Question

Which of the following are responsible for vomition?

(A). Apomorphine
(B). Allopurinol
(C). Toxic gastric irritation
(D). Pylorous obstruction

Choose the correct answer from the options given below:

• A. (A), (C) and (D) only.
• B. (B), (C) and (D) only.
• C. (A), (B), (C) and (D).
• D. (B) only.

Hint:

Vomiting can be triggered centrally (by drugs like Apomorphine acting on the brain's CTZ) or peripherally (by local factors like gastric irritation or pyloric obstruction acting on the stomach).

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Vomiting (emesis) is a complex reflex coordinated by the emetic center in the medulla oblongata, triggered by local gastric irritation, mechanical obstruction, or chemical stimulation of the Chemoreceptor Trigger Zone (CTZ).

Step 2: Detailed Explanation:
Let us evaluate each factor:
- Apomorphine (A): A potent dopamine receptor agonist that directly acts on the CTZ in the brainstem to induce emesis. It is used clinically as an emetic agent. Thus, (A) is responsible.
- Allopurinol (B): Primarily used to treat gout by inhibiting xanthine oxidase; it does not typically induce or cause vomiting as a primary effect.
- Toxic gastric irritation (C): Directly irritates the mucosal lining of the stomach, sending vagal and sympathetic afferent signals to the medulla to trigger the vomiting reflex. Thus, (C) is responsible.
- Pyloric obstruction (D): Restricts the flow of chyme from the stomach into the duodenum, causing gastric distension and triggering reverse peristalsis and vomiting. Thus, (D) is responsible.
Therefore, (A), (C), and (D) are responsible for inducing vomiting.

Step 3: Final Answer:
The correct option is 1, which corresponds to (A), (C) and (D) only.