Practice free Breathing and Exchange of Gases (Zoology) NEET multiple-choice questions online with instant answers and detailed explanations. No login required.
The thoracic chamber is formed dorsally by the vertebral column, ventrally by the sternum, laterally by the ribs, and on the lower side by the:
The NCERT text describes the thoracic chamber as formed 'dorsally by the vertebral column, ventrally by the sternum, laterally by the ribs and on the lower side by the dome-shaped diaphragm.'
Which of the following is NOT one of the steps involved in respiration as listed in the NCERT text?
The NCERT lists five steps of respiration: (i) Breathing or pulmonary ventilation (ii) Diffusion of gases (O2 and CO2) across alveolar membrane (iii) Transport of gases by the blood (iv) Diffusion of O2 and CO2 between blood and tissues (v) Utilisation of O2 by the cells for catabolic reactions. Production of hemoglobin is a physiological process, not a direct step in gas exchange and cellular respiration itself.
What is the average breathing rate for a healthy human per minute?
The NCERT states: 'On an average, a healthy human breathes 12-16 times/minute.'
Which of the following describes the correct sequence of events during normal inspiration?
According to the NCERT text, 'Inspiration can occur if the pressure within the lungs (intra-pulmonary pressure) is less than the atmospheric pressure... This is achieved by the contraction of diaphragm which increases the volume of thoracic chamber in antero-posterior axis. The contraction of external inter-costal muscles lifts up the ribs and the sternum causing an increase in the volume of the thoracic chamber in the dorso-ventral axis. The overall increase in the thoracic volume causes a similar increase in pulmonary volume. An increase in pulmonary volume decreases the intra-pulmonary pressure to less than the atmospheric pressure which forces the air from outside to move into the lungs, i.e., inspiration (Figure 14.2a).'
Which of the following respiratory volumes or capacities can be directly measured using a spirometer?
The NCERT states, 'The volume of air involved in breathing movements can be estimated by using a spirometer which helps in clinical assessment of pulmonary functions.' While many volumes are defined, Residual Volume (RV) and consequently capacities that include RV (like TLC and FRC) cannot be measured directly by a spirometer, as some air always remains in the lungs. Inspiratory Reserve Volume (IRV) is a measurable change in volume during forced inspiration.
What is the primary factor that drives the process of expiration during normal, quiet breathing?
The NCERT states, 'Relaxation of the diaphragm and the inter-costal muscles returns the diaphragm and sternum to their normal positions and reduce the thoracic volume and thereby the pulmonary volume. This leads to an increase in intra-pulmonary pressure to slightly above the atmospheric pressure causing the expulsion of air from the lungs, i.e., expiration (Figure 14.2b).' Thus, the increase in intra-pulmonary pressure above atmospheric pressure is the primary driver.
The conducting part of the respiratory system performs all the following functions EXCEPT:
The NCERT states, 'The conducting part transports the atmospheric air to the alveoli, clears it from foreign particles, humidifies and also brings the air to body temperature. Exchange part is the site of actual diffusion of O2 and CO2 between blood and atmospheric air.' Thus, the conducting part does not serve as the site of gas diffusion.
A healthy human breathes at an average rate of:
The NCERT states, 'On an average, a healthy human breathes 12-16 times/minute.'
Which of the following correctly represents Inspiratory Capacity (IC)?
According to the NCERT, 'Inspiratory Capacity (IC): Total volume of air a person can inspire after a normal expiration. This includes tidal volume and inspiratory reserve volume (TV+IRV).'
The thoracic chamber is described as anatomically an air-tight chamber. Which structures form its dorsal and ventral boundaries, respectively?
The NCERT states, 'The thoracic chamber is formed dorsally by the vertebral column, ventrally by the sternum, laterally by the ribs and on the lower side by the dome-shaped diaphragm.'
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