Problem 33 - Objective Biology for NEET

Question

Select the incorrect statement from the following: (a) Pleural fluid reduces friction on the lung surface. (b) The anatomical setup of lungs in thorax is such that any change in the volume of the thoracic cavity will be reflected in the lung (pulmonary) cavity. Such an arrangement is essential for breathing, as we cannot directly alter the pulmonary volume. (c) The tracheae, primary, secondary and tertiary bronchi and initial bronchioles are supported by complete cartilaginous rings. (d) During swallowing, the glottis can be covered by a thin elastic cartilaginous flap called epiglottis to prevent the entry of food into the larynx.

Step-by-Step Solution

Answer

The incorrect statement is (c). The tracheae, primary, secondary, and tertiary bronchi, and initial bronchioles are not supported by complete cartilaginous rings.

Step 1: Identify the Correct Statements

First, let us verify each statement one by one to identify the accurate ones. We start with statement (a): 'Pleural fluid reduces friction on the lung surface.' This statement is correct as pleural fluid in the space between the two pleural layers indeed helps reduce friction during the movement of lungs. Similarly, statement (d) is also accurate as the epiglottis indeed prevents food from entering the larynx during swallowing.

Step 2: Further Investigation of Statements

Next, let’s move on to statement (b). 'The anatomical setup of lungs in thorax is such that any change in the volume of the thoracic cavity will be reflected in the lung (pulmonary) cavity. Such an arrangement is essential for breathing, as we cannot directly alter the pulmonary volume.' This statement is factually correct. The change in thoracic volume during inhalation and exhalation facilitates the corresponding change in pulmonary volume, which ultimately aids in the process of respiration.

Step 3: Identify the Incorrect Statement

Finally, let’s examine statement (c): 'The tracheae, primary, secondary and tertiary bronchi, and initial bronchioles are supported by complete cartilaginous rings.' This is the incorrect statement. Although the trachea is supported by complete ring-like structures of cartilage, bronchi and bronchioles aren't supported by complete cartilaginous rings. Instead, they have irregular cartilaginous plates or no cartilaginous support at all.