In Class 11 Final Exams there will be Case studies and Passage Based Questions will be asked, So practice these types of questions. Study Rate is always there to help you. Free PDF Download of CBSE Class 11 Biology Chapter 17 Case Study and Passage Based Questions with Answers were Prepared Based on Latest Exam Pattern. Students can solve NCERT Class 11 Biology Breathing and Exchange of Gases to know their preparation level.

In CBSE Class 11 Biology Paper, There will be a few questions based on case studies and passage-based as well. In that, a paragraph will be given, and then the MCQ questions based on it will be asked.

Breathing and Exchange of Gases Case Study Questions With Answers

Here, we have provided case-based/passage-based questions for Class 11 Biology Chapter 17 Breathing and Exchange of Gases

Case Study/Passage-Based Questions

Case Study 1:

We have a pair of external nostrils opening out above the upper lips. It leads to a nasal chamber through the nasal passage. The nasal chamber opens into the pharynx, a portion of which is the common passage for food and air. The pharynx opens through the larynx region into the trachea. Larynx is a cartilaginous box which helps in sound production and hence called the sound box. During swallowing glottis can be covered by a thin elastic cartilaginous flap called epiglottis to prevent the entry of food into the larynx. Trachea is a straight tube extending up to the mid-thoracic cavity, which divides at the level of 5th thoracic vertebra into a right and left primary bronchi. Each bronchi undergoes repeated divisions to form the secondary and tertiary bronchi and bronchioles ending up in very thin terminal bronchioles. The tracheae, primary, secondary and tertiary bronchi, and initial bronchioles are supported by incomplete cartilaginous rings. Each terminal bronchiole gives rise to a number of very thin, irregular-walled and vascularised bag-like structures called alveoli. The branching network of bronchi, bronchioles and alveoli comprise the lungs. We have two lungs which are covered by a double layered pleura, with pleural fluid between them. It reduces friction on the lung-surface. The outer pleural membrane is in close contact with the thoracic lining whereas the inner pleural membrane is in contact with the lung surface. The part starting with the external nostrils up to the terminal bronchioles constitute the conducting part whereas the alveoli and their ducts form the respiratory or exchange part of the respiratory system. 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.

The lungs are situated in the thoracic chamber which is anatomically an air-tight chamber. 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. 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.

1.) ___________________ is undergoes repeated divisions to form bronchi and bronchioles

• a) Alveoli
• b) Bronchi
• c) Pleura
• d) Trachea

Ans: b) Bronchi

2.) Bronchiole gives rise to very thin, irregular-walled and vascularised bag-like structures known as

• a) Bronchi
• b) Pleura
• c) Larynx
• d) Alveoli

Ans: d) Alveoli

3.) What is pleura? Give its function.

Ans: Pleura – Both lungs are covered by a double layered pleura, with pleural fluid between them. It reduces friction on the lung-surface.

4.) Give reason – Why Larynx is known as sound box?

Ans: Larynx is a cartilaginous box that helps in sound production and is hence called the sound box.

The epiglottis is a thin elastic cartilaginous flap that covers the glottis.

5.) What is epiglottis? Give its function.

Ans: Function – prevent the entry of food into the larynx.

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