Human Anatomy and Physiology - Digestive and Respiratory Systems MCQs 2026

The enzyme pepsin, which digests proteins, is active in the highly acidic environment of the

1. A Mouth ✓
2. B Small intestine ✓
3. C Stomach ✓
4. D Large intestine ✓

The condition in which stomach acid flows back into the esophagus, causing heartburn, is called

1. A Peptic ulcer ✓
2. B Appendicitis ✓
3. C Gastroesophageal reflux disease (GERD) ✓
4. D Cirrhosis ✓

The average adult human takes approximately how many breaths per minute at rest

1. A 12 to 20 ✓
2. B 40 to 50 ✓
3. C 2 to 5 ✓
4. D 60 to 80 ✓

The total surface area of human lungs available for gas exchange is approximately equal to the area of a

1. A Small classroom ✓
2. B Tennis court ✓
3. C Football field ✓
4. D Basketball court ✓

Enzymes that specifically digest nucleic acids in the small intestine are called

1. A Lipases ✓
2. B Proteases ✓
3. C Amylases ✓
4. D Nucleases ✓

The main function of the appendix, once thought vestigial, is now associated with

1. A Fat digestion ✓
2. B Vitamin K synthesis ✓
3. C Housing beneficial gut bacteria ✓
4. D Protein absorption ✓

The salivary glands that produce the largest volume of saliva are the

1. A Sublingual glands ✓
2. B Parotid glands ✓
3. C Submandibular glands only ✓
4. D Buccal glands ✓

The pH of gastric juice in the stomach is typically

1. A Strongly acidic (around pH 1.5-3.5) ✓
2. B Neutral (pH 7) ✓
3. C Strongly alkaline (pH 9-10) ✓
4. D Slightly acidic (pH 6) ✓

The process of breathing in (inhalation) is also called

1. A Expiration ✓
2. B Exhalation ✓
3. C Inspiration ✓
4. D Respiration ✓

The small sac-like structures at the end of bronchioles where gas exchange occurs are surrounded by a network of

1. A Lymph vessels ✓
2. B Nerve fibers ✓
3. C Muscle fibers ✓
4. D Capillaries ✓

Smoking is most strongly linked to which respiratory disease

1. A Common cold ✓
2. B Tonsillitis ✓
3. C Lung cancer ✓
4. D Hiccups ✓

The disease in which the alveolar walls are progressively destroyed, reducing surface area for gas exchange, is

1. A Asthma ✓
2. B Emphysema ✓
3. C Laryngitis ✓
4. D Bronchitis ✓

Pneumonia is a condition characterized by

1. A Inflammation and fluid accumulation in the alveoli ✓
2. B Narrowing of the trachea only ✓
3. C Excess saliva production ✓
4. D Loss of taste buds ✓

A person suffering from asthma experiences difficulty breathing mainly due to

1. A Alveolar collapse ✓
2. B Excess red blood cells ✓
3. C Diaphragm paralysis ✓
4. D Constriction of bronchial airways ✓

The exchange of gases between alveolar air and blood is primarily driven by differences in

1. A Blood pressure ✓
2. B Temperature ✓
3. C Partial pressure of gases ✓
4. D pH levels ✓

The thin membrane that lines the lungs and chest cavity, reducing friction during breathing, is the

1. A Peritoneum ✓
2. B Pleura ✓
3. C Pericardium ✓
4. D Diaphragm membrane ✓

The maximum amount of air that can be exhaled after a maximum inhalation is called

1. A Vital capacity ✓
2. B Tidal volume ✓
3. C Residual volume ✓
4. D Inspiratory reserve volume ✓

The volume of air inhaled or exhaled in a normal, relaxed breath is called

1. A Vital capacity ✓
2. B Residual volume ✓
3. C Total lung capacity ✓
4. D Tidal volume ✓

The part of the brain that primarily controls the rhythm of breathing is the

1. A Cerebellum ✓
2. B Medulla oblongata ✓
3. C Cerebrum ✓
4. D Hypothalamus ✓

Most carbon dioxide in the blood is transported in the form of

1. A Dissolved gas in plasma ✓
2. B Carboxyhemoglobin ✓
3. C Bicarbonate ions ✓
4. D Carbonic acid crystals ✓

Oxygen is mainly transported in the blood bound to

1. A Hemoglobin in red blood cells ✓
2. B Plasma proteins ✓
3. C White blood cells ✓
4. D Platelets ✓

Gas exchange in the alveoli occurs primarily by the process of

1. A Active transport ✓
2. B Osmosis ✓
3. C Facilitated diffusion ✓
4. D Simple diffusion ✓

The windpipe that carries air from the larynx to the bronchi is called the

1. A Esophagus ✓
2. B Trachea ✓
3. C Bronchiole ✓
4. D Pharynx ✓

The flap of tissue that prevents food from entering the trachea during swallowing is the

