This question asks to identify the specific lung volume that remains in the lungs even after a maximal exhalation. Understanding the definitions of different lung volumes and capacities is key to answering this question.
The volume of air that remains in the lungs even after a forcible expiration is known as the Residual Volume (RV). This volume cannot be expelled and serves to keep the alveoli open and prevent the lungs from completely collapsing.
D) Residual Volume (RV) — This is the volume of air remaining in the lungs after a maximal forceful expiration. It cannot be exhaled.
The question asks for the components that constitute the Vital Capacity (VC) of the lungs. Vital Capacity is a key physiological measurement representing the maximum amount of air a person can expel from the lungs after a maximum inhalation. To answer this, we need to understand the definitions of various lung volumes and capacities.
Correct Option: D) IRV + TV + ERV. This option correctly represents the sum of Inspiratory Reserve Volume, Tidal Volume, and Expiratory Reserve Volume, which together constitute the Vital Capacity.
The question asks for the definition of Total Lung Capacity (TLC). To answer this, we need to understand the various lung volumes and capacities and how they combine to form TLC.
C) Vital Capacity + Residual Volume (RV + ERV + TV + IRV) – This option correctly defines Total Lung Capacity. It explicitly states that TLC is the sum of Vital Capacity and Residual Volume, and then further breaks down Vital Capacity into its components (RV + ERV + TV + IRV), which collectively represent all four primary lung volumes. Thus, it accurately represents the total air the lungs can hold.
The question asks to identify the components that sum up to form Functional Residual Capacity (FRC). This requires knowledge of lung volumes and capacities, which are fundamental concepts in respiratory physiology.
Therefore, the formula for Functional Residual Capacity is:
\[ \text{FRC} = \text{ERV} + \text{RV} \]Correct Option: C) ERV + RV — This option correctly identifies Functional Residual Capacity (FRC) as the sum of Expiratory Reserve Volume (ERV) and Residual Volume (RV).
The question asks for the instrument used to measure respiratory volumes and assess pulmonary function. This requires identifying the specific medical device designed for this purpose.
C) Spirometer is the correct instrument. A spirometer measures the amount (volume) and/or speed (flow) of air that can be inhaled and exhaled. It is widely used to diagnose and monitor respiratory conditions such as asthma, COPD, and restrictive lung diseases.
The question asks for the approximate partial pressure of oxygen (pOâ‚‚) in the alveolar air. This is a standard physiological value that candidates for competitive exams are expected to know. We need to recall the typical partial pressures of gases in atmospheric air, alveolar air, and arterial blood.
C) 104 mm Hg — This is the physiologically accurate approximate partial pressure of oxygen in the alveolar air.