Respiration involves several sequential physiological steps. Consider the statements below:
I. Breathing or pulmonary ventilation by which atmospheric air is drawn in and CO2-rich alveolar air is released out. II. Diffusion of gases (O2 and CO2) across alveolar membrane. III. Transport of gases by the blood. IV. Utilization of CO2 by tissue cells to generate oxygen.
Statements I, II, and III are correct steps in respiration. Statement IV is incorrect because cells utilize O2 for catabolic reactions and release CO2, not utilizing CO2 to generate O2.
Question 22 of 100
📘 CLASS XI
Which of the following statements correctly describe the steps of respiration following gas transport by blood?
I. Diffusion of O2 and CO2 between blood and tissues. II. Utilisation of O2 by the cells for catabolic reactions. III. Resultant release of CO2 by cells during cellular respiration. IV. Direct conversion of atmospheric nitrogen into amino acids in alveoli.
Statements I, II, and III are correct steps of respiration at tissue/cellular level. Statement IV is incorrect because atmospheric nitrogen is not converted into amino acids in alveoli.
Question 23 of 100
📘 CLASS XI
Analyze the statements regarding pleural membranes and fluid:
I. Lungs are situated in the thoracic chamber and enclosed by a single-layered pericardium. II. Pleural fluid is present between the outer and inner pleural membranes. III. Pleural fluid increases friction on the lung surface during breathing. IV. Outer pleural membrane is in contact with thoracic lining while inner membrane is in contact with lung surface.
Statements II and IV are correct: Pleural fluid lies between outer and inner pleural membranes, outer membrane contacts thoracic lining, and inner membrane contacts lung surface. Statement I is incorrect (double-layered pleura, not single pericardium). Statement III is incorrect because pleural fluid reduces friction.
Question 24 of 100
📘 CLASS XI
Consider the following statement combinations regarding cartilaginous rings in the respiratory tract:
I. Present in the trachea. II. Present in primary, secondary, and tertiary bronchi. III. Present in initial bronchioles. IV. Present in alveoli.
Statements I, II, and III are correct: Trachea, primary/secondary/tertiary bronchi, and initial bronchioles are supported by incomplete cartilaginous rings. Statement IV is incorrect because alveoli lack cartilaginous rings.
Question 25 of 100
📘 CLASS XI
Regarding the human larynx, analyze the following statements:
I. It is a cartilaginous box helping in sound production. II. It is commonly referred to as the sound box. III. Glottis is the opening of the larynx into the pharynx/trachea region. IV. During swallowing, epiglottis covers the glottis to prevent entry of food into larynx.
All four statements (I, II, III, and IV) are correct: Larynx is a cartilaginous sound box; glottis is its opening covered by elastic cartilaginous epiglottis during swallowing to prevent food entering larynx.
Question 26 of 100
📘 CLASS XI
Examine the statements regarding human trachea division and position:
I. Trachea is a straight tube. II. Extends up to the mid-thoracic cavity. III. Divides at the level of the 5th thoracic vertebra. IV. Divides into right and left primary bronchi.
All four statements are correct: Trachea is a straight tube extending to the mid-thoracic cavity, dividing at the 5th thoracic vertebra into right and left primary bronchi.
Question 27 of 100
📘 CLASS XI
Which of the following statements regarding the conducting part of the respiratory system are correct?
I. Starts from external nostrils and extends up to terminal bronchioles. II. Transports atmospheric air to alveoli. III. Clears incoming air from foreign particles. IV. Humidifies air and brings it to body temperature.
All four statements are correct: The conducting part spans external nostrils to terminal bronchioles and functions to transport air, clear foreign particles, humidify air, and bring it to body temperature.
Question 28 of 100
📘 CLASS XI
Consider the following statements regarding the respiratory/exchange part of human lungs:
I. Consists of alveoli and their ducts. II. Represents the site of actual diffusion of O2 and CO2 between blood and atmospheric air. III. Has thick, non-vascularized walls to prevent gas leakage. IV. Includes the trachea and main bronchi.
Statements I and II are correct: Alveoli and their ducts form the exchange part where actual O2 and CO2 diffusion takes place. Statements III and IV are incorrect because alveoli are very thin and vascularised, and trachea/main bronchi belong to the conducting part.
Question 29 of 100
📘 CLASS XI
Analyze the anatomical boundaries of the thoracic cavity:
I. Dorsal boundary = Vertebral column. II. Ventral boundary = Sternum. III. Lateral boundary = Ribs. IV. Lower boundary = Dome-shaped diaphragm.
All four statements are correct: The thoracic chamber is formed dorsally by vertebral column, ventrally by sternum, laterally by ribs, and lower side by dome-shaped diaphragm.
Question 30 of 100
📘 CLASS XI
Why is the air-tight setup of the thoracic chamber essential for human breathing?
I. Human lungs cannot directly alter their pulmonary volume. II. Any change in thoracic volume is directly reflected in pulmonary volume. III. Thoracic volume change creates pressure gradients necessary for movement of air. IV. Lungs are made of solid muscle that contracts independently of thoracic cavity.
Statements I, II, and III are correct: Because we cannot directly alter pulmonary volume, the air-tight thoracic setup ensures thoracic volume changes alter pulmonary volume to generate pressure gradients. Statement IV is incorrect because lungs themselves lack muscle tissue to alter their own volume independently.