1. A Uvula ✓
2. B Larynx ✓
3. C Epiglottis ✓
4. D Glottis ✓

The voice box, containing the vocal cords, is known as the

1. A Larynx ✓
2. B Pharynx ✓
3. C Trachea ✓
4. D Epiglottis ✓

During inhalation, the diaphragm

1. A Relaxes and moves upward ✓
2. B Stays stationary ✓
3. C Expands laterally only ✓
4. D Contracts and moves downward ✓

The muscle primarily responsible for breathing, separating the thoracic and abdominal cavities, is the

1. A Intercostal muscle ✓
2. B Diaphragm ✓
3. C Trapezius ✓
4. D Pectoralis ✓

The primary site of gas exchange in the human respiratory system is the

1. A Alveoli ✓
2. B Bronchi ✓
3. C Trachea ✓
4. D Larynx ✓

The valve that regulates the passage of partially digested food from the stomach to the duodenum is the

1. A Cardiac sphincter ✓
2. B Ileocecal valve ✓
3. C Pyloric sphincter ✓
4. D Anal sphincter ✓

The valve that prevents backflow of food from the stomach into the esophagus is the

1. A Pyloric sphincter ✓
2. B Ileocecal valve ✓
3. C Bicuspid valve ✓
4. D Cardiac (lower esophageal) sphincter ✓

Starch is ultimately broken down into which simple sugar for absorption

1. A Fructose ✓
2. B Glucose ✓
3. C Galactose ✓
4. D Sucrose ✓

The end product of protein digestion that is absorbed into the bloodstream is

1. A Glucose ✓
2. B Fatty acids ✓
3. C Amino acids ✓
4. D Glycerol ✓

The hormone gastrin stimulates the secretion of

1. A Gastric acid ✓
2. B Bile ✓
3. C Insulin ✓
4. D Saliva ✓

The hormone that stimulates the gallbladder to release bile and the pancreas to release digestive enzymes is

1. A Gastrin ✓
2. B Secretin ✓
3. C Insulin ✓
4. D Cholecystokinin (CCK) ✓

Vitamin B12 absorption in the terminal ileum requires a substance called

1. A Bile salts ✓
2. B Intrinsic factor ✓
3. C Pepsinogen ✓
4. D Gastrin ✓

The digestion of fats is aided by bile through a process called

1. A Hydrolysis ✓
2. B Absorption ✓
3. C Emulsification ✓
4. D Peristalsis ✓

Undigested food waste is stored temporarily before elimination in the

1. A Rectum ✓
2. B Duodenum ✓
3. C Ileum ✓
4. D Esophagus ✓

The primary function of the large intestine (colon) is

1. A Protein digestion ✓
2. B Absorption of water and electrolytes ✓
3. C Fat emulsification ✓
4. D Enzyme secretion for carbohydrate digestion ✓

Finger-like projections in the small intestine that increase surface area for absorption are called

1. A Rugae ✓
2. B Cilia ✓
3. C Papillae ✓
4. D Villi ✓

The pancreas secretes which enzyme to digest proteins in the small intestine

1. A Pepsin ✓
2. B Ptyalin ✓
3. C Trypsin ✓
4. D Renin ✓

The organ that stores and concentrates bile before releasing it into the small intestine is the

1. A Gallbladder ✓
2. B Pancreas ✓
3. C Liver ✓
4. D Spleen ✓

Bile, which emulsifies fats, is produced by the

1. A Pancreas ✓
2. B Stomach ✓
3. C Gallbladder ✓
4. D Liver ✓

The three parts of the small intestine, in order from the stomach, are

1. A Ileum, jejunum, duodenum ✓
2. B Duodenum, jejunum, ileum ✓
3. C Jejunum, duodenum, ileum ✓
4. D Duodenum, ileum, jejunum ✓

Most digestion and absorption of nutrients occurs in the

1. A Stomach ✓
2. B Large intestine ✓
3. C Small intestine ✓
4. D Esophagus ✓

Peristalsis refers to

1. A Rhythmic muscular contractions that move food along the digestive tract ✓
2. B The mixing of food with saliva ✓
3. C The absorption of nutrients in the intestine ✓
4. D The secretion of bile by the liver ✓

The muscular tube that connects the throat to the stomach is the

1. A Trachea ✓
2. B Pharynx ✓
3. C Larynx ✓
4. D Esophagus ✓

Hydrochloric acid in the stomach is secreted by

1. A Chief cells ✓
2. B Parietal cells ✓
3. C Goblet cells ✓
4. D Mucous cells ✓

The enzyme present in saliva that breaks down starch is

1. A Pepsin ✓
2. B Salivary amylase (ptyalin) ✓
3. C Lipase ✓
4. D Trypsin ✓

Digestion of carbohydrates begins in the

1. A Mouth ✓
2. B Stomach ✓
3. C Small intestine ✓
4. D Large intestine ✓

The process of breaking down food into smaller absorbable molecules is called

1. A Egestion ✓
2. B Absorption ✓
3. C Assimilation ✓
4. D Digestion ✓