Which statements are correct ?
(A) During inspiration intra pulmonary pressure is less than the atmospheric pressure.
(B) During expiration diaphragm contract.
(C) Epiglottis is bony flap which prevent entry of food into the larynx.
(D) During forceful expiration abdominal muscles contract.

Options

A. A, B, C, D are correct
B. A and D are correct
C. B and C are correct
D. A and C are correct

Answer

To determine which statements are correct, we will analyze each statement one by one:

**Step 1: Analyze Statement A**
- Statement A: "During inspiration, intrapulmonary pressure is less than the atmospheric pressure."
- Explanation: During inspiration, the diaphragm and external intercostal muscles contract, increasing the volume of the thoracic cavity. This increase in volume leads to a decrease in intrapulmonary pressure, making it lower than the atmospheric pressure. Therefore, this statement is **true**.

**Step 2: Analyze Statement B**
- Statement B: "During expiration, diaphragm contracts."
- Explanation: During expiration, the diaphragm actually relaxes, allowing the lungs to decrease in volume and expel air. Therefore, this statement is **false**.

**Step 3: Analyze Statement C**
- Statement C: "Epiglottis is a bony flap which prevents entry of food into the larynx."
- Explanation: The epiglottis is not a bony structure; rather, it is made of cartilage. It acts as a flap that closes over the larynx during swallowing to prevent food from entering the windpipe. Therefore, this statement is **false**.

**Step 4: Analyze Statement D**
- Statement D: "During forceful expiration, abdominal muscles contract."
- Explanation: During forceful expiration, the abdominal muscles do contract to help push the diaphragm upwards and expel air more forcefully from the lungs. Therefore, this statement is **true**.

**Conclusion:**
- The correct statements are A and D.
- Therefore, the correct answers are:
- A: True
- B: False
- C: False
- D: True

**Final Answer: A and D are correct.**

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