Biology, HSSC-Punjab First Year. This chapter is split into 23 topics and has
545 practice questions. The topics covered are listed below, followed by
10 free sample questions from the chapter.
Topics in this chapter
The large intestine, water absorption and egestion25 questions
The oral cavity: teeth, tongue and salivary glands25 questions
Pancreas and hormonal control of secretions25 questions
Swallowing and the pharynx25 questions
Oesophagus, peristalsis and antiperistalsis25 questions
Digestive system overview and alimentary canal25 questions
Absorption of digested food25 questions
Chapter review: digestive system (end-of-chapter exercise focus)25 questions
The stomach: structure and gastric glands25 questions
Liver, gallbladder and bile25 questions
Gastric juice and its regulation25 questions
The small intestine and digestive enzymes25 questions
Chapter 9 learning outcomes and overview of digestion25 questions
Figures 9.1 to 9.5: labels and what they show21 questions
Stomach structure and Figure 9.6: further detail20 questions
Pancreas: exocrine and endocrine portions and pancreatic enzymes21 questions
Liver, bile and Figure 9.8: further detail20 questions
Digestive system numbers: lengths, pH values and counts20 questions
Intestinal wall, villi, large intestine and egestion: further detail20 questions
Oral cavity, swallowing and motility: further detail and scenarios20 questions
Chapter 9 exercise: question numbers and prompts24 questions
Digestive enzymes, hormones and meal-based reasoning29 questions
Digestive system: statement analysis and organ-function matching25 questions
Sample questions: Human Digestive System
10 sample questions with the correct answer and an explanation. Try to answer each one before reading the explanation.
Q1. According to Figure 9.8, which sequence correctly traces the ducts through which bile flows from the liver to the duodenum?
A. Common hepatic duct -> cystic duct -> pancreatic duct -> duodenum
B. Right and left hepatic ducts -> pancreatic duct -> common bile duct -> duodenum
C. Right and left hepatic ducts -> common hepatic duct -> common bile duct -> duodenum(correct answer)
D. Common bile duct -> cystic duct -> hepatic ducts -> duodenum
Answer: C.The figure shows the right and left hepatic ducts joining to form the common hepatic duct, which continues as the common bile duct that enters the duodenum; the cystic duct connects the gallbladder to this pathway.
Q2. Which statement best distinguishes the gastrointestinal (GI) tract from the accessory digestive organs?
A. The GI tract is a continuous tube from mouth to anus that includes the oral cavity, pharynx, oesophagus, stomach, small intestine and large intestine, whereas the salivary glands, liver, gallbladder and pancreas are accessory digestive organs.(correct answer)
B. The accessory organs form the tube from mouth to anus, while the GI tract consists only of glands.
C. The GI tract consists only of glands, while the accessory organs form the main tube.
D. Both the GI tract and the accessory organs together form the single continuous tube from mouth to anus.
Answer: A.The text classifies the digestive system into the GI tract, a continuous tube with six listed parts, and the accessory organs, namely the salivary glands, liver, gallbladder and pancreas, which are listed separately.
Q3. Which sequence correctly traces the path of material through the large intestine region as shown in Figure 9.1?
D. Cecum → transverse colon → ascending colon → descending colon → anus → rectum
Answer: C.The parts of the colon are named for the direction of flow shown in Figure 9.1: after the cecum, material passes through the ascending, then transverse, then descending colon before reaching the rectum and anus.
Q4. Which statement best summarizes the roles played by the tongue in the oral cavity and at the start of swallowing?
A. It secretes saliva and thereby moistens the bolus
B. It lowers the epiglottis and closes the opening of the trachea
C. It selects food through its taste buds and moves upward and backward to force the bolus to the back of the oral cavity(correct answer)
D. It closes the passage between the nasal cavity and the pharynx
Answer: C.The tongue selects food via taste buds and, during swallowing, moves upward and backward to push the bolus back; closing the nasal passage is done by the soft palate, and the epiglottis is lowered by the upward movement of the larynx.
Q5. Which statement correctly contrasts antiperistalsis with normal peristalsis?
A. Antiperistalsis occurs only in the oesophagus, while normal peristalsis occurs only in the intestines
B. Antiperistalsis is triggered by low blood glucose, while normal peristalsis is triggered by vomiting
C. Antiperistalsis mixes food with digestive secretions, while normal peristalsis increases the efficiency of absorption
D. In antiperistalsis the waves reverse and push food from the intestines towards the stomach and oral cavity, whereas normal peristalsis squeezes food down along the alimentary canal(correct answer)
Answer: D.Antiperistalsis is the reversal of peristaltic movements that pushes food backwards towards the stomach and oral cavity, whereas peristalsis normally squeezes food down along the oesophagus and other parts of the canal.
