Nokea
Trypsinogen when activated by ______ will break down proteins in the ______.
- A. enterokinase; pancreatic ducts
- B. trypsin; small intestine
- C. secretin; pancreatic ducts
- D. enterokinase; small intestine
Correct Answer: D
Rationale: The correct answer is D: enterokinase; small intestine. Enterokinase is an enzyme that activates trypsinogen into trypsin in the small intestine. Trypsin is then responsible for breaking down proteins in the small intestine. Enterokinase is not found in the pancreatic ducts, eliminating choices A and C. Trypsinogen is not activated by itself, so choice B is incorrect. In summary, enterokinase activates trypsinogen into trypsin in the small intestine, allowing for protein digestion.
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The pharyngeal phase of swallowing:
- A. Is partially voluntary
- B. Includes opening of the upper oesophageal sphincter
- C. Includes the peristaltic activity of the upper third of the oesophagus
- D. Is associated with the opening of the glottis
Correct Answer: C
Rationale: The correct answer is C because the pharyngeal phase of swallowing involves the peristaltic activity of the upper third of the esophagus, pushing the food bolus towards the stomach. This phase is involuntary and is controlled by the swallowing reflex. Choices A, B, and D are incorrect because the pharyngeal phase is entirely involuntary, the upper esophageal sphincter opens during the esophageal phase, and the opening of the glottis is associated with protection of the airway during swallowing, not the pharyngeal phase.
The pancreas and liver release their secretions into the
- A. stomach.
- B. ileum.
- C. duodenum.
- D. jejunum.
Correct Answer: C
Rationale: The correct answer is C: duodenum. The pancreas and liver release their secretions, such as pancreatic enzymes and bile, into the duodenum. This is because the duodenum is the first part of the small intestine where digestion primarily occurs. The stomach (A) is responsible for initial digestion of food, while the ileum (B) and jejunum (D) are parts of the small intestine where absorption of nutrients occurs, not secretion release.
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.
Where does the majority of carbohydrate digestion occur?
- A. stomach
- B. small intestine
- C. mouth
- D. esophagus
Correct Answer: C
Rationale: The majority of carbohydrate digestion occurs in the mouth. This is because the enzyme amylase, present in saliva, begins breaking down carbohydrates into simpler sugars like maltose. The process starts in the mouth as the food is chewed and mixed with saliva, creating a bolus that can be easily swallowed. In the stomach, the acidic environment actually inhibits amylase activity, so minimal carbohydrate digestion occurs there. The small intestine is where further digestion and absorption of carbohydrates primarily happen, but the initial breakdown in the mouth is crucial. The esophagus is not involved in digestion, but rather in the transportation of food to the stomach.
Bile pigments:
- A. Are derived from globin portion of hemoglobin.
- B. Help in fat digestion and absorption.
- C. Are conjugated in the liver mainly with sulphate.
- D. Their level increases in blood in liver disease.
Correct Answer: D
Rationale: The correct answer is D because bile pigments, such as bilirubin, increase in the blood in liver disease due to impaired liver function. Bilirubin is a waste product from the breakdown of red blood cells and is normally processed by the liver. Elevated levels of bile pigments in the blood are a common indicator of liver dysfunction.
Choice A is incorrect because bile pigments are derived from heme, not the globin portion of hemoglobin.
Choice B is incorrect because bile pigments aid in the emulsification of fats but do not directly help in fat digestion and absorption.
Choice C is incorrect as bile pigments are conjugated with glucuronic acid, not sulphate, in the liver.