening of the common hepatopancreatic duct into the duodenum?
- A Pyloric sphincter
- B Sphincter of Oddi
- C Anal sphincter
- D Cardiac sphincter
Correct answer: Sphincter of Oddi
The Sphincter of Oddi is a muscular valve that controls the flow of digestive juices (bile and pancreatic juice) into the second part of the duodenum. It prevents reflux of duodenal contents into the ducts.
Brunner's glands, which help in neutralizing gastric acid, are located in the:
- A Mucosa of the stomach
- B Sub-mucosa of the duodenum
- C Mucosa of the esophagus
- D Sub-mucosa of the colon
Correct answer: Sub-mucosa of the duodenum
Brunner's glands are unique to the sub-mucosal layer of the duodenum. They secrete an alkaline mucus that protects the intestinal wall from the highly acidic chyme arriving from the stomach.
The structural and functional units of the liver are called:
- A Hepatocytes
- B Hepatic lobules
- C Hepatic sinusoids
- D Kupffer cells
Correct answer: Hepatic lobules
Hepatic lobules are the structural and functional units of the liver. Each lobule contains cords of hepatocytes arranged around a central vein.
Which part of the large intestine is a blind sac and hosts some symbiotic micro-organisms?
- A Gastric mucosa
- B Duodenal sub-mucosa
- C Oesophageal mucosa
- D Colonic sub-mucosa
Correct answer: Duodenal sub-mucosa
Brunner's glands are unique to the sub-mucosal layer of the duodenum. They secrete an alkaline mucus that protects the intestinal wall from the highly acidic chyme arriving from the stomach.
The vermiform appendix, a vestigial organ, arises from which part of the alimentary canal?
- A Duodenum
- B Caecum
- C Jejunum
- D Ileum
Correct answer: Caecum
The vermiform appendix is a narrow, finger-like tubular projection that arises from the caecum. In humans, it is considered vestigial, although it may play a minor role in the immune system.
Which layer of the alimentary canal contains nerves, blood vessels, and lymph vessels?
- A Outer serosa
- B Sub-mucosa
- C Muscularis externa
- D Mucosa
Correct answer: Sub-mucosa
The sub-mucosa is a layer of loose connective tissue that supports the mucosa. It contains larger blood vessels, lymphatics, and nerve plexuses such as Meissner's plexus.
The pancreas is a compound gland (heterocrine). The exocrine portion secretes:
- A Insulin and glucagon
- B Bile and mucus
- C Pancreatic juice with enzymes
- D Succus entericus
Correct answer: Pancreatic juice with enzymes
The exocrine part of the pancreas consists of acini that secrete pancreatic juice into the duodenum. This juice contains digestive enzymes like trypsinogen, chymotrypsinogen, amylase, lipase, and nuclease.
Which of the following is NOT a salivary gland in humans?
- A Parotid
- B Sub-maxillary
- C Sub-lingual
- D Lacrimal
Correct answer: Lacrimal
The three pairs of salivary glands are the parotids (cheek), sub-maxillary/sub-mandibular (lower jaw), and sub-linguals (below the tongue). Lacrimal glands are tear glands and are not part of the digestive system.