Q6. Which statement correctly distinguishes hunger contractions from antiperistalsis?
A. Hunger contractions are triggered by high blood glucose, whereas antiperistalsis is triggered by low blood glucose
B. Hunger contractions occur only in the large intestine, whereas antiperistalsis occurs only in the oesophagus
C. Hunger contractions push food into the oral cavity, whereas antiperistalsis causes hunger pangs
D. Hunger contractions are peristaltic movements triggered by low blood glucose that cause hunger pangs, whereas antiperistalsis is a reversal of peristaltic movements that can lead to vomiting(correct answer)
Answer: D.Peristaltic hunger contractions are triggered by low blood glucose and produce hunger pangs, whereas antiperistalsis reverses the normal movement of food, pushing it back towards the oral cavity and leading to vomiting.
Q7. Which of the following is the correct sequence of events after food (bolus) enters the stomach?
A. Pepsin digests proteins -> HCl activates pepsinogen -> gastric glands secrete gastric juice -> chyme is released into the small intestine
B. Gastric glands secrete gastric juice -> HCl activates pepsinogen -> pepsin digests proteins -> chyme is released into the small intestine(correct answer)
C. Gastric glands secrete gastric juice -> pepsin digests proteins -> HCl activates pepsinogen -> chyme is released into the small intestine
D. Gastric glands secrete gastric juice -> HCl activates pepsinogen -> chyme is released into the small intestine -> pepsin digests proteins
Answer: B.When the bolus enters the stomach, the gastric glands secrete gastric juice. The H+ ions of HCl activate pepsinogen into pepsin, which digests proteins, and the resulting chyme is released through the pyloric sphincter about 3-4 hours after the meal.
Q8. Which option correctly contrasts the absorption of simple sugars and amino acids with the absorption of the products of fat digestion?
A. Both are absorbed directly into the lacteals and reach the liver through the thoracic duct
B. Sugars and amino acids are absorbed by diffusion or active transport into blood capillaries, while fatty acids and glycerol are absorbed passively and enter lacteals as chylomicrons(correct answer)
C. Sugars and amino acids enter the lacteals, while fatty acids and glycerol enter blood capillaries
D. Sugars require passive transport while fatty acids require active transport into blood capillaries
Answer: B.Sugars and amino acids cross epithelial cells by diffusion or active transport and enter blood capillaries leading to the hepatic portal vein; fatty acids and glycerol enter passively, are repackaged as chylomicrons and pass into lacteals.
Q9. Assertion: Inside the epithelial cells of the villi, fatty acids and glycerol combine to form triglycerides.
Reason: Fatty acids and glycerol are absorbed into the epithelial cells of villi by passive transport.
A. Both Assertion and Reason are true and the Reason is a correct explanation of the Assertion
B. Both Assertion and Reason are true but the Reason is NOT a correct explanation of the Assertion(correct answer)
C. Assertion is true but the Reason is false
D. Assertion is false but the Reason is true
Answer: B.Both statements are correct: the products of fat digestion enter epithelial cells passively and inside the villi they recombine into triglycerides. However, the mode of absorption does not explain why the recombination occurs.
Q10. Arrange the following events of fat absorption and transport in the correct order:
(i) Chylomicrons enter the lacteals of villi
(ii) Fatty acids and glycerol are absorbed by passive transport into epithelial cells of villi
(iii) Triglycerides coated with proteins form chylomicrons
(iv) Chylomicrons pass via the thoracic lymphatic duct into the bloodstream
(v) Plasma enzymes hydrolyse chylomicrons and fats ultimately enter body cells as fatty acids and glycerol
A. (ii) -> (iii) -> (i) -> (iv) -> (v)(correct answer)
B. (ii) -> (i) -> (iii) -> (iv) -> (v)
C. (iii) -> (ii) -> (i) -> (iv) -> (v)
D. (ii) -> (iii) -> (iv) -> (i) -> (v)
Answer: A.After passive absorption, fatty acids and glycerol recombine into triglycerides, which are coated with proteins to form chylomicrons; these enter lacteals, travel via the thoracic lymphatic duct to the blood, where plasma enzymes release fats for body cells.