Nokea
What is the role of the stomach in digestion?
- A. Mechanical digestion of food
- B. Chemical digestion of proteins
- C. Absorption of nutrients
- D. Neutralization of stomach acid
Correct Answer: B
Rationale: The correct answer is B: Chemical digestion of proteins. The stomach produces hydrochloric acid and enzymes like pepsin to break down proteins into peptides and amino acids. This process is essential for protein digestion. Mechanical digestion (A) occurs mainly in the mouth and intestines. Absorption of nutrients (C) primarily takes place in the small intestine. Neutralization of stomach acid (D) is not the primary role of the stomach; rather, the stomach maintains an acidic environment for digestion.
You may also like to solve these questions
How many teeth will be produced in an average lifetime?
- A. 20
- B. 32
- C. 30
- D. 52
Correct Answer: B
Rationale: The correct answer is B: 32. An average adult human has 32 permanent teeth, including 8 incisors, 4 canines, 8 premolars, and 12 molars. These teeth are developed during childhood and adolescence and are meant to last a lifetime, barring any dental issues. Option A (20) is too low for adult teeth count, C (30) is close but incorrect, and D (52) is too high and includes extra teeth, such as wisdom teeth which not everyone develops.
Which of these is involved in the chemical digestion of protein?
- A. pancreatic amylase
- B. trypsin
- C. sucrase
- D. pancreatic nuclease
Correct Answer: B
Rationale: The correct answer is B: trypsin. Trypsin is an enzyme produced by the pancreas that specifically breaks down proteins into smaller peptides. It works in the small intestine to continue the process of protein digestion. Pancreatic amylase (A) breaks down carbohydrates, sucrase (C) breaks down sucrose, and pancreatic nuclease (D) breaks down nucleic acids, not proteins. Therefore, trypsin is the only enzyme involved in the chemical digestion of protein among the choices provided.
The colonic mucosal cells are very efficient in:
- A. Converting primary bile acids into secondary bile acids
- B. Converting bilirubin into stercobilinogen
- C. Absorption of aromatic amino acids
- D. Absorption of sodium
Correct Answer: D
Rationale: The correct answer is D: Absorption of sodium. Colonic mucosal cells are efficient in absorbing sodium through active transport processes. Sodium absorption helps in maintaining fluid and electrolyte balance. Choices A, B, and C are incorrect because primary bile acids are converted into secondary bile acids in the liver, bilirubin is converted into stercobilinogen in the intestines, and aromatic amino acids are mostly absorbed in the small intestine, not the colon.
Which part of the digestive system is responsible for the absorption of nutrients?
- A. small intestine
- B. stomach
- C. pancreas
- D. liver
Correct Answer: A
Rationale: The correct answer is A, the small intestine, because it is the primary site for nutrient absorption in the digestive system. The small intestine is lined with villi and microvilli, increasing its surface area for efficient absorption. It contains specialized cells that transport nutrients into the bloodstream for distribution to the body. The stomach (B) primarily breaks down food using digestive enzymes and acids, while the pancreas (C) secretes digestive enzymes but does not directly absorb nutrients. The liver (D) plays a role in bile production and detoxification, but nutrient absorption occurs mainly in the small intestine.
The stomach is unique to the GI tract because it contains
- A. circular smooth muscle.
- B. longitudinal smooth muscle.
- C. skeletal muscle.
- D. oblique smooth muscle.
Correct Answer: D
Rationale: The correct answer is D: oblique smooth muscle. The stomach is unique in the GI tract because it contains an additional layer of muscle fibers called the oblique muscle layer. This layer allows for more efficient mixing and churning of food, aiding in digestion. Circular smooth muscle (choice A) and longitudinal smooth muscle (choice B) are present in various parts of the GI tract but are not unique to the stomach. Skeletal muscle (choice C) is not found in the stomach as the muscles responsible for its movement are smooth muscle.